International Journal of Bio-Inorganic Hybrid Nanomaterials

International Journal of Bio-Inorganic Hybrid Nanomaterials

ABSTRACT

Keyword:

(*) Corresponding Author - e-mail: [email protected]

Nowadays, the technologies that are applicable to de-tect protein, DNA (Deoxyribonucleic acid), antigen-antibody and etc are time consuming, complex and expensive. For example, detecting DNA sequence with modern techniques needs several processing step. Bio-

-

Microarrays of different cells utilize to detect different type of solute biomolecule. After that, expensive mi-croarray laser beams are used to read cells [1]. In the past few years, researchers have introduces new elec-trical signal to eliminate these complex procedures.

Electrical detection methods exhibit highly sensitive detection of chemical and biological species because the surface analyte or analyte-analyte bindings occur very close to the channel. ISFET (Ion-Sensitive Field Effect Transistor) has received lots of attention due to their cheap price, small size, fast answer and the pos-sibilities for mass production [2, 3]. ISFET needs no optical reading and abeles to sense biomolecules with-

be used outdoors to control the spread of diseases and environmental pollution. Compatibility of ISFET with Modern microelectronics makes it possible to use am-

Review on Graphene FET and its Application in Biosensing

Mohammad Bashirpour

Ph.D., Department of Electrical and Computer Engineering, College of Engineering, University of Tehran, Tehran, Iran

1. INTRODUCTION

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 5-13 ISSN Print: 2251-8533 ISSN Online: 2322-4142

6

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 5-13 Bashirpour B

plifying and analyzing circuits with ISFET die on the

-

--

was intentionally removed exposing gate oxide. Dif-ferent experiments by Bergveld illustrated that con-centration of sodium chloride (NaCl) in solution re-sults in variation of current between drain and source.

-

2) used as the ion-sensing membrane to be sensitive to concentration of sodium (Na+) as well as hydrogen (H+) ions in the analyte so-lution [6].

Silicon transistor, because of their simplicity and well known fabrication process primarily used as IS-FET until recently that new low-dimensional struc-tures such as graphene nanoribbon, Si nanowires [7] and carbon nanotubes [8], have been applied. This is because of their size, large surface to volume ratio,

alternative for silicone ISFET is graphene based IS-FET that has really unique characteristics [9]. Since, graphene sheet electrical characteristics are sensitive

-tors (GFETs) have been reported in many research as biosensor for different analyte such as H+ ions, small molecules, proteins, DNA, viruses and cells [9]. Detection process takes place in ambient conditions where the analyte is in its reference condition. The analyte changes some properties in recognition layer

that is detectable with transducer. Graphene ISFET

performance of such a device was studied by Ang et

Graphene is a single layer of carbon atoms with hex-agonal lattice. Electrons in graphene act like relativ-istic particles without mass, which contribute to very unique thermal and electrical properties. Its proper-ties like high mobility, high saturation velocity for electrons and holes, good mechanical strength, high thermal conductance and ballistic transport made gra-phene attractive research area since its discovery in

-ibility, graphene based biosensors received lots of at-tentions from researchers hoping to create devices that are smaller in size, cheaper in price and more reliable than other systems using current technology. Mech-anism of this kind of sensors is that graphene chan-nel conductance changes with different biological or chemical species adsorption on surface of channel. Change in conductance results change in I-V char-acteristics. Biomolecules on the surface of the gra-phene act as electron donors or acceptors. The long

micrometers) implies that electrons can travel large distances through a device without being restricted. These properties can be very useful in biosensors to make very sensitive devices. Although graphene IS-FET possess high performances, there is lots of work needs to be done to conquest practical issues such as nanostructures uniformity and stability in fabrication

Figure 1: Schematic diagram of a graphene based ISFET. Positive (or negative depending on the applied

liquid-gate voltage) ions near the surface of the graphene make up the Debye layer [13].

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Bashirpour B Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 5-13

performance and fabrication process has been ex-plained. After that, interface between electrolyte/gra-phene is investigated in detail. At the end, graphene ISFET application in wide range of biosensors like DNA, cell and protein sensors has been reviewed.

2. GRAPHENE FET PERFORMANCE AND CHARACTRIZATION

Graphene ISFET is like silicon ones with little differ-ence that has huge effect on characteristics of transis-tor. The difference is graphene channel that makes device faster and more sensitive than typical silicon

-tion of the channel conductance is controlled by gate voltage from a reference electrode placed on top of the channel, across an electrolyte and electrolyte acts as the dielectric [16]. The gate voltage compels ions at the graphene/electrolyte interface, which in turn derive charge carriers by capacitive charging of the ideally polarizable interface. In particular, it has been shown that, because of the ambipolar nature of graphene, ad-

-) and hydronium (H3+) ions

are able to regulate the channel conductance by induc-ing holes and electrons, respectively. Figure 2 shows a typical conductivity vs. electrochemical gate potential plot obtained in an ionic liquid. The reaction between solution with different pH values and the surface of

It is obvious that device conductivity reaches a mini-mum value at charge neutral point [16].

Higher conductance graphene FET is because of

higher charge carrier mobility (material parameter) and the higher interfacial capacitance (depend on the device design).

3. GRAPHENE FET FABRICATION

Typically, the procedure of transistors fabrication is complicated, including preparation of substrate grown graphene, fabrication of electrode through photoli-thography and lift-off processes and deposition of source, drain and gate electrode. The most important part of graphene FET fabrication among several steps, is graphene sheet. Quality of 2-dimensional layer has huge effect on sensitivity and performance of biosen-sor. Fabrication of high-quality graphene in large vol-umes is vital for high performance and commercial devices. There are several major processes to achieve high quality graphene layer such as chemical vapor deposition (CVD) [17], mechanical exfoliation [18], thermal decomposition [19] and unzipping carbon

At its initial discovery, graphene was made with simple scotch tape. In this mechanical exfoliation

and then the tape was stuck together many times,

Since bulk graphite is simply many layers of the hex-agonal graphene lattice, when it is spread out over a large area, some spots will be one atom thick and ex-hibit the properties of graphene. This method produc-es best quality graphene layer. The primary disadvan-tage of this method is weak control on layer and small area (<1mm2) production that makes it inappropriate method for mass production [18].

Thermal decomposition of silicon carbide (SiC), al-though more costly than exfoliation methods, but can make large area graphene layer. As described in recent reviews, one approach is epitaxial growth of graphene layers on the basal faces of single-crystal silicon car-

The resulting graphene layers, which grow as silicon evaporates from the crystal, tend to show various de-fects such as substrate-induced corrugations [19].

For mass production, full sheet of graphene is nec-essary. It is achievable by CVD method. This process

Figure 2: Comparison of the transconductance of graphene

and Si ISFET [16].

8


catalyzes a reaction between substrate and gases un-der certain conditions [16, 17]. First of all, copper foil loads to containing chamber that is pumped down to

In the next step, methane gas enters vacuum cham-ber at higher pressure (6 mTorr). With help of hy-drogen gas as a catalyzer, decomposed carbon from methane deposits on copper foil. This reaction be-gins in isolated areas on the surface of the copper,

not perfect at these points. Carbon starts to assemble itself hexagonally from these sites until two domains

copper foil can no longer occur as soon as the lattice of carbon covers a section of copper. The result is a one-atom thick layer of carbon, which has auto-matically structured itself into the hexagonal lattice of graphene [22]. So far, we introduced three differ-ent method of graphene fabrication. In table.1 main methods are summarized.

Consequently, the graphene has to be removed from

the copper and transferred to an insulating substrate.

graphene/copper stack to provide mechanical stabil-ity to the graphene layer. This stack is placed on the surface of an iron (III) chloride solution, which etches the copper under the graphene. After diluting, the gra-

Figure 3: Graphene oxide reduction process steps [21].

Method Description

Mechanical exfoliation (repeated peeling) of3D graphite crystals with Scotch tape.

EpitaxialGrowth Berger et al. [19]

Thermal decomposition of SiC in high vacuumand at high temperature

CVDUsing the atomic structure of a metal substrate

to seed the growth of the graphene

ChemicalMethod Choucair et al. [21]

A direct chemical synthesis of grapheneNano sheets in a bottom-up approach based on

ethanol and sodium reagents.UnzippingNanotube Koshynkin et al. [22]

Unzipping multiwall carbon nanotubes byplasma etching

Table 1: Main methods of producing graphene.

Figure 4: Graphene transfer process. (a) Graphene is

grown via CVD on copper foil. (b) PMMA is spun on top of

graphene. (c) Copper foil is removed with an etchant bath.

(d) Graphene with PMMA is transferred to Si/SiO2 substrate.

(e) PMMA is removed [15].

9


-rication process of GFET, multiple steps have to be

2 substrate then patterns for alignment marks. Af-ter that, chrome alignment marks have to be deposited via e-beam metal evaporation and remaining metal and photoresist has to strip. In next step, graphene has

2 -ing, photoresist has to spin on top of graphene and pat-

2 plasma etching and remaining photoresist has to be stripped to make channel of device. For creating ohmic metal electrodes, same lithography like channel patterning

After devise fabrication, a passivation layer has to spin coated and patterned on GFET. Channel is the only part of transistor that can be in contact with an-alyte and metal electrodes has to be insulated. The device have to wire-bonded so can be characterized. The bonding wires have to cover with silicone glue to insulate them from the analyte [23].

