Study on the structure-activity relationship of Fe-Mn oxide catalysts for chlorobenzene catalytic combustion

The catalytic elimination of chloroaromatics is the frontier of catalytic oxidation of volatile organic compounds (VOCs), and the screening of efficient catalysts (low cost, high activity, durability and selectivity) remains challenging. In this work, a series of porous Fe-Mn oxides were synthesized via a simple template-free oxalate route. The Fe/Mn ratio influences the chlorobenzene (CB) combustion activity of the catalysts, among which Fe1Mn1 catalyst performs excellent catalytic activity with a T-50 and T-90 of 160 and 197 degrees C (600 ppm CB/dry air, GHSV = 20000 h(-1)), high selectivity for less toxic products (HCl and CO2), scarce formation of chlorinated byproduct (DCB) and relatively good durability. Characterization results show that the synergistic effect between acid properties, redox properties and the oxidation state of manganese are critical for promoting the catalytic performance of CB. The strong interaction between Fe and Mn enhances the surface Mn4+ content and redox property of Fe-Mn oxide, which further improve the low temperature activity and selectivity. Besides, more and stronger medium acid sites are present on the surface of Fe-Mn oxide, which facilitate the dechlorination reaction and C-C band cleavage. Under the synergetic effects of above-mentioned factors, the activity of Fe1Mn1 is remarkably enhanced and would be promising for potential industrial application.