Copper-doped ZnO-ZrO2 solid solution catalysts for promoting methanol synthesis from CO2 hydrogenation

Copper-doped ZnO-ZrO2 solid solution catalysts were synthesized via co-precipitation for promoting CH3OH synthesis via hydrogenation of CO2. Various testing methods were applied to investigate the effect of various copper contents on the catalysts. The catalytic performance was evaluated by a fixed bed reactor. XRD, HRTEM and Raman spectra collectively indicated that a ZnO-ZrO2 solid solution catalyst with 3% Cu had a higher Cu dispersion, while the H-2-TPR results confirmed that a catalyst with 3% Cu had more Cu active sites under low temperature H-2 pretreatment. When the copper content increased to 5% and 10%, the catalyst showed a better Cu crystallinity and a worse Cu dispersion, which could have a negative effect. Therefore, the CO2 conversion and methanol yield with a 3% CuZnO-ZrO2 catalyst at 5 MPa, 250 degrees C and 12 000 ml/(g h) increased by 8.6% and 7.6%, respectively. Moreover, the CH3OH selectivity and catalytic stability of the solid solution catalyst were better than those of the traditional CZA catalyst.