4.GRAPHENE FET BIO APPLICATION

a) DNA Sensor-

vestigation on graphene and DNA interaction. They -

lent device for biocellular and bimolecular scale. They have investigated single bacterium and DNA interac-tion with graphene sheet [23]. First, they had immobi-lized single strand DNA on graphene sheet. After that,

the end hybridized with target DNA. They saw this

method feasible for DNA sequencing detection.

CVD graphene from Ni substrate to glass to fabricate graphene transistor. Their device detects hybridization of target DNAs to the probe DNAs pre-immobilized

-ed the Au nanoparticles on graphene sheet and could

[22]. According to Dong et al. research, device con-ductance shows amipolar behavior subjecting to ap-plied gate voltage. They have showed that Vg-min is sensitive to probe DNAs immobilization and hybrid-ization. As shown in Figure 6, increasing in analyte concentration shifts minimum gate voltage (Vg-min) to the left and decreases GFET current for the same ap-plied gate voltage.

Chen et al. [23] fabricated low noise GFET on large area graphene. Their GFET sensitivity achieves the concentration as low as to 1 pM. They investigated graphene surface cleanness effect on interaction be-

Figure 5: Graphene FET fabrication process. (a) PMMA

Spin Coating on Si/SiO2. (b) Photoresist patterning. (c)

Metal deposition and photoresist removing. (d) Graphene

growth on Si/SiO2 substrate and PMMA spin coating on it.

(e)Graphene channel patterning. (f) Photoresist removing.

(g) PMMA spins coating. (h) Electrode patterning. (i) Metal

deposition and photoresist removing [23].

Figure 6: Transfer characteristics for the graphene tran-

sistors before adding DNA, after immobilization with probe

DNA, and after reaction with complementary [24].


tween DNA and graphene. They have used gold trans--

Most of methods are using single graphene ISFET

al. [26] have introduced new multiplexed DNA array Graphene ISFET. They have created 8-FET DNA sen-sor array based on CVD-graphene with maximum sen-

than other state-of-the-art CVD graphene FET [27]. It also better than commercial optical DNA sensing that has sensitivity in order of 1 pM [28]. They have used graphene in two different functions as a site spe-

(Figure 7).

was to sense pH of a solution. First pH sensor was in-

troduced with multilayer graphene sheet as a channel that was grown on SiC substrate [11]. According to that research sensitivity was 99 mV/pH and difference in graphene layer number had almost no effect on sen-sitivity. Ag/AgCl was used as gate electrode.

Donkerl et al. have used epitaxial graphene on 6H-SiC substrate to fabricate ion solute gate FET array for pH sensing. They have investigated charge carrier mobility and concentration as a function of electrolyte gate potential. They have used UV-

transistor [29].Wang et al. have fabricated oxide on graphene bio-

FET for pH sensing. They passivated graphene chan-

2 -ing/immobilizing and protection layer. In this research

2 -nopropyl) trimethoxysilane) as a pathway for DNA and protein immobilization. They have investigated

-

as a glucose sensor. Fabricated sensors sensitivity was

for reference examination or screen test for diabetes diagnostic.

The sensor uses detection of H2 2 as a function of glucose. They saw that, as the H2 2 concentration in-

where the channel conductance is minimized was shifted towards lower value of Vg [31].

In Table 2, voltage sensitivity of different GFET pH sensors report in literature is compared. Main reason for huge difference in sensitivity is not been well un-

and unintentional chemical functionalizations have an important role in GFET quality and so sensitivity.

Figure 7: Graphene FET array and experimental set up [26].

Ang et al. [11] Fu et al. [32] Cheng et al. [33]

Sensitivity(mV/pH)

99 27 6 18

Graphene source Epitaxial Exfoliation CVD Exfoliation

Table 2: Comparison of graphene PH Sensor sensitivity according to different graphene sheet fabrica-tion process.

11


c) Protein SensorGFETs, because of their large area and high mobility are really excellent device for protein, anti body and antigen detection. In recent years, there has been lots of research for improving sensitivity of GFET biosen-

investigated vertically aligned graphene FET grown on -

sitivity was 12 pM and showed really good selectivity for Immunoglobulin G (IgG) protein. They showed that vertically-oriented graphene (VG) facilitates the deposition of gold nanoparticle-antibody conjugates on transistor. In other work they showed that attaching

gold nanoparticle-antibody will decrease transistor current. They have used thermally reduced graphene FET to investigate immune system of human body. Binding of antibody and antigen can be detected with I-V characteristics of vertically aligned GFET (Fig-

channel for GFET for detection of heat shock protein

In other work, Kim et al. reported self aligned re-duced graphene oxide FET for label free detection of

Figure 8: Dynamic response of the VG sensor exposed to different concentrations of IgG (a) with and (b) without probe

-

sitivity in response to complementary IgG (2 ng/mL), mismatched IgM (0.2 mg/mL), and mismatched HRP (0.2 mg/mL).

Figure 9: Schematic of R-GO FET fabrication and detection

of PSA-ACT complex. (a) Self-assembly of GO nanosheet.

(b) Formation of Ti/Au source and drain electrodes. (c)

Functionalization of R-GO channel by linker molecules. (d)

Illustration of R-GO FET immunosensor with Pt reference

electrode in the analyte solution [36].

Figure 10: Current-gate voltage characteristic (I-VG) of gra-

phene FET after each step required for functionalization with

fusion protein GST-BT5: as prepared (black), after diazoni-

um treatment (red dashed), after Ni-NTA attachment (green

dotted), and after incubation in protein (GSTBT5) solution

(blue dot-dash) [36].

12


prostate cancer [36]. They showed that analyte con-centration has linear effect on gate minimum voltage

concentration makes Vg-min shift to left and for pH= 6.2,increasing in analyte concentration results in Vg-min

shift to right. In addition to gate voltage, conductivity

analyte concentration increase (Figure 9).-

hictidine-tagged protein to graphene FET and used -

fect in device. They have applied three different light

-

G shift is observed only for violet illumination, with negligible change for green or red light. They conclude that cur-

can be concluded that GFETs device may be superior to electrode device in certain aspect.

5. CONCLUSIONS

In this review, fabrication, characterization and appli-cation of GFET has been discussed in biosensor de-

detection for new methods of cancer detection. Due to excellent electrical and mechanical properties like high carrier mobility and capacity graphene has shown really amazing exclusivity in bio area. Along with its great results, GFET has shown numerous challenges for mass production. First one is large area production of high quality graphene. Nowadays most promising method to achieve high surface area graphene is CVD method. Another challenge is graphene tendency to absorb hydrocarbons that contaminates the surface of

-cation steps that introduce contamination in graphene

of contamination in this step. With these advantages consideration, it is obvious that graphene will brings

amazing future for electronic and biosensor future ap-plication.

REFERENCES

J. Biol. Tech., 14

Biosens Bioelectron, 16

Sensors, 97111.

Sensors, 9 Seen Actuators B Chem., 88

1.6. Abe H., Esashi M., Matsuo T., IEEE Trans Elec.

Devices, 26 (1979), 1939.7. Clement N., Nishiguchi K., Dufreche J.F., Guerin

D., Fujiwara A., Vuillaume D., Appl. Phys. Lett., 98

-gan, G. J., Chen, Y., & Star, A., Sci Rep., 4

Small, 10

Saha S.K., Waghmare U.V., Sood A.K., Nat Nano-technol., 3

J. American Chem. Soci., 130

K., Nano Lett., 9

M., Hashim A., Nanoscale Res. Lett., 8

Science, 306666.

K.S., & Geim A.K., Rev. Modern Phys., 81

Proceedings of the IEEE, 101

J. Phys. Chem. Lett., 1

13


Chem. Rev., 110

C., de Heer W.A., Science, 312

Nat, 458Nat Nanotechnol, 4

217.

Science, 324-

Nano Res., 7Ad-

vance Mat, 22

Biosens Bioelectron, 41

Yoon H., Ham D., Nat Commun., 5Advance Mat., 25

168.-

Nat Biotech-

nol., 24

Birner S., Sharp I.D., Garrido J.A., Advanc Func-tion Mat., 20

- Nano Res., 7

31. Kwak Y.H., Choi D.S., Kim Y.N., Kim H., Yoon D.H., Ahn S.S., Seo S., Biosens Bioelectron, 37

Weiss M., Calame M., Scheonenberger C., NanoLett., 11

NanoLett., 10

Sci. Rep., 3Nano Res., 4

Biosens Bioelectron, 41621.

J.H., Discher B.M., Johnson A.C., Appl. Phys. Lett., 100


ABSTRACT

3

Keyword:


Nanotechnology has had an immense impact on nearly

unique physiochemical and optical properties due to

the top of the rapidly increasing list of materials being investigated in the nanostructured [1]. In recent years,

that there is an expanding research in the synthesis of

-ment of novel technologies [1, 2] Silver nanoparticles

areas, such as, catalysts [2], because of their morphol-ogy play important role in controlling the physical, chemical, optical, and electronic properties of these nanoscopic materials [3]. In this work, copper anode slime of Kerman Sarcheshmeh cooper complex that

Synthesis Silver Nanoparticles by Recovery Silver from Anode Slime of Kerman Sarcheshmeh Cooper Complex

Hojat Zahedi1, Afsaneh Mollahosseini2*, Ebrahim Noroozian3

1 M.Sc., Department of Chemistry, Iran University of Science and Technology, Tehran, Iran2 Assistant Professor, Department of Chemistry, Iran University of Science and Technology, Tehran, Iran

3 Associate Professor, Department of Science, Shahid Bahonar University of Kerman, Kerman, Iran

1. INTRODUCTION


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Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 15-19 Mollahosseini A at al

is in south east of Iran was under analyzing. Anode Slime is characterized by higher amount of Ag, Se,

amount of Au. There is interest in studying methods for recovery of these metals from anode slime. Impu-rities must also be removed from anode slime before

chemical route, since discovered, has been studied for yielding kinds of nanomaterials, especially noble metal nanoparticles, such as silver, gold and platinum [6, 7]. Among these researches, chemical method un-der sonication has been applied widely due to the rela-tively high reductive ability of it [8, 9].

