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