Catalytic oxidation of ethyl acetate and toluene over Cu–Ce–Zr supported ZSM-5/TiO2 catalysts

Abstract

Copper–cerium–zirconium catalysts loaded on ZSM-5/TiO₂ (denoted as CCZ/Z and CCZ/T) were prepared and characterized in this investigation and the catalytic behaviors of VOCs over the catalysts were determined. It is shown that the low-temperature activities of ethyl acetate and toluene oxidation over the CCZ/T catalyst are obviously higher than that over the CCZ/Z catalyst. Compared with CCZ/Z, the force between the metal oxides and the support TiO₂ is weaker and TiO₂ can provide some lattice oxygen. The greater number of oxygen vacancies, together with more Cu⁺ species in CCZ/T increases the mobility of atomic oxygen anions, which can inhibit by-product formation and enhance catalytic activity effectively. Moreover, the larger pore size of CCZ/T is beneficial for the diffusion of reactants and products. The analysis of intermediate species and the Mars–van Krevelen mechanism well explain the superior oxidation performances of ethyl acetate and toluene on CCZ/T. Both CCZ/Z and CCZ/T show superior stability for the catalytic removal of ethyl acetate and toluene at their complete conversion temperatures, which contribute to the positive effects of the Ce–Zr promoters on the copper species and support.