Sol-gel one-pot synthesis of efficient and environmentally friendly iron-based catalysts for NH3-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 NOx by ammonia (NH3-SCR). Among all the catalysts, Fe0.2W0.2Ti(U0.03, urea-modification) catalyst exhibited more than 95% NOx conversion in range of 240–420 °C, and excellent performance of resistance to SO2 and H2O was observed with a slight decline of NOx conversion to 92%. The characterization results revealed that urea-modified catalyst possessed low crystallinity of TiO2 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 m2/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 FeWO4 solid solution.