Low temperature benzene oxidation over copper-silver catalyst: roles of copper oxide and silver on cerium-zirconium mixed oxide

Catalytic oxidation is a promising way to remove volatile organic compounds (VOCs) given its low energy consumption, low operating cost, high removal efficiency, and wide applicability. Platinum group metals (PGMs) are widely employed as active components for catalytic VOC oxidation. However, extensive efforts are underway to replace the PGMs with inexpensive materials for commercial applications. In this study, we prepared a new non-PGM benzene oxidation catalyst by incorporating copper and silver in cerium-zirconium mixed oxide (CZCuAg). The synergetic effects of the catalytic components enabled complete benzene oxidation at low temperature, below 200 ℃. The structural characterizations of the catalysts, and in-situ diffuse reflectance infrared Fourier transform analyses of benzene oxidation over the catalysts, revealed that the CZCuAg catalyst consisted of copper (II) oxide and metallic silver, which mainly provide benzene adsorption and benzene oxidation, respectively. Moreover, we demonstrated that for this system, benzene oxidation proceeded via the Marks-van Krevelen mechanism.