Enhanced Methanol Oxidation on Strained Pt Films

We report a systematic investigation into the effect of strain on the electrocatalytic activity of films of Pt. We use an electroless deposition process to deposit the Pt onto sputtered Au substrates and characterize their structural and electrochemical properties. We found a direct correlation between the rate of methanol oxidation and the fractional surface coverage of methanol on the compressively strained catalyst surfaces. The fractional methanol surface coverage, Θ_M, varied on the Pt surfaces with values ranging from 20.5 to 61.7%, depending on the level of compressive strain. A compressive strain of about ε = -0.110% resulted in a high fractional surface coverage of 61.7% with highest peak current density for methanol oxidation of 0.46 mA cm^-2 and earliest peak potential of 0.67 V vs Ag/AgCl. As the absolute value of the compressive strain increased, the fractional surface coverage and peak current density for methanol oxidation decreased. Therefore, the adsorption of molecular methanol was controlled by the strain generated in the Pt films, resulting in higher fractional surface coverage and ultimately enhancing the rate of oxidation of methanol. (Graph Presented).