Enhanced Methanol Oxidation Using Polymer-Incorporated Rough Pt Electrodes

We study the methanol oxidation reaction (MOR) on veryrough Ptsurfaces. We develop an electrodeposition method yielding Pt electrodeswith high roughness factors (R (f) > 80),controlled by varying the electrodeposition time or by polymer codeposition.These rough electrodes exhibit a linear MOR response at potentialsup to 1.4 V versus RHE, in contrast to the hysteretic behavior reportedin numerous prior studies. This effect is found in both acidic andbasic electrolytes. Studies show that increased surface roughnessincreases the surface concentration of methanol, thereby inhibitingthe formation of Pt oxides at higher potentials, which are known topoison the subsequent methanol oxidation activity. The potential atwhich methanol oxidation poisoning occurs is found to be logarithmicallydependent on the bulk methanol concentration, with varying slopesin acidic and basic media. The origin of different sensitivities inbasic relative to acidic electrolytes is found to be the result ofdifferent reaction orders with respect to methanol. This study providesmethods to enhance the rate of organic molecule oxidation at electrodesurfaces that can be applied to both electrosynthesis and direct methanolfuel cell applications.