Sol-Gel One-Pot Synthesis of Efficient and Environmentally Friendly Iron-Based Catalysts for NH 3 -SCR

Abstract In current study, various pore-forming agents were employed for the synthesis of Fe-W-Ti catalysts via sol-gel one-pot approach, and the catalytic performance was investigated for selective catalytic reduction of NO x by ammonia (NH 3 -SCR). Among all the catalysts, Fe 0.2 W 0.2 Ti(U 0.03 , urea-modification) catalyst exhibited more than 95% NO x conversion in range of 240–420 °C, and excellent performance of resistance to SO 2 and H 2 O was observed with a slight decline of NO x conversion to 92%. The characterization results revealed that urea-modified catalyst possessed low crystallinity of TiO 2 with particle size of 3.8 nm and the dispersion of Fe-W species was increased significantly, which could be ascribed to the high specific surface area (144.92 m 2 /g) and superior porous structure. The sufficient strong acid, the remarkable reducibility and the increase in the ratio of divalent iron & adsorbed oxygen may be responsible for the excellent catalytic activity. Moreover, a dramatic drop in the specific surface area and surface acidity of the hydrothermal aged catalyst was observed, and the active species also became agglomerated with FeWO 4 solid solution.