2. EXPERIMENTAL

sodium hydroxide and polyvinyl pyrrolidone were obtained from Merck.

All glassware were washed with deionized water

added and AgCl was obtained from the leach solution. Silver chloride was collected and dissolved in ammo-

drop by drop for obtain pH 12. In this time solution

from yellow to dark brown. This solution immediately was transferred to ultrasonic bath and sonicated for

separated from the solution by vigorous centrifugation -

ing agent and then re-dispersed in distilled water. In

-

-

scanning electron microscopy (SEM) SBC12.

3. RESULTS AND DISCUSSION

In order to characterize silver percent in anode slime,

2

To separate silver from anode slime, acid leaching was used. The anode slime was leached with nitric

well as Ag. In order to Ag separation from other com-ponent, HCl was added and silver was precipitated as

2 that both of them were white solid.

2 was removed by washing hot water.

(1)

(2)

(3)

Composition Composition Composition

Al2 3 As2 3 Fe2 3

2 2 2.6 2 13.7

Ag2 3.8 Sb2 3 2

Au 1 Cl7.23.6 37.32 2 22.7

Table 1: XRF analysis of anode slime.

3 3 3 2

2 3 3 2

3 3 2 2

17

Mollahosseini A at al Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 15-19

(6)

(7)

(8)

(9)

(11)

According to previous study alkaline solution for syn-

- injected to solution makes accelerate the reaction and help dextrose and pvp to converted

Ag+

-

Scanning electron microscopy (SEM) image in -

in nanosize and their spherical morphology that was prepared by this method.

-

of particles and volume of particles that was occupied. -

ical and the formula of spherical volume that is V= 3, so as particles in a space or volume be more

3 3 2 2

2

2

3 3 2AgCl 2NH [Ag(NH ) ]Cl

3 2 3

Figure 1: UV-Vis absorption spectra for SNPs powder without sonication and after sonication with 2 hours.

Table 2: Band Gap Energy.

Joules

C = Speed of light 8 meter/sec-9 meter

-19 Joules-19 3.21 eV Figure 2: SEM image of SNPs after 2 hours sonicating.

18

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 15-19 Mollahosseini A at al

the plot of these particles is more too. For this reason

is more.Energy dispersive spectroscopy (EDS) was used to

analyze the chemical composition of a material. EDS

peak of silver in their plot in 3, 23 and 26 KeV. The

Figure 3: DLS analysis for SNPs size distribution by number.

Figure 4: DLS analysis for SNPs size distribution by volume.

Figure 5: EDS spectra for SNPs under 2 hours sonicated.

19

Mollahosseini A at al Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 15-19

-

the standard data.

4. CONCLUSIONS

In summary in this work leaching of anode slime showed that almost all of silver could be separated

using of dextrose and pvp in the role of reduction and

the concentration of silver cation in proportion to the concentration of pvp was kept constant during all the

the nucleation sites and acting as surfactant. This -

fabricating composite because of simple process and condition.

ACKNOWLEDGEMENT

-search Council of Kerman Sarcheshmeh Copper Complex and Iran University of Science and Technol-

ogy (IUST).REFERENCES

3rd Conference on Nanostructures

2. Khaleghi A., Ghader S., Afzali D., Int. J. Mining Sci. Technol., 24

3. Das S., Motiarkhan M., Guha A., Das A., Mandal A., Bioresource Technol., 124

J. Nano-technology, 6

G., Jie W., Ultrason. Sonochem., 21J. Chin. Inst. Chem. Eng., 39

Colloids surf. B, 102

8. Norouzi M., Soleimani M., National Conference on Nanotechnology and Green Chemistry, Tehran,

Mater. Chem. Phys., 94

Colloids Surf. A: Physicochem. Eng. Aspects, 390

Ma-ter. Chem. Phys., 94

Catal. Sci. Technol., 4

Table 3: Output results of EDS analysis of SNPs under 2 hours sonicate.

Elem. Intensity Formula

16 S K 2.12 S22 Ti K 2

26 Fe K 1.77 Fe2 3

29 Cu K 3.31K 7.83 2

K 97.39 Ag

3.77


ABSTRACT

Keyword:

Biodegradable polymeric nanoparticles have attracted interests in a broad range of applications in nanotech-nological devices. They could be utilized as peptide and protein delivery vehicles and desirably preserve

enzymes into polymeric matrix.In drug delivery systems having a monodisperse col-

loid of nanoparticles or achieving minimum polydis-

the nanoparticle distribution and thus bioavailability. The sizes of nanoparticles determine their penetration into cell membranes, binding and stabilization of pro-teins, and lysosomal escape after endocytosis. They are also better suited for intravenous (i.v.) delivery.

Chitosan, a linear aminopolysaccharid composed

Morphology Improvement of Chitosan Nanoparticles as Protein Delivery Vehicles

Nasim Kiaie1, Rouhollah Mehdinavaz Aghdam2*, Hossein Ahmadi Tafti3**,Shahriyar Hojati Emami4, Jalal Izadi Mobarakeh5

1 M.Sc., Department of Tissue Engineering, AmirKabir University of Technology, Tehran, 15875, Iran2 Ph.D., Tehran Heart Hospital Research Center & Nanotechnology Department,

Space Transportation Research Institute, Tehran, Iran3 Professor, Tehran Heart Hospital Research Center, Tehran, Iran

4 Ph.D., Department of Tissue Engineering, AmirKabir University of Technology, Tehran, 15875, Iran5 Ph.D., Department of Physiology and Pharmacology, Pasteur Institute of Iran, Tehran, 13164, Iran

1. INTRODUCTION


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Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 21-24 Mehdinavaz Aghdam R et al

and N-acetyl-d-glucosamine units, gained increased attention for drug delivery systems in view of its biocompatibility, non toxicity, low immunogenicity, biodegradability and cationic properties [1-3].

Several methods have been used for chitosan parti-cle preparation including emulsion, ,solvent evapora-tion, iontotropicgellation, spray drying, reverse micel-

the mentioned methods, ionic gellation method has -

tein delivery because of non toxicity, being organic solvent free controllablity, being convenient, mild and in a sense protein friendly [6]. In this method, inter-action of amino groups of chitosan with negatively

-sponsible for ionic crosslinking [7].

Nanoparticle formation seems to be very sensitive to processing conditions such as ambient and chitosan solution temperature [6, 8], stirring rate [6, 8], ultra-sonic exposure [8], crosslinking time [9], molecular weight, degree of deacetylation and concentration of

-centration [6, 9, 16 and 17], pH of chitosan solution

[16]. This paper will focus on varying processing con-ditions in order to achieve the best morphology and size of nanoparticles made from chitosan as peptide delivery vehicles.

2. MATERIALS AND METHOD

-

and BSA were purchased from Sigma-Aldrich chemi-

We determined the hydrodynamic diameter of

Instruments, UK).The shape and morphology of the nanoparticles

-kled onto a glass slide and after complete drying was mounted on an SEM stub and sputter-coated with gold in an argon atmosphere. The coated samples were ex-

were prepared in acetic acid aqueous solution at room temperature and stirred for 2 h at high speed to ob-

solutions were ultralsonicated for 1 min and formed nanoparticles were concentrated by centrifugation at

and were re-suspended in ultrapure water.


As it is mentioned before, size and polydispersity of nanoparticles are important for drug delivery sys-

as proteins leads to higher amounts of size. Control of process parameters such as chitosan concentration,

-

--

ble 1. It is evidence from Table 1 that with increasing pH more compact and smaller nanoparticles formed. Also, polydispersity values were reduced with in-creasing pH amounts.

Noteworthy, achieving narrow distribution for chi--

posed of a wide distribution of low, medium and high

Sample pH pdIHydrodynamic diameter

(nm)ABC 6

Ch concentration 0.16% (w/v), BSA concentration 0.88% (w/v, Ch:TPP 5, solution temperature 60°C. R2= 0. 94for size and R2= 0.99 for polydispersity.

Table 1: Samples and experiments conditions.

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Mehdinavaz Aghdam R et al Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 21-24

molecular weights. This observation stems from ionic gellation concept. In this process, electro-positive amino hydrogen of

each other electrostatically [11] admittedly, increasing pH may decrease protonation of molecules. In con-clusion, less NH3

+ Binding sites on chitosan molecules exist.

Also, Mi et al. [12] illustrated that in the aqueous

3 , H2 3 3 varying accord-ing to pH alterations in solution. pH increase leads to

smaller nanoparticles are formed.In higher solution temperatures viscosity of chitosan increase and consequently molecules approach each other, attractive forces get on the top of repulsive ones between NH3

+ sites causing small and compact nanoparticles as it is presented in Figure 1.

