Urea-assisted preparation of N-CNO x catalysts for enhanced low-temperature catalytic oxidation of toluene

In this study, a variety of CoNi oxide (N-CNO x ) catalysts were synthesized by treating MOF-74 with urea, demonstrating excellent performance in catalyzing the oxidation of toluene. Specifically, the produced 1.0 N-CNO x exhibited outstanding catalytic activity in a Plasma co-catalysis system (T 90  = 251 ℃), which is 32 ℃ lower than that of CNO x (T 90  = 283 ℃), along with strong stability and water resistance during prolonged operation and exposure to water vapor. Experimental results showed that heat treatment with urea enhanced the catalyst’s redox capacity by promoting the formation of high-valent Co and Ni species and increasing the amount of reactive oxygen species on its surface. This paper proposes a novel technique for developing efficient toluene catalytic oxidation catalysts through urea treatment, providing a theoretical foundation for the design of non-precious metal catalysts.