Atomistic picture of electronic metal support interaction and the role of water

Abstract

Single atom catalysis (SAC) represents an emerging area of heterogeneous catalysis but faces challenges related to the low density of active sites and poor thermal stability. In this work, we present new fundamental insights into the nature of electronic metal support interactions (EMSI) coupled with cation exchange, which yield high density of atomically dispersed noble metals on defect-free terraces of cation-terminated reducible oxides. On well-ordered Co₃O₄(111) films, the mechanism involves temperature-controlled substitution of surface Co²⁺ and sub-surface Co³⁺ cations by Pt²⁺ and Pt⁴⁺ species, respectively. The cation exchange with Co²⁺ is coupled with the partial reduction of Co₃O₄(111), while the cation exchange with Co³⁺ involves the charge disproportionation within the Pt species. In the presence of co-adsorbed water, the Pt⁴⁺ species are stabilized at the surface in the form of triaqua complexes.