Synthesis Gas Conversion to Lower Olefins over ZnCr‐SAPO‐34 Catalysts: Role of ZnO−ZnCr2O4 Interface

Abstract

AbstractThis work reports that the ZnO−ZnCr2O4 interface was constructed by tailoring the Zn/Cr ratio and the role of ZnO−ZnCr2O4 interface in activating CO molecule for the synthesis of lower olefins over a tandem catalyst was studied. A lower olefins selectivity of 71 % at a CO conversion of 34 % was achieving on Zn1Cr1&SAPO‐34. The presence of ZnO−ZnCr2O4 interface effectively reduces the activation energy of CO hydrogenation (from 51.8 kJ/mol to 33.6 kJ/mol) and subsequently leading to the triple increase of intrinsic activity. In situ DRIFTS and XPS studies demonstrate that the better catalytic activities of Zn1Cr1 catalyst are related to the presence of ZnO−ZnCr2O4 interface, which provides more oxygen vacancy sites for CO adsorption and activation. In this sense, the Zn1Cr1 catalyst with ZnO−ZnCr2O4 interface is more active than the simple physical mixture of ZnO and Cr2O3 catalyst separately and Zn1Cr2 catalyst. This work provides fundamental insights for a rational design of Zn−Cr based catalysts and even other heterogeneous catalysts by constructing oxide‐oxide interface.