Activation reconstructing CuZnO/SiO2 catalyst for CO2 hydrogenation

Abstract

Cu-based catalyst is widely employed for methanol synthesis from syngas or CO2 hydrogenation. Catalyst activation is usually considered as a preliminary step for subsequent reaction. The influence of the activation process on the catalytic performance and how the physic-chemical properties of the catalyst are modulated are still not clear. Herein, the activation of the CuZnO/SiO2 (CZS) catalyst is studied in depth through adjusting the reduction gas velocity. The results indicate that the different activation processes reconstruct the physic-chemical properties of the CZS catalyst. After 40 h stability test, the catalytic activity decreases as the following order of CZS-120 > CZS-60 > CZS-0 catalysts (CZS-0, CZS-60 and CZS-120 catalysts represented that CuZnO/SiO2 catalysts were pretreated with reducing gas speeds of 0 mL/min, 60 mL/min and 120 mL/min at 10 vol%H2/N2, respectively.). Combined with the analysis of XRD, TEM, N2O chemisorption, H2-TPR, XPS, H2-TPD, CO2-TPD characterization and experimental results, the optimized activation plays a vital role in increasing significantly the dispersion of Cu species of the catalyst and improving the Cu-ZnO interaction. This strategy provides theoretical guidance and feasible scheme for optimizing the performance of Cu-based catalyst.