A robust ceria-based high entropy oxide catalyst for efficient propane oxidation

Efficient elimination of volatile organic compounds using cost-effective catalysts at low temperatures remains a significant challenge. Herein, a novel Ce-based high entropy oxide (Ce-HEO) with a fluorite structure was successfully fabricated via a simple citric acid sol-gel approach, which was systematically compared against Cebased catalysts doped with individual transition metals (Co, Mn, Ni, Cu, Fe; designated CeM). Characterization analyses suggest that metal doping in CeO2 restrains its grain growth, induces abundant oxygen vacancies, augments specific surface area, and enhances low-temperature reducibility. The Ce-HEO catalyst benefits from a synergistic cooperative interaction among its multiple metallic components, leading to optimal reducibility and an abundance of oxygen vacancies. It demonstrates markedly higher propane oxidation performance compared to CeNi, CeCu, and CeFe catalysts, and is nearly on par with CeCo and CeMn catalysts. Though showing slightly lower activity than CeCo, Ce-HEO exhibits much better anti-sintering performance and water resistance. Moreover, Ce-HEO possesses excellent stability and durability, maintaining its activity after four catalytic cycles and a 24-h continuous test. This study contributes to the development of effective catalysts for light alkane removal and provides guideline for the design of HEO materials.