DFT study on the effect of electric field on the adsorption of methanol on Pd(1 1 1)

Abstract

Density functional theory (DFT) calculations for the methanol oxidation reaction (MOR) has attracted much more attention than ever before, since the mechanism of methanol dehydrogenation is very important in direct methanol fuel cell (DMFC). Herein, methanol adsorption on Pd(111) with different electric field intensity (0.000, 0.0010, 0.0025 and 0.0050 au) were studied with DFT calculations. The results showed that methanol may adsorb on the Pd(1 1 1) either through the methyl or the hydroxyl of methanol in the absence electric field, since the two adsorption configurations share the similar adsorption energy. However, along with the increase of the electric field intensity, the angles formed by C-O bond axis and Pd(1 1 1) became gradually smaller, and it is only 1.9° when the electric field intensity value is 0.0050 au for the methyl case; while it kept at 35±5° for the hydroxyl case. The methanol molecule was not activated in the reported electric field.