Theoretical Insights into the Effect of Solvation and Sublayer Ru on Pt-Catalytic CH3OH Oxidation Mechanisms in the Aqueous Phase
2018
Ou, Lihui
A systematic periodic DFT study of CH₃OH oxidation on Pt(111) that involved the effect of solvation and sublayer Ru has been performed. Both the thermochemistry and the kinetics of all of the elementary reaction steps are addressed, and the reversible potentials of various elementary reaction steps during key intermediates CHO and CO formations are predicted; thus a detailed potential energy surface showing the interconversions of the various intermediates is presented. The effect of solvation and sublayer Ru on CH₃OH oxidation mechanisms is revealed. Simultaneously, the origin of solvent effect on CH₃OH oxidation mechanisms is also illustrated systematically through geometry configurations and electronic structure analysis, which can partially explain some experimental observations in UHV and electrochemical interfaces, especially the difference between the initial CH₃OH oxidation pathways and the adsorbed residues that poisoned the pure Pt surface and impeded the performance of DMFCs. The present study will provide a deeper understanding for CH₃OH electro-oxidation mechanisms. It is also hoped that insights gained from such investigations will eventually lead to the development of improved DMFCs anode catalysts. Although the absence of electric charge on the potential energy surface will influence the accuracy of the calculations and the present results are not always quantitatively correct, the conclusions in trends are expected to be reasonably accurate qualitatively.
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