High-Entropy Spinel Oxide as Highly Effective Catalysts for the Catalytic Combustion of Volatile Organic Compounds

Abstract

Volatile organic compounds (VOCs) such as propylene represent a major category of pollutants threatening environmental safety and human health. Catalytic combustion is a promising solution, yet designing highly active and stable catalysts remains a challenge. In this work, a high-entropy spinel oxide (Ni0.2Mg0.2Cu0.2Mn0.2Co0.2)Al2O4 was synthesized via a sol–gel method. The results demonstrated that the (Ni0.2Mg0.2Cu0.2Mn0.2Co0.2)Al2O4 calcined at 700 °C exhibited uniform elemental distribution and a high specific surface area of 110.2 m2/g. The catalyst exhibited a higher concentration of surface-reactive oxygen species and moderate C3H6 adsorption energy. For the catalytic combustion of propylene (C3H6), the catalyst achieved superior activity, a low apparent activation energy of 64.76 kJ/mol, and it maintained stable catalytic performance over 400 h without obvious deactivation. DFT calculations indicated that the high-entropy sample has the lowest oxygen vacancy formation energy. This study provided a promising strategy for designing high-performance non-noble metal catalysts for propylene elimination, highlighting the significant potential of high-entropy spinel oxides in industrial catalytic applications.