The Thermal Kinetics of Methanol Oxidation on Pt/MWCNT Electrocatalysts in Alkaline Media

Abstract

In this study, the thermal electrooxidation of methanol on a Pt/MWCNT catalyst was examined in alkaline media across the temperature range of 298-363 K. The investigation utilized cyclic voltammetry (CV), quasi-state polarization, and electrochemical impedance spectroscopy (EIS) methods to explore the kinetics of the methanol electrooxidation reaction (MEOR). At elevated temperatures, the kinetics of methanol electro-oxidation on the Pt/MWCNT catalyst within an alkaline solution (1.0 mol/L KOH) were notably accelerated compared to room temperature. This acceleration can be attributed to the reduced methanol dehydrogenation reaction at relatively low temperatures. The Tafel slopes experienced changes as the temperature increased. These variations in Tafel slopes are likely linked to alterations in the rate-determining step of the MEOR as a function of temperature. The EIS outcomes revealed a decrease in charge-transfer resistance as temperature increased. This phenomenon is associated with the interplay between interfacial and diffusion impedances, as well as the surface roughness of the highly dispersed electrode surface.