Methanol oxidation on an ink type electrode using Pt supported on high area carbons

Abstract

Methanol oxidation was investigated on the following Pt catalysts: bare Pt electrode, Pt covered by nafion (R) film, and pt catalysts supported on high area carbons in the form of an ink. The reaction was carried out using slow linear potential sweep and potentiostatic steps. Active surface area of Pt particles was estimated from hydrogen desorption charge on cyclic voltammograms. The influence of Nafion film, Pt loading, type of carbon support, and methanol concentration were studied. No influence of Nafion (R) film on kinetic parameters of methanol oxidation was found. Tafel slope on smooth Pt was found to be about 90 mV dec(-1), while on supported Pt catalysts time depende(n)t values between 140 and 90 mV dec(-1) were estimated from the potentiostatic decays by using data between 0.5 and 5 min. Specific activity was slightly dependent on Pt loading with flat maximum at about 20%, Pt. Activity of Pt/SAB catalyst was two to three times higher than that of Pt/BP and Pt/XC-72 catalysts.