Mg enhanced the performance of Cu/ZnO/ZrO2 for CO2 hydrogenation to methanol and the mechanism investigation

Abstract

Optimizing the microstructure of copper-based catalysts for CO2 hydrogenation to methanol is an attractive and widely reported strategy, but there are still certain barriers to improving both carbon dioxide conversion rate and methanol product selectivity. Herein, Cu/ZnO/ZrO2/MgO (CZZ1-xMx) catalysts were synthesized by co-precipitation method for CO2 hydrogenation to methanol. Furthermore, the structural features and reaction processes were systematically characterized by XRD, TEM, nitrogen adsorption/desorption, H2-TPR, CO2-TPD and in-situ DRIFT. The results showed that Mg species optimized the microstructure of the catalyst, increased the dispersion of active species and constructed appropriate basic sites. This further enhanced the capture of reactive species and improved the CO2 hydrotreating to methanol reaction performance, which was accompanied by a simultaneous increase in CO2 conversion and methanol yield. It could be convinced that the highest space time yield (STY) of methanol (305.3 gMeOH kgcat−1 h−1) was obtained at 220 °C, WHSV = 18,000 mL gcat−1 h−1 and 3 MPa (XCO2 = 7.28%, SMeOH = 71.8%) for the optimized CZZ0.8M0.2 catalyst, which exhibited twice the CO2 conversion than Cu/ZnO/ZrO2. This work elaborated a scheme for the preparation of efficient methanol catalysts. providing reference for the research of CO2 hydrogenation to methanol process.