Uncovering the synergy between gold and sodium on ZrO2 for boosting the reverse water gas shift reaction: In-situ spectroscopic investigations

Abstract

CO2 conversion to CO via the reverse water-gas shift (RWGS) reaction is a promising source of syngas for subsequent synthesis of liquid fuels and chemicals. Herein, we present the synthesis of catalysts containing Au supported on hydroxylated Na-modified ZrO2, with Au amounts ranging from 0.05 to 1 wt%. Systematic investigations reveal the formation of cooperative Au/Na sites at the interface. These sites cooperate synergistically to activate CO2 and generate a high surface density of carboxylate-like species, which serve as highly active intermediates for CO formation. It was found that the RWGS reaction on the catalyst with low Au loading proceeds mainly via a carboxylate pathway, with bidentate formate acting as spectators. At higher Au loading, the bidentate formate pathway contributes somewhat to CO formation alongside the carboxylate pathway. Based on temporal analysis of products, we emphasize the significant roles of H2 spillover and the metal-support interface in the RWGS reaction.