New Insights into Electrocatalysis of Nitrogen Reduction ... · NH3 s-1cm-2) Rate of of NH 3 )mol...
Transcript of New Insights into Electrocatalysis of Nitrogen Reduction ... · NH3 s-1cm-2) Rate of of NH 3 )mol...
New Insights into Electrocatalysis of Nitrogen Reduction to Ammonia
Alex Schechter
Department of Chemical Sciences Ariel University, Israel ([email protected])
Experimental Setup
Collected Ammonia in the Acid Trap and the Electrolyte
The electrochemical cell
Quantification of Ammonia using Indophenol and Nessler’s method
Indophenol method Nessler’s method
Ammonia Sodiumhypochlorite
Salicylicacid
Indophenolmethod
Voltammetry of N2 Reduction on PGM catalysts in alkaline pH
VulcanXC-72
Ru/C
Pt/C
RuPt/C
PGM-PlatinumgroupmetalRT,ambientpressure,1MKOH
Applied Potential
)E / V vs. RHE(
Rate of ammonia
)mol s-1cm-2(
Efficiency of ammonia produced
(%)
0.123 3.0×10-10 13.20.023 6.12×10-10 4-0.077 6.37×10-10 1.15-0.177 5.95×10-10 0.75-0.277 5.45×10-10 0.35
The Effect of Applied Potential and Temperature
Electrochemical ammonia synthesis at RuPt/C at 50 °C
NRR Catalysts Comparison Catalyst Rate of of NH3
(gNH3 s-1cm-2)Rate of of
NH3
)mol s-1cm-2(
Applied Potential (RHE)
Faradaic Efficiency (%)
Reference
Pt-electrode 1.9× 10−8 1.1× 10−9 1.6 V (Fuel cell configuration)
0.1 Sci. Rep. 3 (2013) 1145
Ru-electrode 3.57 × 10−10 2.1 × 10−11 -1.02 V (Vs. Ag/AgCl)
0.9 Chem. Commun. (2000) 1673–1674.
Fe2O3-CNT 6.11×10-10 3.57× 10−11 -2.0 (Vs. Ag/AgCl) 4.5 Angew.Chem. Int.Ed. 2017, 56,2699 –2703
Au nanorods 4.57×10-10 2.6 × 10−11 -0.2 V 4 Adv. Mater. 29 (2016) 1700001
Au nanoparticles on CeOx-RGO support
2.3×10-9 1.3 × 10−10 -0.2 V
10.1 Adv. Mater. 29 (2017) 1700001
Au subnano- clusters on TiO2
5.9×10-9 3.4 × 10−10 -0.2 V
8.1 Angew. Chemie - Int. Ed. 40 (2001) 1061–1063.
RuPt/C 7.25×10-9 4.2× 10−10 -0.077 V
3.0 Present work
RuPt/C 1.08×10−8 (50° C) 6.3×10-10 -0.077 V 3.8 Present work
Mechanism of Electrochemical Nitrogen Reduction Reaction Nitrogen reduction reaction via a) dissociative and b) associative mechanism.
On-Line Mass Spectrometry Analysis During N2 Electrolysis
After CO adsorption; there was no ammonia formation
Ammonia Formation under CO Adsorption on RuPt/C
N2 Electrolysis -0.1 V
Cycle1
CyclicVoltammetry
Cycle2
LinearSweepVoltammetry
Ammonia Formation under CO Adsorption on Pt/C and Ru/C LS-Voltammogram Ru/C N2 Electrolysis Ru/C at -0.1 V
LS-Voltammogram Pt/C N2 Electrolysis Pt/C at -0.1 V
Proposed Cooperative Reaction Mechanism
Acknowledgments
Sponsors
• Ministry of commerce (KAMIN prog.)
• ISF- P.M. Ministry via INREP program
• Ministry of Energy and Water
• Ministry of Defense
• Ministry of Environmental Protection
GroupMembersPostdocs• Dr.HananTeller• Dr.OlgaKrichevsky• Dr.SubramanianPalaniappan• Dr.RameshSingh• Dr.ManJunathaR.• Dr.AleksKarajichPhDStudents• Mrs.OritBen-Zazon• SrikanthKolagatla• HenFriman• RoopathyMohan• DiwakarKashyap• AntonyCyrilMscStudents• Mrs.MietalGor• Mrs.YuliaYufa• Mr.VictorMoltenan• Miss.ShaniOchanuna• Mr.YuvalMoshe• Mr.AsafCohen• Mrs.EfratTzor• Mr.ShnmuelRozenfeld• Mr.EtiPitossi• Mr.LeaOaknin• Mr.RazMasas• Mr.YakirNagar• Mr.MikeSasoon-Engineer
Collaborations • Dr. Daniel Nessim-BIU • Prof.-Yoed Tzur-Technion • Dr. David Zitoun-BIU • Dr. Amir Nathan-TAU • Dr. Rivka Cahan-AUC • Prof. Zeev Gross –Technion • Prof. Idit Avrahami-AUC • Prof. Steve Dubowsky -MIT • Prof. Edward Bormashenko –AUC • Prof. Haya Korenwitz-AUC • Prof. Aharon Gedanken-BIU • Dr. Flavio Grynszpan-AUC