Mechanisms investigation of the WGSR catalyzed by single noble metal atoms supported on vanadium oxide clusters

Abstract

The redox and carbonyl mechanisms of the water gas shift reaction (WGSR) catalyzed by the single noble metal (NM) atoms of Ru, Rh, Pd, Ag (from the 4d row) and Os, Ir, Pt, Au (from the 5d row) supported on vanadium oxide cluster ion V2O6+ have been firstly investigated through the density functional theory (DFT) calculations. Natural population analysis (NPA) shows NMs possess positive charges in the model systems and usually act as reactant molecule trapper and an effective electron store to accept or release electrons. The carbonyl mechanism avoiding the oxygen vacancy (Ov) formation and directing NM‐H bond cleavage is strongly preferred over the redox mechanism. Our computations identified single‐atom catalysts (SAC), especially RhV2O6+ and PdV2O6+ exhibit improved overall catalytic performance because of the lower rate‐control step activation barriers via the associate carbonyl mechanism. This work aims to provide some detailed insights into the effects of NM in bimetallic oxide clusters for WGSR at a molecular level, and serves as a starting point for further theoretical studies on the mechanisms of related SAC catalytic reactions.