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

Abstract

A bifunctional catalyst (CZ x S/Zn-HZSM-5) with tunable oxygen vacancy was prepared by coupling ceria-zirconia solid solution (CZ x S) and zinc-modified HZSM-5 zeolite (Zn-HZSM-5). The characterization results indicated that the formation of CZ x S by insertion of zirconia (Zr) atoms into cerium oxide (CeO 2 ) could generate more oxygen vacancy due to the structural distortion. With the increasing of Zr content, the oxygen vacancy concentration on the surface of CZ x S 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 CZ x S/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 CZ 4 S/Zn-HZSM-5 with the highest oxygen vacancy concentration. Highlights• A CZ x S with tunable oxygen vacancy is synthesized by inserting the Zr into CeO 2 .• The reaction begin with the activation of CO on the oxygen vacancy of CZ x S.• CZ x S/Zn-HZSM-5 contribute to the matching between CO activation and alkylation.

Recent Progress of Ga-Based Catalysts for Catalytic Conversion of Light Alkanes

“…With the introduction of metal components, which can dehydrogenate light alkane into olefins first, the conversion of alkane can be improved to a large extent. Pt [41,42], Ga [43], Zn [44,45], Fe [46,47], etc., have been reported to efficiently build bifunctional catalysts with HZSM-5 as a catalytic cracking active component.…”