In this study, morphology of nanoparticles as it is depicted in Figure 2 is favorably smooth and spherical in shape which is in accordance with Britto’s results [13].

In this picture spherical nanoparticles are ranging

Figure 1: Effect of chitosan solution temperature on hydrodynamic diameter. Ch concentration 0.16% (w/v), BSA concentration

0.88% (w/v), Ch:TPP 5. D and E at pH= 4.5, F and G at pH= 6.

D: nm E: nm

G: nmF:

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 21-24 Mehdinavaz Aghdam R et al

of clusters of several nanoparticles comes into be--

tails of these features. It is evident that The size of the nanoparticles based on the FE-SEM micrographs

the second is hydrodynamic diameter which is larger due to the ability of chitosan to swell in contact with

4. CONCLUSIONS

According to our study it shows that varying the

(chitosan solution temperature and pH increasement) might have a linear relationship with size and nar-row down polydispersity. Seemingly, we are able to present that nanoparticles morphologies were spheri-

favorable size in the case of protein loaded chitosan nanoparticles.

REFERENCES

1. Kumari A., Yadav S. K., Yadav S.C., ColloidsSurf., B., 75

2. Amidi M., Mastrobattista E., Jiskoot W., Hennink W.E., Adv. Drug Delivery Rev., 62

Int. J. Phy-torem., 274

T. M., J Control Release, 100

C., Adv. Drug Delivery Rev., 62Colloids Surf., B.,

90Pharm.

Res., 6Carbohydr.

Polym., 71

J.S., Int. J. Pharm., 249

Alonso M. J., Pharm. Res., 1411. Sun Y., Wan A., J. Appl. Polym. Sci., 105

J.Polym. Sci. Part B: Polym. Phys., 37

-Food Hydrocolloid,

27

Int. J. Pharm., 430

Figure 2: Above: SEM picture of nanoparticles at pH=

4.5 and solution temperature of 25°C. Below: FE-SEM of

nanoparticles at pH= 6 and solution temperature of 60°C.

(Chitosan concentration 0.16% (w/v), BSA concentration

0.88% (w/v), Chitosan: TPP= 5).


ABSTRACT

+

Taxus baccata L.Taxus baccata L.

Escherichia coli Acinetobacter baumanniiKlebsiella pneumoniae Staphylococcus aureus

Aspergillus oryzaeTaxus baccata

Keyword: Taxus baccata


Fundamental and applied physico-chemical research in

boom in the last few years. Nano materials attract at-tention due to their unique physico-chemical proper-ties that are rooted in their diameter, eventually in their large surface area. These unique properties cannot be additionally found for the chemically identical material

-

be continuously more and more frequently found not

and chemical technologies but also as a part of com-mon life due to their usage in commercially available products [1, 2]. Silver ions and silver-based compounds are highly toxic to microorganisms. Thus, silver ions have been used in many kinds of formulations [3], and

Synergistic Effects of Taxus baccata Extract Mixtures with Silver Nanoparticles against Bacteria and Fungal

Mehrorang Ghaedi1 2, Leila Delshad3*

1 Professor, Department of Chemistry, Yasouj University, Yasouj , Iran2 Assistant Professor, Department of Biology, Yasouj University, Yasouj , Iran

3 M.Sc. Department of Chemistry, Yasuj University, Yasouj, Iran

1. INTRODUCTION


26

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 25-30 Delshad L et al

recently it was shown that hybrids of silver nanoparti-cles with amphiphilic hyperbranched macromolecules

-

6]. These low concentrations are not additionally toxic

be, due to its high antibacterial activity, low toxicity against higher organisms and unproved bacterial re-sistance, considered one of the greatest antibacterial agents for the treatment of burns [8] or for the preven-tion of bacterial colonization on catheters, prosthetics

Antibiotics are one of our most important weapons -

their introduction. However, over the past few de-

commonly used antibiotics have become less and less effective against certain illnesses not only because many of them produce toxic reactions but also due to emergence of drug resistant bacteria. It is essential to investigate newer drugs with lesser resistance. Sys-tematic studies among various pharmacological com-pounds have revealed that any drug may have the pos-sibility of possessing diverse functions and thus may have useful activity in completely different spheres of medicine. Drugs derived from natural sources play

human diseases. In many developing countries, tra-ditional medicine is one of the primary health care systems [16, 17]. Herbs are widely exploited in the traditional medicine and their curative potentials are well documented [18]. Taxus baccata or the Europe-an yew is distributed throughout the temperate zones of the northern hemisphere. It is a small to medium-sized evergreen tree that historically has been used for weapon-making and medicine, and is poisonous except for the fruit [19]. The genus Taxus belongs to

Taxaceae. As the species are highly similar, they are often easier to separate geographically than morpho-

The genus Taxus has generated considerable interest due to its content of diterpene alkaloids, particularly taxol (known also as the generic drug paclitaxel and

by the registered trade name Taxol® BMS [Bristol-Myers Squibb]). The anticancer properties of taxol were discovered in T. brevifolia extracts in 1971 [21]. This plant is used traditionally for the treatment of

leaves of this plant are used to make herbal tea for -

tures on T. wallichiana have reported immunomodula-tory, anti-bacterial, anti-fungal, analgesic, anti-pyretic and anti-convulsant activities [22, 23].

2. MATERIALS AND METHODS

2.1. Plant materialFresh leaves of the forests of northern Iran were col-lected. Then plant was washed thoroughly with tap water followed with sterilized distilled water for the

shade dried in the dark at room temperature for few -

2.2. Preparation of plant extracts

--

distilled water) respectively and stored at room tem-

-due was re-extracted with equal volume of solvents.

-pernatants were evaporated to dryness under vacuum

South Korea) evaporator. The obtained extracts were kept in sterile sample tubes and stored in a refrigera-

extract was subjected to subsequent analysis. Silver

2.3. Antibacterial activity (in vitro)

27

Delshad L et al Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 25-30

activities by disk diffusion method at Muller Hinton agar medium (Merck, Germany) against three Gram-negative bacteria such as E. coli (ATCC33218), and Acinetobacter baumannii Klebsiellapneumoniae (ATCC1827) and also Gram-positive bacteria including S. aureus

6 colony-

of the plates and then swabbed and kept for adsorp-

diameter) were loaded with trial samples which had

-rial activities of compounds were evaluated based on diameter of zone of inhibition (mm) and tabulated in

-ronment. Gentamicin and for Gram-positive bacteria, Cephalexin were used as reference bactericidal drugs (positive controls).

The lowest concentration that prevents the growth of bacteria is considered as MIC. The MIC of the

-rium based on a broth dilution method (Table 2). In this method, various concentrations of compounds

--

ing a loop full of broth dilution MIC tests to Muller Hinton Agar medium on a plate and then incubated at

-terial growth on the surface of agar medium (Table 2).

2.6. Antifungal effects

two fungal strains such as A. oryzae. For activity mea-surement, the prepared discs (that had been soaked in

on a surface of petri plates covered by Sabouraud dex--

A. oryzae (Table -

photericin B was chosen.


3.1. Antibacterial bioassay (in vitro)The antimicrobial activity of Compounds (extract,

-

Gram positive

Compounds Staphylococcusaureus

Acinetobacterbaumannii

Klebsiellapneumoniae

Escherichia coli

8.639.729.3311.8311.73Extract16.1211.2313.72

13.3212.339.2216.8212.62Mixture

Table 1: Antibacterial activities of constructed disks soaked in 80, 40 and 20 mg/mL of compounds (extract, Ag-NPs, mixture of extract with AgNPs) in diameter zone (mm) on various bacterial strains.

28


against four pathogenic bacterial strains Gram posi-tive S. aureus -tive E. coli (ATCC33218), Acinetobacter baumannii

Klebsiella pneumoniae (ATCC1827). The results of the antibacterial activities are presented in Table 1 and Figure 1. The acquired results revealed

standard antibiotics (Gentamicin and Cephalexin) in our conditions the antibacterial activity of the Com-

-

-

E. coli,while extract had lowest effect against S. aureus. For

Figure 1: Zone of the inhibition of the growth of constructed disks (soaked in 80, 40 and 20 mg/mL) of compounds against

four bacteria.

Bacteriaextract Taxus baccataBio Silver nanoparticles

Extract and synthesized silver nanoparticles

MBCMICMBCMICMBCMIC

S. aureusE.coli

AcinetobacterbaumanniiKlebsiella

pneumoniae

Table 2: Antibacterial activity (MBC and MIC in mg/mL) Taxus baccata L. extract and silver nanoparticles and their combination microdilution method.

29

Delshad L et al Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 25-30

-tion showed which is equal to 13.22 mm against Kleb-siella pneumoniae and for the bacterial extract when mixed with silver nanoparticle inhibition zone diame-

that the synergistic combination of the antibacterial -

timicrobial effects. As it was noted above, the deter-mination of the bactericidal effect of the Compounds

the reference strains of Staphylococcus aureus, Esche-richia coli, Klebsiella pneumoniae and Acinetobacterbaumannii was achieved by means of the dilution method MIC (minimum inhibitory concentration) and MBC (minimum bactericidal concentration). MIC of Taxus baccata L.for inhibition of growth of Acinetobacter baumannii,

Esch-erichia coli. MIC and MBC mix Taxus baccata L. ex-

Staphylo-

coccus aureus. In the case of Acinetobacter baumannii

belonged to Taxus baccata L. activity of the medicinal

3.2. Antifungal bioassay (in vitro)In addition to antibacterial activities, compounds (ex-

subjected to antifungal activities against A. oryzae fungal strain and the zone diameters of inhibition (mm) have been summarized in Table 3. Also for a clear comparison, the zone of the inhibition of the

has excellent antifungal activity on used funguses with respect to extract and mixture extract with Ag-

-

antifungal activity.

