Simultaneous removal NO and toluene over the Sb enhanced MnOx catalysts

Abstract

xSb-Mn (Sb enhanced MnOx) catalysts with different Sb contents were synthesized by co-precipitation method for the simultaneous removal of NO and toluene. Among them, 5 %Sb-Mn catalyst showed superior NO and toluene conversions, and the NO conversion could reach 90 % in 200–350 °C, toluene conversion could reach 100 % in 200–400 °C. The effects of Sb on MnOx catalyst were explored by XRD, N2 adsorption–desorption, SEM, XPS, which suggested that the appropriate Sb doping could improve the surface area of catalyst and increase the dispersity of active component on catalyst. Moreover, Sb could enhance the surface acidity, redox ability, and chemically adsorbed oxygen content over catalyst, enhancing the catalytic performance. Meanwhile, the Sb significantly improved the SO2 and H2O durability of catalyst, which duo to Sb species inhibiting the oxidation of SO2 by Mn, enhancing the SO2 durability of catalyst. Moreover, the reaction mechanism of 5 %Sb-Mn for simultaneous removal of NO and toluene was analyzed by in-situ DRIFTS. Furthermore, the effect of NH3-SCR process on toluene oxidation was investigated. Those results showed that MnOx and 5 %Sb-Mn catalysts follow the E-R mechanism. Besides, NH3 would react with active oxygen species before toluene, which inhibit further oxidation of toluene intermediates. Notably, the Sb species contributed to reducing the restrain of NH3 on toluene oxidation process.