Fabrication of ZnZrO2@Al2O3@SAPO-34 tandem catalyst for CO2 conversion to hydrocarbons

An exploration into the influence of interfacial characteristics between ZnZrO(2)and SAPO-34 on CO2 hydrogenation to lower olefins was conducted. This was achieved by fabricating ZnZrO2@Al2O3@SAPO-34 tandem catalyst based on a chemical coating strategy. Physically blended ZnZrO2/SAPO-34 and hydrothermally coated ZnZrO2@SAPO-34 were employed as references for exploring the correlation between interfacial characteristic and catalytic performance. The results showed that ZnZrO2@SAPO-34 fabricated via hydrothermal coating method exhibited inferior catalytic performance resulting from the inactivation of ZnZrO2 active components after hydrothermal treatment. However, post pre-coating modification by Al2O3 of ZnZrO2 prevented the deactivation of ZnZrO2 active components, as well as facilitating the formation of chemically interfacial phase between ZnZrO2 and SAPO-34 with encapsulated structure based on micro-mesoporous system and rich acidbase active centers. The collective contributions aroused by the role of Al2O3 are the crucial to enhanced catalytic performance of ZnZrO2@Al2O3@SAPO-34 tandem catalyst. Under 3 MPa, 3500 ml g(-1).h(-1) and 380 degrees C reaction conditions, CO2 hydrogenation on ZnZrO2@Al2O3@SAPO-34 tandem catalyst exhibited a high C-2-C-4(75% C-2(-)-C-4(-), 20% C-2(0)-C-4(0)) selectivity of 95% with the CH4 selectivity of 3% among hydrocarbon products at the CO2 conversion of 21% and 45% selectivity of CO by-product. Compared with ZnZrO2@SAPO-34, the selectivity of C-2-C-4 over ZnZrO2@Al2O3@SAPO-34 tandem catalyst increased by 55%. In addition, this work also opens a new window for designing the excellent bifunctional tandem catalysts for the other applications.