Oxygen vacancies in Cu/TiO2 boost strong metal-support interaction and CO2 hydrogenation to methanol

How to efficiently activate and convert CO2 through hydrogenation to value-added chemicals is a major challenge. This work investigates the role of oxygen vacancy (Ov) in the Cu/TiO2 catalysts, which are promising for this reaction. The TiO(2-x)support was pre-reduced in high-pressure H-2 gas at different tem-peratures to generate Ov with different concentrations. Cu/TiO2-x-500 with TiO2 pre-reduced at 500 & DEG;C showed much higher CO2 conversion and CH3OH selectivity than the other Cu/TiO2 catalysts. The Ov in the reduced TiO2 induced a strong metal-support interaction (SMSI) between Cu and TiO2 at relatively low temperatures. Although the SMSI caused partial covering of the Cu nanoparticles by TiO2-x, the Ov in the newly formed interface could facilitate the activation of the CO2 molecules and promote the forma-tion of the proper reaction intermediates for methanol formation. Various characterizations, including DFT calculations, revealed the detailed structural evolution of CO2 to methanol on the Cu/TiO2 catalyst, and it follows the Formate pathway.(c) 2022 Elsevier Inc. All rights reserved.