Electro-catalytic oxidation of cellulose at Au electrode by Ari Ivaska
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Transcript of Electro-catalytic oxidation of cellulose at Au electrode by Ari Ivaska
Electro-catalytic oxidation of cellulose at Au electrode
Ari Ivaska, Yasuhito Sugano, Rose-Marie Latonen, Marceline Akieh and Johan Bobacka
Process Chemistry Centre, Åbo Akademi UniversityBiskopsgatan 8, FI-20500 Turku, Finland
ACES: European Dimension21.5. 2015
ChemSusChem, 2014, 7, 2240-2247
Molecular structure of cellulose
Polysaccharide: β(1→4) linked D-glucose units
Insoluble in pure water but can be dissolved in 1.3 M NaOH
CVs of cellulose at Au electrode in 1.3M NaOH
CVs of cellulose at Au electrode in 1.3M NaOH
CVs of cellulose at Au electrode in 1.3M NaOH
CVs of cellulose at Au electrode in 1.3M NaOH
CVs of cellulose at Au electrode in 1.3M NaOH
Mass change during potential cycling in1.3 M NaOH
Scan rate 10 mV/s
Sample treatment
Electrolysis
Original cellulose sample (solid)
Dialysis
Centrifugation
Water insoluble fraction
Water soluble fraction
Dialysis
Centrifugation
Cellulose solution sample (liquid)
Water insoluble fraction
Water soluble fraction
Dissolution in 1.3 M NaOH
Vacume-freeze-drying
Vacume-freeze-drying
SEM images of cellulose samples
original regenerated water insolubleafter electrolysis
water solubleafter electrolysis
TEM images of water-insoluble cellulose after electrolysis
Au nanoparticles ≈ 4 nm
Proposed mechanism
a: initial state: dissolved cellulose in alkaline solutionb: adsorption of OH- ions to the electrode and cellulose molecule approaching the Au-OH site on the electrode surfacec: oxidation of cellulose at the electroded: simultaneous desorption of the oxidation product from the surface and further oxidation of cellulose at the revealed electrode surfacee: desorption of adsorbed OH- ions from the electrode surface.
Conclusions
Cellulose can be oxidized at Au surface Adsorption of OH- ions at the Au surface is of
importance Two type of material is formed during
electrolysis:
- water soluble: containing caboxyl groups
- water insoluble: containing Au nanoparticles
Electroanalysis in Ireland, Electroanalysis na h’Éireann
NIHE, 10-12.6.1986
Meeting in Dublin 5.5.2014
Previous arrival to Dublin
ICSM-2014, Turku, Finland
Thank you for your attention
CVs of 1 % cellulose solution in 1.3 M NaOH
Different potential ranges