Insight into the correlation between Cu species and methanol selectivity from CO2 hydrogenation over Cu-based catalyst

Abstract

The pre-activation of Cu-based catalysts is an important step to fully develop their catalytic potential. The production of active species (Cu+ and Cu0) which play the active site role generally occurs in the activation stage by reducing from Cu2+. Herein, the Cu+/Cu0 ratio of CuZnOAl2O3 (CZA) catalysts was adjusted using different activation atmospheres and the relationship between Cu+/Cu0 ratio of the catalyst and methanol selectivity from CO2 hydrogenation was investigated in detail. Combined with X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), in situ diffuse reflectance infrared Fourier transformation spectroscopy (DRIFTS) characterization, etc. and experimental results, it was observed that the selectivity of methanol was obviously relied on the Cu+/Cu0 ratio of CZA catalyst. This work provides theoretical guidance and feasible scheme to rationally design and optimize the required catalysts.