4. CONCLUSIONS

-sent any risk for human beings, when used in medical applications and commercially available products, but only under the condition that the silver concentration

suppression of bacterial and yeast growth. Antimicro-bial properties of medicinal plants are being increas-ingly reported from different parts of the world. The world health organization estimates that plant extract or their active constituents are used as folk medicine

CompoundsAspergillus oryzae

Extract 6.23 8.129.87

Mixture 9.21

Table 3: Antifungal activities of constructed disks (soaked in 80, 40 and 20 mg/mL of compounds (extract, extract with AgNP, AgNP) based on diameter zone (mm) against fungal Aspergillus oryzae.

Figure 2: Zone of the inhibition of the growth of constructed

disks (soaked in 80 mg/mL) of compounds against fungal

Aspergillus oryzae.


-tion. In the present work, extracts obtained from Taxus baccata L. shows strong activity against most of the tested bacteria and fungal strains. The results were compared with standard antibiotic drugs. From the above results the activities of hydroalcohol extracts of Taxus baccata L.antifungal activity. The results showed that the Taxus baccata L. extract against bacteria and fungus inhibit-ing effect was tested. Applications of Ag nanoparticles

--

microbial systems.

REFERENCES

Toxicol. Lett., 176

Biotechnol. Adv., 27

3. Sondi I., Salopek-Sondi B., J. Colloid Interf. Sci.,275

Chem. Commun., 24

J. Phys. Chem. B, 110

Biomaterials, 30

J. Phys. Chem. C, 113

J.Med. Microbiol., 55

9. Gosheger G., Hardes J., Ahrens H., Streitburger A., Buerger H., Erren M., Gunsel A., Kemper

F.H., Winkelmann W., Von Eiff C., Biomaterials,25

Ann. In-tern. Med., 144

J.Hosp. Infect., 62

Bio-materials, 27

13. Kollef M.H., Afessa B., Anzueto A., Veremakis -

Jama-J. Am. Med. Assoc., 300

-J. Antimicrob. Chemoth., 61

-

Biomaterials, 25J. Ethnopharmacol., 38 (1993),

J. Altern. Complement. Med., 1

Curr. Sci., 86

Simbo-lismo, Mitosy tradiciones, Plantaciony cuidados,Barcelona: Ediciones Integral.

Bot Rev., 64 (1998), 291.

A., J Am. Chem. Soc., 93

Kaleem W.A., Khan I. et al., Phytother. Res., 26

Gilani S. et al., Med Chem. Res., 22 J. Ethnopharmacol., 74

-da T.B., Eur. J. Med. Chem., 45


ABSTRACT

Keyword:


2 particles are of interest due to their unique properties and several po-tential technological applications such as photocataly-

2

exists in three polymorphic phases: rutile (tetragonal 3 3)

3). Both anatase and rutile have tetragonal crystal structures but belong

to different space groups. Anatase has the space group

1/amd with four formula units in one unit cell and ru-

2 2 formu-

phases are less stable and undergo transition rutile in the solid state. Among the three above mentioned crys-

2, anatase owing to its higher pho-tocatalytic activity is commonly used for photocataly-

Synthesis of Nano-Sized Titania Particles by Hydrolysis of Titanium Tetrachloride

Majid Farahmandjou1*, Mahbobeh Ramazani2

1 Associate Professor, Department of Physics, Varamin-Pishva Branch, Islamis Azad University, Varamin, Iran2 M.Sc., Department of Physics, Varamin Pishva Branch, Islamis Azad University, Varamin, Iran

1. INTRODUCTION


32

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 31-34 Farahmandjou M & Ramazani M

sis [11]. This higher photocatalytic activity is related to its lattice structure. Each Ti atom is coordinated to six oxygen atoms in anatase tetragonal unit cell. The

its symmetry is lower than orthorhombic. The Ti-Ti -

tances are shorter than in rutile. In the rutile structures -

drons, while in the anatase structure each octahedron is in contact with eight neighbors. These differences in lattice structures cause different mass densities and electronic band structures between the two forms of

2. The low-density solid phases are less stable and undergo transition rutile in the solid state. The trans-formation is accelerated by heat treatment and occurs

transformation is dependent on several parameters such as initial particle size, initial phase, dopant con-centration, reaction atmosphere and annealing tem-

2 nanoparticles can be synthesized using vari-

hydrothermal method [18, 19], direct oxidation of TiClmethod, etc. [1, 21]. Wet chemical method has novel features which are of considerable interest due to its low cost, easy preparation and industrial viability. Anatase phase are commonly obtained by hydrolysis of titanium compounds, such as titanium tetrachloride (TiCl ) [22]. In this study, we report the synthesis of

2 nanoparticles system by wet chemical route. An-

2 are obtained by TiClprecursor. The morphology of the nanoparticles has

2. EXPERIMENTAL DETAIL

The titania nanoparticles were synthesized by drop wise addition of titanium tetrachloride: TiCl

at room temperature while stirring under a fume hood due to the large amount of Cl2 and HCl gases evolved in this reaction. The resulting yellow solution was al-lowed to rest and cool back to room temperature as the

gas evolution ceased. The suspensions obtained were -

2 particles were obtained. After

2 2 was added to the solution. The light yellow colored solution changed to red colored. The total volume of the solution was

vessel. The obtained powder samples were calcined

an ambient atmosphere. The morphology of the as-

2 nanoparticles were done.

crystalline phase and to estimate the crystalline size.

-sion scanning electron microscopy (SEM) with type

-


crystalline phases and to estimate the crystalline siz-

2

nanoparticles and indicates the structure of tetragonal

diffraction planes, respectively are in accordance with

2 anatase phase. It can be seen the peak posi-

2 nanoparticles has been estimated from full width at half maximum (FWHM) and Debye-Sherrer formula according to equation the following:

(1)

-length, B is the line broadening at half the maximum

-

DBcos

33

Farahmandjou M & Ramazani M Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 31-34

2 nanoparticles was 7 nm from this Debye-Sherrer equation.

The crystal structure of the nanoparticles before (red

analysis. It is realized that in the rutile phase the size

2

nm when the nanoparticles prepared with nitric acid (green line).

Scanning electron microscope (SEM) was used for

2.These Figures show that high homogeneity emerged in the samples surface by increasing annealing tem-perature. The results show that with increasing an-nealing temperature the morphology of the particles changes to the spherical shape and nanopowders are less agglomerated. Figure 2(a) shows the SEM images

2 nanoparticles with sphere-like shaped prepared by wet chemical method. Fig-

2

nanoparticles prepared in presence of nitric acid at

2 nanoparticles prepared in absence of nitric acid.

2 nanoparticles are not ag-glomerated. In this Figure, the spherical shaped parti-cles with clumped distributions are visible through the SEM analysis. The average crystallite size of annealed

-ticles synthesized in presence of nitric acid.

The transmission electron microscopic (TEM) anal-

the particles. Figure 3 shows the as-synthesized TEM image of titanium dioxide prepared by wet synthesis.

(a) (b)

(c)

Figure 1: XRD pattern of TiO2 nanoparticles (a) as-prepared

(red line) (b) annealed at 600°C without nitric acid (blue line)

(c) annealed at 600°C with nitric acid (green line).

Figure 2: SEM images of the TiO2 nanoparticles (a) as-prepared (b) annealed at 600°C in presence of nitric acid

(c) annealed at 600°C in absence of nitric acid.

Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 31-34 Farahmandjou M & Ramazani M

2 nanoparticles is about 7 nm in diameter.

4. CONCLUSIONS

2 nanoparticles were successfully synthesized via a simple and new wet

2 was obtained from wet synthesis method. TEM results showed that

2 nanoparticles was de-

2 nanoparticles increased

2 nanoparticles indicat-ed the structure of rutile phase with annealing process

2 nanoparticles in presence of nitric acid.

ACKNOWLEDGMENT

varamin pishva branch at Islamic Azad University for analysis and the discussion on the results.

REFERENCES

Mater. Sci. Eng. B, 96

J. Eur. Ce-ram. Soc., 26

Sains Ma-laysiana, 41

Am. J. Nanosci. Nanotech., 1

Nanoscale Res. Lett., 7

Open Mater. Sci. Journal, 4

Huang N.M., Sains Malaysiana, 39

Mater. Sci. Engineering B, 123

J.Appl. Phys., 96

Am. Mineral., 84 (1999),

Phys. Rev. B, 63

J. Chem. Soc. Faraday Trans, 94

J. Mater. Chem., 8

J. Phys. Chem. B, 104

Ency-clopedia of Chemical Technology, John Wiley & Sons, Inc.

