1 research outputs found
Methanol Electro-Oxidation on the Pt Surface: Revisiting the Cyclic Voltammetry Interpretation
Methanol
is a promising fuel for direct methanol fuel cells in
portable devices. A deeper understanding of its electro-oxidation
is needed for evaluating electrocatalytic performance and catalyst
design. Here we provide an in-depth investigation of the cyclic voltammetry
(CV) of methanol electro-oxidation. The oxidation peak in backward
scan is shown to be unrelated to residual intermediate oxidation.
The origin of the second oxidation peak (I<sub>f2</sub>) is expected
to the methanol oxidation on Pt–O<sub><i>x</i></sub>. Electrochemical impedance spectroscopy coupled with CV reveals
the origin of CV hysteresis to be a shift in the rate-determining
step, from methanol dehydration to OH adsorption by water dissociation,
induced by a change in Pt surface coverage with oxygenated species.
The peak ratio between forward oxidation peak current (I<sub>f</sub>) and backward oxidation peak current (I<sub>b</sub>), which is I<sub>f</sub>/I<sub>b</sub>, is not related to the degree of CO tolerance
but to the degree of oxophilicity indeed