Sb-loaded MnOx/TiO₂/CNTs catalysts for selective catalytic reduction of NOx: insight to the SO₂ and H₂O tolerance

Purpose This paper aims to synthesize and test Mn-Sb/TiO 2 -CNT catalysts with different Sb/Mn molar ratios to be used in NH 3 -SCR reaction. Design/methodology/approach A series of Sb-loaded carbon nanotubes (CNTs)-based Mn/TiO 2 catalysts were prepared by the incipient wetness co-impregnation method and tested for the selective catalytic reduction (SCR) of NOx with NH 3 . Findings The Sb-loaded Mn/TiO 2 -CNTs catalyst outperformed other catalysts and presented the highest activity in the temperature regime of 100–400°C. The catalyst loaded with Sb also showed good SO 2 and H 2 O resistance and exhibited better thermal stability. A stepwise study of SO 2 addition evidenced that Mn-Sb/TiO 2 -CNTs catalyst exhibited better SO 2 resistance than the base catalyst Mn/TiO 2 , where the Sb doping greatly inhibited the sulphating of active phase of the catalyst. Originality/value In Sb-loaded catalysts, the formed SOx species fused with SbOx instead of MnOx. This favoured interaction of SO 2 with SbOx successfully prevents the MnOx from being sulphated by SO 2 which substantially improves the SO 2 tolerance of Sb-loaded catalysts.