Promoting H2O/SO2 resistance of Ce-Mn/TiO2 nanostructures by Sb5+/Sb3+ addition for Selective catalytic reduction of NO with NH3

A series of xSb-4Ce-10Mn/TiO2 (x = 0, 2, 3, 4, 5, 6) catalysts were prepared by a reverse co-precipitation method. The catalysts were characterized by XRD, TEM, Raman, XPS, etc. The effect of the Sb5+/Sb3+ loading on the NO conversion and H2O/SO2 resistance was studied. The xSb-4Ce-10Mn/TiO2 displayed the highest low -temperature catalytic activity, best N-2 selectivity and best H2O/SO2 resistance at x = 4. The Sb5+/Sb3+ addition slightly decreased the catalytic activity, but helped to improve the H2O/SO2 resistance. Meanwhile, the Sb5+/ Sb3+ addition decreased the Mn4+ and Ti4+ content, but increased the Ce3+ and surface adsorbed oxygen content of the catalyst. In the presence of SO2, the Bronsted acid sites of the 4Sb-4Ce-10Mn/TiO2 increased. Results showed the Sb5+/Sb3+ addition enlarged the surface area, made (NH4)(2)SO4 easy to decompose and inhibited the MnSO4 formation, which contributed to the improvement of the H2O/SO2 resistance. Transient in situ DRIFT spectra showed the reaction of the NH3-SCR over the catalysts belongs to the Langmuir-Hinshelwood (L-H) mechanism.

Automated summary

A series of xSb-4Ce-10Mn/TiO2 catalysts with different Sb5+/Sb3+ loadings were prepared and their performances were investigated. The catalyst with a loading of 4 showed the best catalytic activity, selectivity, and resistance. The addition of Sb5+/Sb3+ slightly decreased the activity but improved the resistance, and also altered the chemical composition of the catalyst.