The dependence of high catalytic performance on the tunable oxygen vacancy in the CZxS/Zn‐HZSM‐5 bifunctional catalyst for alkylation of benzene and syngas

Abstract

AbstractA bifunctional catalyst (CZxS/Zn‐HZSM‐5) with tunable oxygen vacancy was prepared by coupling ceria–zirconia solid solution (CZxS) and zinc‐modified HZSM‐5 zeolite (Zn‐HZSM‐5). The characterization results indicated that the formation of CZxS by insertion of zirconia (Zr) atoms into cerium oxide (CeO2) could generate more oxygen vacancy due to the structural distortion. With the increasing of Zr content, the oxygen vacancy concentration on the surface of CZxS increased as well, which reached a maximum for a Zr/Ce ratio of 4 and then decreased by further increase of Zr content. The dependence of oxygen vacancy concentration in the CZxS/Zn‐HZSM‐5 bifunctional catalyst on their catalytic performance in the benzene alkylation with syngas was further investigated. The result exhibited that the oxygen vacancy was the site for CO activation, and the more oxygen vacancy, the better catalytic performance. The best catalytic activity, with a CO conversion of 33%, the benzene conversion of 30% and the total toluene and xylene selectivity of 92% was obtained over the bifunctional catalyst CZ4S/Zn‐HZSM‐5 with the highest oxygen vacancy concentration.