Investigating the role of undercoordinated Pt sites at the surface of layered PtTe₂ for methanol decomposition

Transition metal dichalcogenides, by virtue of their two-dimensional structures, could provide the largest active surface for reactions with minimal materials consumed, which has long been pursued in the design of ideal catalysts. Nevertheless, their structurally perfect basal planes are typically inert; their surface defects, such as under-coordinated atoms at the surfaces or edges, can instead serve as catalytically active centers. Here we show a reaction probability > 90 % for adsorbed methanol (CH₃OH) on under-coordinated Pt sites at surface Te vacancies, produced with Ar⁺ bombardment, on layered PtTe₂ — approximately 60 % of the methanol decompose to surface intermediates CH_xO (x = 2, 3) and 35 % to CH_x (x = 1, 2), and an ultimate production of gaseous molecular hydrogen, methane, water and formaldehyde. The characteristic reactivity is attributed to both the triangular positioning and varied degrees of oxidation of the under-coordinated Pt at Te vacancies.