Cu/CeO2 catalysts for reverse water gas shift reactions: the effect of the preparation method

Abstract

The reverse water gas shift reaction is one of the most prospective CO₂ utilization approaches. Cu has excellent selectivity for CO and CeO₂ is rich in surface oxygen vacancies for CO₂ activation. These unique properties are often used to develop efficient Cu/CeO₂ catalysts in RWGS. In this paper, Cu/CeO₂ is prepared by plasma-induced micro-combustion. The effect of the subsequent calcination after micro-combustion on the structure and catalytic property is systemically studied. Because of the mild temperature of micro-combustion, highly dispersed Cu species load on the surface of CeO₂ for the catalyst without calcination (Cu/CeO₂-mc). During calcination, the highly dispersed Cu species form two kinds of species, Cu–Ce solid solution structure and small CuO clusters (Cu/CeO₂-mcc). The Cu–Ce solid solution effectively enhances the generation of oxygen vacancies, which improves the adsorption and activation of CO₂. The catalytic performance of Cu/CeO₂-mcc thereby is superior to Cu/CeO₂-mc in RWGS. In situ diffuse reflectance infrared fourier transform spectroscopy analysis demonstrates that the formate pathway is the main mechanism of RWGS. CO₂ adsorbed on the surface of Cu/CeO₂-mcc mainly forms bidentate species. While monodentate generates on the surface of Cu/CeO₂-mc. And decomposes to CO easier than , thus Cu/CeO₂-mcc exhibits excellent catalytic properties. This work provides a new approach for structural modulation of catalysts with excellent catalytic performance in RWGS.