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

Abstract

Abstract This work reports that the ZnO−ZnCr 2 O 4 interface was constructed by tailoring the Zn/Cr ratio and the role of ZnO−ZnCr 2 O 4 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 Zn 1 Cr 1 &SAPO‐34. The presence of ZnO−ZnCr 2 O 4 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 Zn 1 Cr 1 catalyst are related to the presence of ZnO−ZnCr 2 O 4 interface, which provides more oxygen vacancy sites for CO adsorption and activation. In this sense, the Zn 1 Cr 1 catalyst with ZnO−ZnCr 2 O 4 interface is more active than the simple physical mixture of ZnO and Cr 2 O 3 catalyst separately and Zn 1 Cr 2 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.