J. Photochem. Photobiol. A. Chem., 84

Chem. Mater., 7

J. Mater. Sci., 34 (1999), 3721.

Cai S., J. Mater. Sci., 34 (1999) 2773.AICHE J.,

37

Langmuir, 16

J. Mater. Chem., 11

Figure 3: TEM images of the as-prepared TiO2 nano-

particles.


ABSTRACT

Keyword:


In recent years, there has been increasing interest in

for catalysts and supports, ceramics, inorganic mem-

2 has unique characteristics, such as weak acidity, basicity, redox and high thermal sta-

strongly depend on the particle size, the controlled and reliable preparation of nano-ranged materials represents

-

-

synthesis [6], sonocation [7] and polyol synthesis [8].

2 is widely used for gas

2 is particularly employed as catalyst car-

3

3)2.xH2 3) -Cl2.xH2 -

Preparation and Characterization of ZrO2/ZnO Nanocomposite under Ultrasonic Irradiation via Sol-gel Route

Shokufeh Aghabeygi1*, Maryam Zare-Dehnavi2, Ali Farhadyar3, Nazanin Farhadyar4

1 Assistant Professor, Department of Chemistry, East Tehran Branch, Islamic Azad University, Tehran, Iran2 Instructor, Department of Chemistry, East Tehran Branch, Islamic Azad University, Tehran, Iran

3 Ph.D., Agribusiness Department, Armenian State Agrarian University, IRAN4 Assistant Professor, Department of Chemistry, Varamin-Pishva Branch, Islamic Azad University, Varamin, Iran

1. INTRODUCTION


36

Int. J. Bio-Inorg. Hybd. Nanomat., Vol. 4, No. 1 (2015), 35-38 Aghabeygi S et al

um compounds have been used as well [16,17].Moreover, the sol-gel method allows for the homo-

geneous mixing of transition-metal cations at a mo-lecular level, which enhances the formation of poly-crystalline particles with special properties [18]. The

2 -

wide band gap semiconductor material which is used considerably for its catalytic, electrical, photoelectri-

using of ultrasonic irradiation has been employed of synthesis and sono-catalyst properties of many nano materials [21, 22].

We have been synthesized the binary nanocompos-

2 -trasonic probe is very effective in preparation process.

2. EXPERIMENTAL

3 2.2H2 --

then dropped into the precursor solution until pH of mixture was adjusted 9 and the white suspension of

2 was appeared. After that, the mixture was continuously stirred for 2 days then the tip of ultra-sonic probe was introduced into the mixture and it was

-

of H2 2

precursor solution under stirring. The pH of mixture was adjusted 9 by adding ammonium solution 2M

) was prepared and the produced gel was aged and stirring for 2 days, Then

2 gel and

2

then the mixture gels were irradiated by the probe of ultrasonic instrument for 2 h. The mixture was stirred

After drying at room temperature, the white precipi-


Surface and morphology of the synthesized nanocom-posite have been studied and the FESEM images are

Figure 1: FESEM images of ZrO2/ZnOnanocomposite.

37

Aghabeygi S et al Int. J. Bio-Inorg. Hybd. Nanomat., Vol. 4, No. 1 (2015), 35-38

2

3.2. XRD diffraction

2

shown in Figure 2. The distinct peaks corresponding to

2 are observed. It is concluded that both the materials exist in perfect crystalline phases and re-

2

2

2

The average particle size Dv of crystallites in the composite was also roughly calculated based upon the

-rer equation:

where: Dv is the “volume weighted” crystallite size = ¾ d (crystallite diameter) K is the “Scherer constant”

is , CuK

-mum) for a Gaussian shaped peak. The crystallite size

2 -tern is estimated to be 37 nm.

3.3. FT-IR analysis

2

shown in Figure 3, in the wave number range from -1 -1

can be attributed to symmetric and asymmetry stretch--

ion, .The peaks at 869 cm-1 were attributed to the vi-

cm-1

-1 resulted from bending vibration of the adsorbed H2

completely after Sol-gel synthesis. The wide peak at

KDvcos

Figure 2: XRD patterns of the ZrO2/ZnO nanocomposite

powder.

Figure 3: FT-IR spectra of the ZrO2/ZnO nanocomposite powder.

38

Int. J. Bio-Inorg. Hybd. Nanomat., Vol. 4, No. 1 (2015), 35-38 Aghabeygi S et al

-1

asymmetry stretching vibration of surface hydroxyl group.

4. CONCLUSIONS

2

a facile Sol-gel method using ultrasonic irradiation.

3 2.2H2 have been used as

2

-

2

2

2 -

-

2

obtained around 37 nm.

ACKNOWLEDGEMENT

The authors thank the research and technology section of Islamic Azad University East Tehran Branch.

REFERENCES

Surf. Coat. Tech., 204

Catal. Commun., 10

Combust. Flame, 144Mater. Sci.

Eng. B, 47 (1997), 171.

J. Colloid Interface Sci.,152

A.N., Mater. Lett., 26 (1996) 21.

Ceram. Int., 40 J. Mater. Res., 15

9. Apostolescu N., Geiger B., Hizbullah K., Jan

W., Appl. Catal. B, 62

Chem. Comm., 12Mater. Lett., 59

J. Nanopart. Res., 4

13. Jia Y., Hotta Y., Duran C., Sato K., Watari K., J.Cera, Soc. Japan, 113

J. Eur. Ceram. Soc., 20

SolidState Ionics, 123 (1999), 87.

J. Mater. Res., 15

17. Inoue M., Kominami H., Inui T., Res. Chem. In-termed., 24

J. Sol–Gel Sci. Technol., 42

J. Catal., 233198.

Lang-muir, 24

21. Huang M.H., Mao S., Feick H., Yan H.Q., Wu Sci-

ence, 292


ABSTRACT

Keyword:


Today nanotechnology is a matter of concern for all -

cations of these modern and new structures lead to a

of the most commonly used structures, which is of a great importance in nanotechnology, is carbon nano-

available from different sources [2]. These character-istics include thermal, chemical and structural proper-

main groups namely, zigzag, armchair and chiral struc--

ous applications, CNT is being increasingly applied in

A Theoretical Study of H2S and CO2 Interaction with the Single-Walled Nitrogen Doped Carbon Nanotubes

Mohsen Oftadeh1, Morteza Rezaeisadat2*, Alimorad Rashidi3

1 Ph.D., Chemistry Department, Payame Noor University, Tehran 19395-4697, I. R. of Iran2 M.Sc., Chemistry Department, Payame Noor University, Tehran 19395-4697, I. R. of Iran

3 Ph.D., Nanotechnology Group, Research Center of Tehran Oil Technique, Tehran, Iran

1. INTRODUCTION


Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 39-48 Rezaeisadat M et al

important industries which has been paying so much

and process industry. These structures are so notewor-thy due to having high values of length to diameter ratios, low density, homologous porosity and relative high structural stability in adsorption and storage of gases [8-11]. Crude natural gas which is generally extracted from gas wells and crude oil wells consist large amounts of methane, ethane, propane, butane and small amounts of heavier hydrocarbons. In addi-tion to the above mentioned compounds, some other impurities such as carbon dioxide and hydrogen sul-

of a great importance. These are named acidic gas-es because they react with water and result in acidic compounds. Existence of the acidic gases in the gas pipeline will result in the corrosion and erosion of pipelines [13]. H2S is one of the most harmful environ-mental pollutants. The crude natural gases are named sour gases due to having sulfur compounds specially H2

2 from H2S. The process

2 and H2S impurities are separated from the crude natural gas is called sweetening of sour gas. The most common used methods of sweetening are amine and Klaus methods [16].

Common theoretical methods consist of process simulations, and have relatively lower costs in com-parison to the experimental methods. Because nitroge-nized compounds have a long history in the adsorption and sweetening of sour gases, the present study sought to analyze and study different structures of single wall nitrogen doped carbon nanotubes (NCNT) in terms of stability, synthesis feasibility and their abundanc-es [17-21]. Having selected the proper structure, the interactions between H2 2 gases adjacent to NCNT and the pathway of adsorption on the nano-tubes were studied. Finally a comparison was done between the adsorption of acidic gases on NCNT and CNT [22].

2. COMPUTATIONAL METHOD

Due to the large number of constituent atoms, quan-

tum calculations in nanotube structures could be -

tive surveys were considered in order to accelerate these calculations, an average base set is used in this

to optimize the structures, stability of wave function, frequency, Energy correction to the basis set superpo-sition error (BSSE) and thermochemistry of calcula-tions, for the purpose of these calculations, Gaussian

In this article, nitrogen-doped single wall zigzag -

ses. The structure is drawn by HyperChem software. In order to prevent the effect of open end of single wall carbon nanotubes, both ends of the nanotubes were saturated by hydrogen atoms, to prevent any er-rors in complete optimization and frequency calcula-

of various CNT structures and the CNT adjacent to H2 2 gases which lead to interactional energy calculations for adsorption. Adsorption energy calcu-

(1)

From among the calculations, electrical conductivity calculation can be mentioned. Energy gap can be a cri-teria and indicator of electrical conductivity, which is

(2)

A less energy gap leads to a more electrical property. The value of enthalpy changes in the physical surface

(3)

In summary, the structures of NCNT, formed by the substitution of one nitrogen atom with one of the car-bon atoms in CNT, was analyzed. Then the interaction between acidic gases and NCNT was studied through selection of a proper structure.

ads (gas nanotube) gas nanotubeE E E E

E E E

298 f fH H H

Rezaeisadat M et al Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 39-48


3.1. Evaluation of different structures for NCNTWith regard to different positions of carbon atoms on nanotube and also energy of nitrogen ions in substitu-tion, six different structures were obtained for NCNT [26]. Among these structures, four main structures have been considered. These four structures are shown in Figure 1 for NCNT [27].

