Hierarchical Ru-Ce/H-ZSM-5 catalysts for the catalytic oxidation of chlorobenzene: Structure-activity relationship and chlorine poisoning resistance

A series of hierarchical Ru-Ce/H-ZSM-5 were designed and synthesized using the sol-gel method, and they were applied as catalysts for the catalytic combustion of chlorobenzene. The pore diameter of the catalyst was adjusted using an amount of sodium alginate (SA). Among all of the catalysts synthesized, the 0.8 wt.%Ru-10 wt.%Ce/H-ZSM-5 catalyst with a crystallization recipe of 1SiO2: 0.02Al2O3: 0.15TPAOH: 0.04SA: 40H2O (named RCZA-0.04) exhibited the optimal catalytic activity, with the 90% conversion of chlorobenzene at 247 °C. In addition, the RCZA-0.04 catalyst maintained superb stability during a long-term reaction at 325 °C. The results of characterizations demonstrated that RCZA-0.04 possessed the largest mesoporous volume, which reduced the diffusion resistance of chlorobenzene and increased the dispersion of the active components, thereby enhancing the catalytic activities. Moreover, the RCZA-0.04 catalyst possessed a low Brønsted/Lewis ratio, which was conducive to the adsorption of chlorobenzene and the cleavage of the CCl bond.