Methanol Oxidation on Pt3Sn(111) for Direct Methanol Fuel Cells: Methanol Decomposition

PtSn alloy, which is a potential material for use in direct methanol fuel cells, can efficiently promote methanol oxidation and alleviate the CO poisoning problem. Herein, methanol decomposition on Pt3Sn(111) was systematically investigated using periodic density functional theory and microkinetic modeling. The geometries and energies of all of the involved species were analyzed, and the decomposition network was mapped out to elaborate the reaction mechanisms. Our results indicated that methanol and formaldehyde were weakly adsorbed, and the other derivatives (CHxOHy, x = 1–3, y = 0–1) were strongly adsorbed and preferred decomposition rather than desorption on Pt3Sn(111). The competitive methanol decomposition started with the initial O–H bond scission followed by successive C–H bond scissions, (i.e., CH3OH → CH3O → CH2O → CHO → CO). The Bronsted–Evans–Polanyi relations and energy barrier decomposition analyses identified the C–H and O–H bond scissions as being more competitive than the C–O bond scissio...