Efficient degradation of chlorobenzene in a non-thermal plasma catalytic reactor supported on CeO_2/HZSM-5 catalysts

Chlorobenzene removal was investigated in a non-thermal plasma reactor using CeO2/HZSM-5catalysts.The performance of catalysts was evaluated in terms of removal and energy efficiency.The decomposition products of chlorobenzene were analyzed.The results show that CeO2/HZSM-5 exhibited a good catalytic activity,which resulted in enhancements of chlorobenzene removal,energy efficiency,and the formation of lower amounts of by-products.With regards to CO2 selectivity,the presence of catalysts favors the oxidation of by-products,leading to a higher CO2 selectivity.With respect to ozone,which is considered as an unavoidable by-product in air plasma reactors,a noticeable decrease in its concentration was observed in the presence of catalysts.Furthermore,the stability of the catalyst was investigated by analyzing the evolution of conversion in time.The experiment results indicated that CeO2/HZSM-5 catalysts have excellent stability：chlorobenzene conversion only decreased from 78%to 60%after 75 hr,which means that the CeO2/HZSM-5 suffered a slight deactivation.Some organic compounds and chlorinated intermediates were adsorbed or deposited on the catalysts surface as shown by the results of Fourier Transform Infrared（FT-IR） spectroscopy,scanning electron microscope（SEM） and energy dispersive X-ray spectroscopy（EDS） analyses of the catalyst before and after the reaction,revealing the cause of catalyst deactivation.