Synthetic structure effect of CuO/NaZSM-5 on the catalytic oxidation of chlorinated aromatic hydrocarbon

Abstract

Petrochemical, tobacco, and pharmaceutical processing industries extensively use chlorinated volatile organic compounds (CVOCs) as solvents and lubricants, which cause significant environmental hazards. Zeolite is a highly efficient catalytic material for low-temperature degradation of CVOCs, with strong practical applications in industry. In this study, we used chlorobenzene (CB) as a model pollutant to introduce two innovative modified zeolites: a hollow zeolite-supported CuO catalyst (CuO/Z–HO) and an in situ-grown zeolite catalyst on the surface of the CuO nanosheet (CuO/Z–SC). The results indicate that the synthesized zeolite catalyst, with its unique structural characteristics, enhances CB degradation performance and resistance to poisoning compared to a conventional commercial zeolite-supported CuO catalyst (CuO/Z–WI). Specifically, for the CuO/Z–SC catalyst, the CuO nanosheet enhances the exposure of surface reactive oxygen species to improve C–H oxidation performance, achieving 90% CB removal rate and CO₂ selectivity at temperatures of 340 °C and 390 °C, respectively. Additionally, in situ grown crystallization of NaZSM-5 over the CuO nanosheet selectively adsorbs C–Cl through Brønsted acid and then transfers C–H compounds to the Cu–O oxidation center, resulting in chlorination primarily targeting NaZSM-5, which thus protects the Cu site. This study offers valuable insights into enhancing the oxidation performance and chlorine poisoning resistance of zeolite catalysts for the elimination of CVOCs through structural control.