Synergically engineering Cu+ and oxygen vacancies in CuMn2O4 catalysts for enhanced toluene oxidation performance

Herein, a simple preparation strategy was developed to enhance the oxygen replenishment capacity of CuMn2O4 catalysts by synergically engineering the Cu+ and oxygen vacancies (VO). The surface physicochemical properties of the CuMn2O4 catalysts were regulated by the annealing temperature and solvent, and the effect of two different VO (VO from Cu+-VO−Mn3+ and Mn2+-VO−Mn3+ were denoted as VO(CM) and VO(MM), respectively) on oxygen activation were studied. The results demonstrated that the Cu+ and VO synergically promoted the low-temperature reducibility, adsorbed oxygen species, and the oxygen replenishment of CuMn2O4 catalysts. Especially, the abundant Cu+ cations and VO(CM) greatly promoted the transformation of O2 → O2− → O−. The prepared CuMn2O4-EG-350 catalyst exhibited excellent catalytic performance (T90 = 208 °C), and the reaction route of toluene oxidation over CuMn2O4-EG-350 was confirmed as follows: toluene-benzyl alcohol-benzoate-maleic anhydride-CO2 and H2O. The Cu+-rich CuMn2O4-EG-350 catalyst with an efficient synthetic strategy is a promising industrial catalyst for toluene elimination.