Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Rrde Studies of Glycerol Electro-Oxidation
T2 - Local pH Variation and Oscillatory Dynamics
AU - Zülke, Alana
AU - Perroni, Paula
AU - Machado, Eduardo Giangrossi
AU - Varela, Hamilton
PY - 2017/7/7
Y1 - 2017/7/7
N2 - Using Ptdisk-Ptring electrodes we investigated glycerol electro-oxidation in alkaline media under both conventional and oscillatory conditions. The estimation of pH variation was done by polarizing the ring electrode at 100mV vs. RHE. The local depletion of OH- (variation in hydronium concentration) during oxidative steps at the disk is seen by the cathodic currents at the ring associated with hydrogen evolution, whose equilibrium potential (Nernstian potential) is shifted due to its well-known pH dependence. Typical voltammetric experiments at 20mV.s-1 in hydrodynamic conditions reveal ΔpH of around 1 unit. Higher rotation rates yielded lower peak currents. Under oscillatory conditions the situation is rather complicated as rotation of the electrode impacts on the critical population of intermediates required to sustain oscillations. It was only possible to obtain reproducible oscillatory dynamics under stationary conditions and pH variations seem not detectable by this technique.
AB - Using Ptdisk-Ptring electrodes we investigated glycerol electro-oxidation in alkaline media under both conventional and oscillatory conditions. The estimation of pH variation was done by polarizing the ring electrode at 100mV vs. RHE. The local depletion of OH- (variation in hydronium concentration) during oxidative steps at the disk is seen by the cathodic currents at the ring associated with hydrogen evolution, whose equilibrium potential (Nernstian potential) is shifted due to its well-known pH dependence. Typical voltammetric experiments at 20mV.s-1 in hydrodynamic conditions reveal ΔpH of around 1 unit. Higher rotation rates yielded lower peak currents. Under oscillatory conditions the situation is rather complicated as rotation of the electrode impacts on the critical population of intermediates required to sustain oscillations. It was only possible to obtain reproducible oscillatory dynamics under stationary conditions and pH variations seem not detectable by this technique.
U2 - 10.1149/07711.1643ecst
DO - 10.1149/07711.1643ecst
M3 - Journal article
VL - 77
SP - 1643
EP - 1650
JO - ECS Transactions
JF - ECS Transactions
SN - 1938-6737
IS - 11
ER -