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Methanol Oxidation at Platinum in Alkaline Media: A Study of the Effects of Hydroxide Concentration and of Mass Transport
Author(s) -
Rus Eric D.,
Wakabayashi Ryo H.,
Wang Hongsen,
Abruña Héctor D.
Publication year - 2021
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.202100087
Subject(s) - hydroxide , chemistry , methanol , inorganic chemistry , cyclic voltammetry , platinum , voltammetry , diffusion , adsorption , electrochemistry , electrode , analytical chemistry (journal) , catalysis , chromatography , organic chemistry , physics , thermodynamics
The hydroxide ion concentration dependence of the methanol oxidation reaction at Pt was studied using microelectrode voltammetry and rotating disk electrode voltammetry. Both methods suggest that the rate of methanol oxidation is limited by hydroxide mass transport at low hydroxide concentrations, while it is inhibited by hydroxide adsorption at high concentrations. It was possible to shift from the transport‐limited regime to the inhibitory regime by varying the bulk concentration of hydroxide or by varying mass transport to the electrode. Rotating ring‐disk electrode voltammetry was employed to qualitatively assess changes in the diffusion layer pH. The results indicated a decrease in the surface pH during methanol oxidation, as expected, but also that the pH reached a steady state during hydroxide transport limited methanol oxidation.