LAUSR

Abstract Direct conversion hydrogenation of CO2 to hydrocarbons is a highly attractive but challenging method for obtaining value-added lower olefins with low CO selectivity. In this work, composites of SAPO-34 and ZnO-ZrO2 were successfully fabricated via hydrothermal coating and physical blending methods, respectively. Characterization results indicated that the composite phase together with coexisting acidic and basic sites and distinct micro-mesoporous structure was obtained without overly tight contact between the two active compounds in the physically blended composite. As a result the selectivity for lower olefins was 70% among all hydrocarbon products while CO selectivity was around 41%. Then, H2 reduction on ZnO-ZrO2 precursor was performed to explore the electronic properties of the physically blended composite. Interestingly, the CO by-product was significantly suppressed from 41% to 27% by the alterations of the acid and basic sites resulting from electronic property tuning of Zn and Zr sites during H2 reduction at 500 °C. The synergetic effect of composite phase, suitable electronic property tuning, large number of acidic-basic sites and distinct micro-mesoporous structure all made essential contributions to the enhanced catalytic activity for direct CO2 conversion, the superior selectivity for lower olefins and less amount of CO by-product over ZnO-ZrO2/SAPO-34 composite.