Mn-based catalysts for ammonia selective catalytic reduction of NO_x exhibit good low-temperature activity but poor sulfur resistance. Doping with Sb resulted in a perforated porousness layered foam micromorphology, which promoted molecular mass transfer of the reaction gas and diffusion of the reactants/products, enhanced the catalytic activity, and increased the resistance to sulfur poisoning.

Abstract

Manganese-antimony composite oxide catalysts were prepared for use in low-temperature selective catalytic reduction of flue gas, by adopting the strategy of passivation to regulate the valence state of the active component and control catalytic activity. Activity evaluation results found that MnSb_0.36O_y delivered 80 % NO conversion in the presence of SO₂ at 200 °C, and nearly 90 % conversion at 250 °C. Doping with Sb changed the surface micromorphology, resulting in a perforated porousness layered foam with a porous structure of tens of nanometers, which was conducive to molecular mass transfer of the reaction gas. Doping with Sb regulated the valence state of the active MnO_x component, which diminished catalytic oxidation of SO₂, thus promoting catalyst stability and limiting the toxic effect of SO₂.