Synthesis Gas Conversion to Lower Olefins over ZnCr‐SAPO‐34 Catalysts: Role of ZnO−ZnCr<sub>2</sub>O<sub>4</sub> Interface
Xiaoyue Wang, Ruiwen Cao, Kuo Chen, Congcong Si, Hongyan Ban, Peng Zhang, Fanhui Meng, Litao Jia, Jie Mi, Zhong Li, Congming Li
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.