Boosting the catalytic performance of Fe/Zr catalyst by tungsten addition for selective catalytic reduction of NO with ammonia

Doping WO 3 with proper amount could increase the concentration of Fe 3+ and chemisorbed oxygen, and enhance the surface acidity and redox ability. The in-situ DRIFTS spectra demonstrated that only the E-R mechanism was followed in the NH 3 -SCR reaction on Fe/Zr catalyst, while the NH 3 -SCR on Fe/Zr-0.1W catalyst followed both Eley-Rideal and Langmuir-Hinshelwood mechanisms. • WO 3 doped Fe/Zr catalysts were prepared via wet impregnation. • The introduction of WO 3 enhanced the catalytic performance of Fe/Zr catalyst. • WO 3 doping promoted the amount of surface acid sites and the adsorption of NH 3 . • WO 3 doping increased the L-H reaction pathway on the surface of Fe/Zr catalyst. To clarify the effect of WO 3 doping over Fe/Zr catalyst, several Fe/Zr- x W catalysts were prepared via conventional wet impregnation method, and the selective catalytic reduction (SCR) performance was studied. The Fe/Zr-0.1 W catalyst showed the highest catalytic activity and achieved nearly 100 % in a wide operating temperature window of 300–500 °C, and the N 2 selectivity exceeded 90 % over the entire temperature range under a high hour space velocity of 90, 000 h −1 . In addition, Fe/Zr-0.1 W catalyst also exhibited superior resistance to SO 2 compared to Fe/Zr catalyst without WO 3 introduction. Further characterization results indicated that the Fe/Zr-0.1 W catalyst possessed larger BET specific surface area, better dispersion of active component, higher concentration of Fe 3+ and more surface chemisorbed oxygen species, which might be the predominant factors for its superior catalytic performance. More importantly, WO 3 doping improved the redox capacity and surface acidity, thus promoting the redox circle and enhancing the adsorption ability of NH 3 . According to the transient in-situ DRIFTS experiment results, the doping of WO 3 increased the L-H reaction pathway on the surface of Fe/Zr catalyst during the NH 3 -SCR reaction. The present work could provide a new way for developing a high-performance non-vanadium SCR catalyst in practical application.