Highly efficient CO2 hydrogenation to methanol over Cu–Ce1-xZrxO2 catalysts prepared by an eco-friendly and facile solid-phase grinding method

Abstract

In this study, a series of Cu–Ce1-xZrxO2 (x = 0, 0.2, 0.5, 0.8, 1) catalysts were prepared by an eco-friendly and facile solid-phase grinding method. The effect of different Ce/Zr molar ratios on the performance of Cu–Ce1-xZrxO2 catalysts for CO2 hydrogenation to methanol was investigated. The results showed that the Cu–Ce0.5Zr0·5O2 catalyst had the best catalytic performance, with CO2 conversion of 15.2 % and methanol yield of 7.5 % at GHSV = 3600 mL/(gcat·h)); when GHSV was increased to 20,000 mL/(gcat·h), the space-time yield of methanol reached 270.8 gCH3OH/(kgcat·h). X-ray diffraction (XRD), scanning electron microscope (SEM), N2 adsorption-desorption, N2O chemisorption, X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction by H2 (H2-TPR), and temperature programmed desorption (H2-TPD, CO2-TPD) techniques were used to characterize the catalysts, and the higher reactivity of Cu–Ce0.5Zr0·5O2 can be attributed to more Cu0 species, defect oxygen and basic sites. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTs) results revealed that the hydrogenation of CO2 to methanol occurred through the formate intermediate pathway. This work proposed an eco-friendly and facile method for the preparation of high-performance Cu-based catalysts and the systematic study provided a deep insight for the development of high-performance Cu-based catalysts for methanol synthesis from CO2 hydrogenation.