Structural optimization calculations are made for all

transformed properties such as Energies of Structures were analyzed and evaluated. Table 1 presents a sum-mary of some electron properties such as total ener-gy, relative energy, energy gaps and dipoles moment for NCNT and their differences with CNT. Nitrogen

because of this fact, some changes are found in bond length and bond angles in NCNT, and its structure is going to be changed from the initial structure. These changed and transformed structures, due to adding Ni-trogen atom, are called Bamboo like structures, which

are apparent especially in the structures of NCNT [27]. -

er the level of energy for a structure, the more stable is that structure, and it is considered as the main and optimum structure. According to Table 1, structure 1 has the lowest energy content, so it is the most stable structure. The highest level of energy and therefore the most unstable structure belongs to structure 3. In order

stability and synthesis feasibility, more detailed cal-

thermochemistry calculation. After calculation, there was no imaginary frequency, so these structures do not belong to transition states, and all of the structures are stable and feasible. In Table 2, a summary of results obtained from frequency calculations is provided. In empirical syntheses, obtained values for abundance of

--

percent belongs to other types of structure [28]. With

Figure 1: a) (Structure 1): nitrogen is located in up-edge position; b) (Structure 2): nitrogen is substituted be-

nitrogen is located in down-edge.

Energy Gap(eV)(Hartree)(Hartree)

Dipole Moment(Debye)Energy

Total Energy(Hartree)

Structure

Structure 1

3.31Structure 21.1172.16-1926.779Structure 3

-1926.797

Table 1:


regard to the high abundance of structure 2 and its low energy difference with structure 1, structure 2 is con-sidered as the main and optimum structure in order to evaluate the interactions between acidic gases and this structure.

3.2. Different positions of gases adjacent to NCNT

not possible to say exactly in what positions the gas-

internal or external wall of the CNTs, their acciden-tal movements, as well as the existence of different atoms such as carbon, nitrogen, sulfur and oxygen

will lead to different and various interactions between them [29]. So in order to have a detailed calculation all possible positions were considered. hydrogen sul-

make three main positions for interaction with the main axis of nano tube which pass through the cen-ter of nano tube. Figure 2-a depicts these positions as well as the three main interactions between H2S and

two main interaction positions as shown in Figure 2-b.

ΔG totΔH totΔU totStructure

Structure 1

-1926.3818Structure 2Structure 3

-399.3379Carbon DioxideNCNT & H2S

2

Table 2: Summary of results obtained from frequency calculation.

Figure 2: a) Three main positions of interactions between H2S and structure 2 of NCNT; b) Two main interaction positions

between CO2 and structure 2 of NCN.


axis will lead to the formation of the initial structure of

-

necessary to do a complete optimization by a proper method in order to obtain the balanced distances of gaseous molecules from nanotubes. Then, in order to evaluate the rotations and consider different interac-

was used which did not change the structure. There-fore, it was possible to rotate the gaseous molecule in proper directions and to calculate their related ener-gies for their positions.

2S data analyses

NCNT are shown in Figure 3. The main parameter in this evaluation is the corrected adsorption energy, Figure 3-a. The corrected adsorption energy includes adsorption energy and correction of energy obtained from the superposition error of the basis set (BSSE).

-

energy differences between different positions and en-ergy barrier in rotations are low. Figure 3-d shows the values of energy gaps for adsorptions in different posi-tions. Energy gaps are close in all the three positions, but in general the energy gaps for position 2 are less and the one for position 3 is more than other positions. So the electrical conductivity in position 2 is more than the other two positions. The changes in dipole moment has been shown in Figure 3-e. Generally the value of dipole momentum for position 2 is more than the other positions. Data obtained from the changes in the distance of H2S gas from NCNT, is provided in Figure 3-f. The most stable energy belongs to a bal-

difference from the obtained value for complete opti-

Figure shows the potential energy curve used in the

geometrical optimization of molecule. A useful com-parison is conducted between adsorption energy of H2S on CNT and NCNT, which is provided in Figure 3-c. Adsorption is more stable in NCNT than in CNT.

from internal rotation of the gas molecule in NCNT are shown in Figure 3-b. Adsorption of H2S in external wall of NCNT is more effective in comparison to its adsorption in internal wall.

3.4. CO2 data analyses

adsorption energy calculations for different positions of carbon dioxide adjacent to NCNT. The lowest lev-el of adsorption energy belongs to position 2 which

due to the change in the interaction of oxygen and ni-trogen in different rotations. For both of the positions the most stable condition was obtained when there was an interaction between carbon and nitrogen. In the rotations of both positions, no negative stable adsorp-

from the energy gaps. The lowest energy gap is in

of the interactions between oxygen and nitrogen at-

of angles in position 1 are more than dipole moments

2 and NCNTs. the lowest energy found in the balanced distance equals to

provides a comparison between adsorption energy on

2 2 is more stable in NCNTs than in CNT. According to Fig-

2 inside the NCNTs is often neither effective nor useful.

2S and CO2 adsorptionsDoes NCNT as a separator catalyst show a better re-action to the separation of H2 2 from sour gases in the sweetening process? The answer to this question is obtained from the analysis and evalu-ation of the comparison between adsorption energy of


the desired gases. For H2 2 the best adsorp-

a comparison between the adsorption energy of both gaseous molecules on NCNTs resulting from the rota-tion. Generally, the adsorption of H2S on NCNT is

2. There is a negligible 1 kcal/mol difference between the adsorption energies for both gases. A comparison between the adsorption energies of these two gaseous molecules on normal

gases on CNT are weak and unstable. Therefore, ex-istence of nitrogen in the structure of CNT leads to an increase in the adsorption of H2 2 gases. The

2 2 is -

cess is thermodynamically desirable.

3.6. Electrostatic potential Electrostatic potential or electric potential energy sur-

Figure 3: The changes of corrected adsorption energy versus the rotations of H2S at different positions on a) the external; b)

the internal walls of the structure 2 of NCNT; c) The comparison between adsorption energies of H2S on external wall of CNT

and NCNT; the changes of d) energy gap; e) dipole moment versus the rotations of H2S at different positions on the external

walls of the structure 2 of NCNT and f) The changes of adsorption energy of H2S vs. the distance of the molecule from NCNT.


Figure 4: The changes of corrected adsorption energy versus the rotations of CO2 at different positions on a) the external; b)

the internal walls of the structure 2 of NCNT; c) The comparison between adsorption energies of CO2 on external wall of CNT

and NCNT; The changes of d) energy gap; e) dipole moment versus the rotations of CO2 at different positions on the external

walls of the structure 2 of NCNT and f) The changes of adsorption energy of CO2 vs the distance of the molecule from NCNT.

Figure 5: The Comparison between adsorption energies of H2S and CO2 on a) NCNT and b) CNT.


around the system. This knowledge instruct to identify the probable positions for interaction or/and reaction.

-ed in Figure 6 which shows the positive electrostatic potential dominates around the tube and the minimum electrostatic potential presents on the nitrogen atom. So this area has more willing for interaction with the acidic gases from the positive electrostatic potentials zoon. This zoon is from the hydrogen atoms for H2S

2.

electron density ( 2 ) and electron Hamilton (H) have been collected in Table 3 [31]. By

-cian it can be predicted the weak interactions between both H2 2 gases with the NCNT. In other words because of low values for and H for the two

2/NCNT the interaction is electro-

static, and about H2S/NCNT because of more negative

2/NCNT, the interac-tion is Vander Waals.

3.8. Density of states

CNT and NCNT has been presented in Figure 7-a. This

between the valance bond and conduction bond is not zero and states that both structures are semiconduc-

ev, respectively, which put on for the semiconductor ranges. In the present of nitrogen atom in the tube the

-

So it is expected that NCNT has less electric conduc-tivity than CNT. Fig 7-b shows that the present of the acidic gases on the CNT nanotubes causes to decrease

the conduction bond. In addition the differences be-

Figure 6: A feature of the EPES for bare NCNT obtained from MultiWFN.

SystemAIM

ρ ∇2ρ HNCNT gas type name

H2S/NCNTC H (3, -1)C H (3, -1)

2/NCNT N C (3, -1)C (3, -1)

Table 3: Results of atoms in molecule (AIM) calculations about the critical points for H2S/NCNT and CO2/NCNT systems.


the gases. Because of the similar differences for the

2/CNT and H2S/CNT they can’t be used

has been shown in Figure 7-c which differs from the gas/CNT systems. All of the three systems have simi-lar energy gap and the differences between them are

and conduction bond is about similar. So it can’t be

the gases is higher than NCNT.

4. CONCLUSIONS

gases on NCNT is more desirable in comparison to

existence of Nitrogen in the structure of CNT leads to an increase in the adsorption of H2 2. Ad-

sorption of H2 2 gases on the external wall of NCNT is better than their adsorptions on the inter-nal wall. Adsorption of H2S gas on the external wall

2 on it. With regard to data obtained from natural bonding orbital

electrostatic, and there are no bonds between gaseous atoms and NCNT. Adsorption of both gases is desir-able in terms of thermodynamic data. Corrections of energy are negligible based on the superposition error of basis set for both gases. It is suggested to consider correction values of energy for a better evaluation of adsorption energies. The frontier orbitals are similar in

2 2S leads to a

2

and H2S gases on the NCNT does not obviously affect

ACKNOWLEDGEMENT

This research was in full supported by a grant from

Figure 7: Density of states (DOS) for the CNT and NCNT bare and the adsorbed gases systems.


