Periodic density functional theory(DFT) calculations are presented to describe the adsorption and decomposition of CH 3 OH on Ru(0001) surfaces with different coverages, including p(3×2), p(2×2), and p(2×1) unit cells, corresponding to monolayer(ML) coverages of 1/6, 1/4, and 1/2, respectively. The geometries and energies of all species involved in methanol dissociation were analyzed, and the initial decomposition reactions of methanol and the subsequent dehydrogenations reactions of CH 3 O and CH 2 OH were all computed at 1/2, 1/4, and 1/6 ML coverage on the Ru(0001) surface. The results show that coverage exerts some effects on the stable adsorption of CH 3 O, CH 2 OH, and CH 3 , that is, the lower the coverage, the stronger the adsorption. Coverage also exerts effects on the initial decomposition of methanol. C-H bond breakage is favored at 1/2 ML, whereas C-H and O-H bond cleavages are preferred at 1/4 and 1/6 ML on the Ru(0001) surface, respectively. At 1/4 ML coverage on the Ru(0001) surface, the overall reaction mechanism can be written as 9CH 3 OH→3CH 3 O+6CH 2 OH+9H→6CH 2 O+3CHOH+18H→ 7CHO+COH+CH+OH+26H→8CO+C+O+36H.
Density functional theory calculations have been performed to investigate methanol oxidation to formic acid on PtAu(111) and Pt(111) surfaces with and without CO in alkaline media. The calculated results show that the pre-adsorbed CO species promotes almost every step involved in the oxidation of methanol on PtAu(111) and Pt(111) surfaces, which is similar to that observed on a Au(111) surface. These findings may be attributed to the relatively high stability and strong basicity of the OH species induced by the adsorption of CO, and the enhanced ability to strip the H atoms.
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