Cu/SiO2 derived from copper phyllosilicate for low-temperature water-gas shift reaction: Role of Cu+ sites

Abstract

Copper phyllosilicate supported over silica was prepared with ammonia evaporation method. Compared with the catalyst synthesized with conventional impregnation method, this novel catalyst showed a much higher activity and stability towards low-temperature water-gas shift reaction. Various characterization methods indicated the Cu nanoparticle in the catalyst had a superb small diameter around 3 nm, co-existent with abundant Cu+ sites. Based on the analysis via CO-adsorption, DRIFTS and in-situ mass spectrum, it was proved that CO could be adsorbed on Cu+ strongly and Cu+ acted as the active sites for CO activation. The reaction mechanism with dual active sites prevented the competitive adsorption of H2O and CO onto Cu0 sites, thereby improving the catalytic activity and stability.