Insights into the Electronic Structure Effect of SnMnOx Nanorod Catalysts for Low-Temperature Catalytic Combustion of o-Dichlorobenzene

For the catalytic combustion reaction of chlorinated volatile organic compounds (CVOCs), the redox properties and acid sites of the catalyst surface are key factors in determining the activity, selectivity, and chlorine-resistance stability. Herein, a series of SnMnOx catalysts for the catalytic combustion of CVOCs were prepared by the changing of Sn-doping way to regulate the electron valance state of Mn element, including reflux (R-SnMnOx), co-precipitation (C-SnMnOx) and impregnation (I-SnMnOx). It was discovered that the R-SnMnOx catalyst had better activity and chlorine resistance than the R-MnOx, C-SnMnOx and I-SnMnOx catalyst, and we discovered that the doping ways of Sn in MnOx catalyst could regulate greatly the surface acidity, active oxygen species, the chemical state of Mnn+ species, and redox ability. Especially, the R-SnMnOx catalysts exhibit excellent water resistance, and the reasons were related to the strong interaction of Snn+ and Mnn+, which could promote obviously the dispersion of active Mn species, form a large number of acid sites, provide the abundant lattice oxygen species, and own the excellent redox ability, which accelerate the rate of charge transfer between Snn+ and Mnn+ (Sn4++Mn2+& RARR;Sn2++Mn4+) to produce the abundant active species and accelerate the rapid conversion of benzene and intermediates conversion.

Automated summary

This study examines the effects of the redox properties and acid sites on the catalyst surface on the activity, selectivity, and chlorine-resistance stability of catalysts for the catalytic combustion of chlorinated volatile organic compounds (CVOCs). SnMnOx catalysts were prepared using different Sn-doping methods to modulate the electron valence state of Mn. The R-SnMnOx catalyst exhibited superior activity and chlorine resistance compared to the R-MnOx, C-SnMnOx, and I-SnMnOx catalysts. The doping of Sn in the MnOx catalyst greatly affected the surface acidity, active oxygen species, the chemical state of Mnn+ species, and redox ability. The R-SnMnOx catalysts showed excellent water resistance, which can be attributed to the strong interaction between Snn+ and Mnn+ that promotes the dispersion of active Mn species, formation of acid sites, availability of lattice oxygen species, and enhanced redox ability, resulting in faster conversion of benzene and intermediates.