Mechanistic Aspects of Methanol Electro‐Oxidation Reaction through Cyclic Voltammetry: Is It Correct to Blame Carbon Monoxide for Catalyst Poisoning?
Pooja S. Deshpande, Vijay R. Chaudhari, B. L. V. Prasad
Abstract
Many previously unknown facts have been revealed by the reinvestigation of the cyclic voltammetric (CV) response of the methanol oxidation reaction (MOR) in acidic medium using Pt/C as the electrocatalyst. Systematic CV analysis clearly suggests that the peak during the cathodic scan in the CV of MOR belongs mainly to electro‐oxidation of the carbon monoxide (CO) species, which is not truly adsorbed on the electrode surface and hence has less possibility to poison the electrode surface. Interestingly, an additional peak is observed in the anodic scan at higher scan rates and the results suggest that this peak is associated with surface‐confined electrochemical processes related to the oxidative desorption of leftover CO. This clearly highlights the necessity to relook at the notion of correlating the ratio of the peak currents in the anodic versus cathodic directions to CO poisoning, which is routinely used for the evaluation of the electrode performance in MOR. Through simple but accurate CV experiments, this report clearly brings out the important criteria that should be looked into while evaluating the electrocatalyst performance in the MOR process.