Dependence on Under-Coordinated Pt at the Surface of Layered PtTe2 in the Decomposition of Methanol

Abstract

Abstract Decomposition of adsorbed methanol (CH3OH) was activated on under-coordinated Pt (denoted as Ptuc), produced by removing Te, at layered PtTe2 surface. Both dehydrogenation and C-O bond scission occurred, resulting in the formation of intermediates CHxO* (x = 2, 3; * denotes adsorbates) and CHx* (x = 1, 2) and ultimately the production of gaseous molecular hydrogen, methane, water and formaldehyde. We observed a great reaction probability (> 90 %) on the Ptuc sites and a catalytic selectivity dependent on the Ptuc concentration. Approximately 60 % of the methanol decomposed to CHxO* and 35 % to CHx* at small Ptuc concentrations (£ 10 %); nevertheless, with increased Ptuc concentration (> 10 %), both the probability of decomposition to CHxO* and the production of gaseous formaldehyde were selectively decreased. We propose the characteristic reactivity at small Ptuc concentrations arises from both the triangular positioning and varied degrees of oxidation of surface Ptuc.