Molybdenum-based oxygen carrier for chemical looping oxidative dehydrogenation of isobutane

Abstract

Compared with steam cracking, oxidative dehydrogenation of isobutane to produce isobutene has advantages, but its application is limited by capital intensive air separation needed to provide O2. A chemical looping oxidative dehydrogenation strategy for isobutane to isobutene is proposed to tackle this problem, in which the oxygen carrier provides lattice oxygen. The synthesis of the oxygen carrier from the perspective of electronic structure and metal–oxygen bond strength is highly desirable to enhance the performance of the chemical looping oxidative dehydrogenation of isobutane. Herein, the electronic structure and metal–oxygen bond strength of a Mo-based oxygen carrier are regulated by doping Zn, V and Mg. The results show that Mg0.2Zn0.8Mo0.45V0.55Ox with 35% isobutane conversion and 82% isobutene selectivity is superior to MoO3, ZnMoOx and ZnMo0.45V0.55Ox. It indicates that the electronic structure and metal–oxygen bond strength via doping Zn, V and Mg are responsible for the promoted performance of Mg0.2Zn0.8Mo0.45V0.55Ox. This study provides important insights for the oxygen carrier design and optimization through regulating electronic structure and metal–oxygen bond strength.