Promoting effects of indium doped Cu/CeO2 catalysts on CO2 hydrogenation to methanol

Abstract

Cu-Based materials have been extensively reported as promising catalysts to convert CO₂ into value-added chemicals and fuels. Herein, we report In-promoted Cu/CeO₂ catalysts (CuCeIn5 and CuCeIn10) prepared by a surfactant-assisted co-precipitation method and applied in the CO₂ hydrogenation to methanol. Structural characterization indicated that catalysts were formed in an inverse configuration, consisting of small single-domains of CeO₂ particles (5–7 nm) deposited over large Cu particles (55–70 nm). The presence of highly dispersed indium induced a decrease in CeO₂ particle size, increasing the interface areas that acted as CO₂ adsorption sites, as observed by spectroscopic and temperature-programmed analysis. During CO₂ hydrogenation, indium-promoted catalysts led to a remarkable increase of 66% in methanol selectivity compared to the unpromoted system. In situ DRIFTS revealed the formate route as the preferred route for methanol formation. After temperature, pressure, and space velocity optimization through chemometric tools, the In-doped Cu/CeO₂ (CuCeIn5) catalyst achieved a methanol selectivity of 99.3% with no CO formation.