CrO /Ce1−Zr O2 for chemical looping propane oxidative dehydrogenation: The redox interaction between CrO and the support

Propane dehydrogenation is an attractive alternative for propylene production to petroleum-based routes. However, overcoming deactivation and toxicity of catalysts in propane direct dehydrogenation (PDH), and over oxidation in oxidative dehydrogenation (ODHP) remain challenging. Here, a chromium-based catalyst supported on a Ce-Zr solid solution is constructed for chemical looping oxidative propane dehydrogenation (CL-ODHP). A dual modulation of oxygen species by Zr doping was unraveled by characterizations and DFT calculation: the oxygen of surface CrOx was constrained while the oxygen mobility of the Ce-Zr support was promoted. Based on these properties, the interaction between surface CrOx and the support further enables an oxygen “donor–acceptor”, which potentially functions as in situ activation and regeneration of redox CrOx species as well as blockage of non-selective oxygen released from the Ce-Zr support. The optimized material (7.5Cr/Ce0.8Zr0.2O2) achieves propane conversion up to 50% and propylene yield of 31% at 600 °C, and has the lowest Cr content among previously reported Cr-based catalysts that have comparable performance. These results provide insights for the design of highly active and selective redox catalysts for chemical looping as a reaction engineering strategy for the upgrading of propane dehydrogenation processes.