Diffusion-restricted electrodeposition of platinum on solid carbon paste for electrocatalytic oxidation of methanol

Synthesis and Characterization of Platinum-Cerium Oxide Nanocatalysts for Methanol Oxidation

“…At the potential E = 0.03 V (the peak potential of the negative-going scan on CVs) the spectrum changes dramatically, exhibiting pseudo-inductive behavior. Based on literature data, 38,41,42 this indicates a reaction mechanism with one adsorbed intermediate, although in case of methanol oxidation, many intermediates likely exist, but the turnover rate of all but one intermediate is very fast. The spectrum at the potential E = 0.18 V (the peak potential for the positive potential direction scan on CVs) does not extend further than the second quadrant.…”

“…electrical double layer (so-called "true") capacitance (f → ∞), R 1 is the charge transfer resistance, CPE 1 is a constant phase element representing mixed adsorption kinetics on the inhomogeneous electrode surface, R 2 is the mass transfer resistance and C 2 is the adsorption capacitance. Circuit B has been used previously 38,42,43 to fit impedance data of methanol oxidation. In circuit B, R S is the uncompensated solution resistance, CPE 1 is a constant phase element, representing double layer capacitance (while taking into account the inhomogeneity of the electrode surface), R 1 is the charge transfer resistance for the methanol oxidation step, R 2 and L 1 are the charge transfer resistance and inductance due to the oxidation of the adsorbed CO layer, respectively.…”

“…In circuit B, R S is the uncompensated solution resistance, CPE 1 is a constant phase element, representing double layer capacitance (while taking into account the inhomogeneity of the electrode surface), R 1 is the charge transfer resistance for the methanol oxidation step, R 2 and L 1 are the charge transfer resistance and inductance due to the oxidation of the adsorbed CO layer, respectively. 42 In case of solutions containing MeOH, Circuit B is applied at E ≥ 0.03 V.…”