REFERENCES

Carbon Nanotubes, Synthesis, Structure, Properties and Applications, Berlin: Springer.

Science, 280Lieber C.M., Acc. Chem.

Res., 35Compos. Sci.

Technol., 61Mater. Sci. Eng. Rep., 43

Nanotechnology, 18

7. Yang S.H., Shin W.H., Kang J.K., Small, 4

Compos. Sci. Technol., 65

Carbon, 39

J. Phys. Chem., 107

11. Shirvani B.B., Shirvani M.B., Beheshtian J., Had-J. Iran. Chem. Soc., 8

J. Chem. Eng., 56 (1978), 197.

Water Environ. Res., 71

Natu-ral Gas

Gas and Liquid Sweetening,

-chler T., Carbon, 48

CVD synthesis of nitrogen doped carbon nanotubes using iron pentacarbonyl as catalyst, M.Sc. in the Faculty of Science, Uni-versity of the Witwatersrand, WITF.

Phys. Status Solidi,B 247

Nitro-gen-Containing Carbon Nanotubes: A Theoretical Approach

Nitrogen and Boron Doping in Carbon Nanotubes, Ameri-

Study of Adsorption Properties of O2, CO2, NO2 and SO2 on Si-doped Carbon Nanotube Using Density Func-tional Theory, International Conference on Ap-

23. M.J. Frisch, G.W. Trucks, H.B. Schlegel, G.E. -

gomery, T. Vreven, K.N. Kudin, J.C. Burant, J.M. Millam, S.S. Iyengar, J. Tomasi, V. Barone, B.

ExploringChemistry with Electronic Structure Methods,

Physical Chemistry

A.V., Nordlund K., Nucl. Instr. and Meth. Phys. Res. B, 228

Di-oxygen Adsorption and Dissociation on Nitrogen Doped Carbon Nanotubes from First Principles Simulation

Appl. Phys. Lett., 831222.

Nanotech-nology, 13

Int. Nano Lett., 3

31. F. Biegler-Konig, J. Schonbohm, -


ABSTRACT

3

Keyword:


Ceramics with general formula A B or AmB 3m

represent cubic perovskite structures. They are called

because of their properties such microwave dielectric [1], high relative permittivity, and low temperature

Sr Nb has been investigated for diamagnetic insu-

synthesis of Sr Nb nanomaterials such as reaction

pyrolysis, and calcinations [7]. In the present study, a hydrothermal route was employed successfully for the

Low Temperature Hydrothermal Synthesis and Characterization and Optical Properties of Sr5Nb4O15 – Nb2O5 Nanocomposite

Shahin Khademinia1, Mahdi Behzad2*, Abdolali Alemi3, Mahboubeh Dolatyari4

1 Ph.D., Department of Chemistry, Semnan University, Semnan 35351-19111, Iran2 Associate Professor, Department of Chemistry, Semnan University, Semnan 35351-19111, Iran

3 Professor, Department of Inorganic Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz, Iran4 Associate Professor, Laboratory of Nano Photonics & Nano Crystals, School of Engineering-Emerging

Technologies, University of Tabriz, Tabriz, Iran

1. INTRODUCTION


Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 49-54 Behzad M et al

synthesis of nanostructured Sr Nb 2 com-

3)2, Nb2 -rials. To the best of our knowledge, there is no report on the synthesis of nanostructured Sr Nb 2

-

and particle morphology were investigated, and the band gap energy of the as-prepared nanocomposites samples was initially estimated from UV-Visible spec-

-composites were also studied.

2. EXPERIMENTAL

3)2, Nb2

were of analytical grade and were obtained from com-mercial sources (Merck, Germany) and were used

1

and S2 were synthesized via hydrothermal method in

-many) using CuK radiation. The morphology of the

-sion scanning electron microscope (Hitachi FE-SEM

--

sor 27 (Bruker Corporation, Germany). Cell parame-

5Nb4O15- Nb2O5

nanocomposites

3)2 (Mw = 211.62 g mol-1) and

2-1)

1 and S2

-

cooled to room temperature by water immediately. The prepared powder was washed with distilled water

-spheric conditions and a cream like powder was col-lected for further analyses.


3.1. Powder X-Ray diffraction analysisNb 2

nanocomposites samples are reported in Figures 1 and -

sis of Sr Nb -etry with Cu-K radiation. The results showed that the

Figure 1: PXRD patterns of the S1. The bars show the

Bragg's positions for a) Sr5Nb4O15, b) orthorhombic Nb2O5

and c) monoclinic Nb2O5.

Behzad M et al Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 49-54

pattern had two Sr Nb and Nb2 as main phases. Sr Nb structure was detected with hexagonal crys-

space group [1]. Two different crystal structures were observed for Nb2 in both (S1) and (S2 -ly orthorhombic and monoclinic crystal structures. Nb2

orthorhombic and monoclinic crystal structures. It

Sr Nb phase formation compared to Nb2 phase

synthesis condition, there is still a mixture of two phases including Sr Nb and Nb2 . The measured

Nb nanomaterials [1]. According to Nb

phase formation compared to Nb2

it is clear that there is an optimization in Sr Nb

Compared to the nanomaterials of the hydrothermally synthesized Sr Nb (S1), the diffraction lines in the

Nb 2 nano-composites (S2

therefore to the higher d values. So, using the peak

1

1 -lated via Bragg’s equation. So there is an expansion in the unit cell according to the calculated data.

(S1) and (S2), respectively. The data showed that with changing the synthesis rout, the cell parameters for (S2) were larger than those of (S1). So there should be an expansion in the unit cell. It is in agreement with the interplanar spacing data calculated via Bragg’s equation.

Figure 3 shows typical FESEM images of the hydro-thermally synthesized Sr Nb 2 nanocom-

1). From the typical FESEM images of S1

3a and b, it was found that the morphology of the

Figure 2: PXRD patterns of the S2. The bars show the

Bragg's positions for a) Sr5Nb4O15, b) orthorhombic Nb2O5

and c) monoclinic Nb2O5.

Table 1: Cell parameter data for samples 1 and 2.

Cell parameter Standard Sample [3] Sr Nb (S1) Sr Nb (S2)

a 9.9136

bc


-thermally synthesized Sr Nb 2 nanocom-

2). FESEM images of S2

-tures from the very small plates as petals crossed each

Figure 3: FESEM images of S1.

Figure 4: FESEM images of S2.

Behzad M et al Int. J. Bio-Inorg. Hybr. Nanomater., Vol. 4, No. 1 (2015), 49-54

-

the images showed that the size ranges of the obtained materials were nearly non-homogeneous. Also, Figure 3d showed that the thickness size of the very small

S1 and S2 -tained on the samples S1 and S2 show main absorp-

-1

-1, respectively, that are characteristic for the synthesized Sr NbNb2

-1 are assigned to monoclinic Nb2 and the -1 is attributed to orthorhombic

Nb2

of both orthorhombic and monoclinic Nb2 in the synthesized nanocomposite that is in agreement with

-1 are attributed to the bending mode of H2

-1 is as-

Figure 6 shows the UV-Vis spectra of the synthe-sized nanocomposites. The absorption peak positions in both spectra suggest that these materials are wide band gap semiconductors. It is clear in Figure 6a that

band gap is about 3.22 eV that is smaller than that of

S1. It is not surprising to observe the difference in the optical property because these two specimens have different constituting crystalline phases. However, it is clear that the absorption spectrum shown in Figure

2 that is because of the very large Nb2 /Sr Nb

-sorption spectra. However, the band gaps are different from the calculated data in this work [16].

4. CONCLUSIONS

In this work, Sr Nb 2 nanocomposites were synthesized successfully via hedrothermal meth-

successfull. FESEM images showed that the as-syn-

1) and two kind

2

of the synthesized nanocomposites were also investi-gated to further support the synthesis of the nanocom-

nanocomposites were also investigated.

Figure 5: FTIR spectra of S1 and S2.

Figure 6: UV-Vis spectra of S1 (a) and S2 (b).


REFERENCES

Mat.Lett., 57

Mater. Sci. Eng. B, 131

3. Weiden M., Grauel A., Norwig J., Horn S., Steg-lich F., J. Alloys and Compounds., 218

C.Y., J. Europ. Ceram. Society, 27

Progress in solid state chem., 36Ceram. Interna-

tional, 357. Urabe H., Hisatomi T., Minegishi T., Kubota J.,

Farad. Dis., 1768. Ikeya T., Senna M., J. Non-Cryst. Solids, 105

Mater. Lett., 58

Phys. Chem. Chem. Phys., 5

11. Jehng J.M., Wachs I.E., Chem. Mater., 3 (1991),

J. Sol-Gel Sci. Technol., 56

Y.S., J. Phys. Chem. C, 111

Chem. Sci. Trans., 2

Catal.Today, 174

16. Chen D., Ye J., Chem. Mater., 21

International Journal of Bio-Inorganic Hybrid Nanomaterials

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