Mechanism of iron doping promoting high temperature deNOx and anti-water vapor and SO2 poisoning of ZrW(Fe)Ox

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• Z 1 W 0.2 F 0.007 was active for NH 3 -SCR of NO at 400–650 °C. • Fe doping improved activity of Z 1 W 0.2 F x for NH 3 -SCR of NO at 350–450 °C. • Fe doping enhanced anti-water vapor interference ability of Z 1 W 0.2 F 0.007 . • H 2 O promoted the Eley-Rideal deNO x reaction at high temperature. • H 2 O promoted deNO x activity and N 2 selectivity of Z 1 W 0.2 F 0.007 at above 450 ℃. Driven by the strategy of reducing pollution and CO 2 , high temperature deNO x catalyst has become a major demand for current gas-fired exhaust purification. A series of Fe-doped ZrWO x complex oxides (Z 1 W 0.2 F x ) were prepared by solution evaporation and co-firing method, and effects of Fe doping on their high-temperature deNO x activity, N 2 selectivity and anti-water vapor and SO 2 poisoning were mainly investigated and the promotion mechanism of Fe doping was analyzed and discussed. Results showed that Fe doping significantly improved NH 3 -SCR of NO over the Z 1 W 0.2 F x within 350–450 °C, mainly due to the redox properties of Fe 2 O 3 itself. Appropriate Fe doping increased specific surface area and enhanced surface acidity of Z 1 W 0.2 F x , the Z 1 W 0.2 F 0.007 possessed the optimal catalytic performance for deNO x , with NO conversion more than 90 % and N 2 selectivity more than 95 % at 400–650 °C. Moreover, compared to the blank sample of Z 1 W 0.2 , Fe doping remarkably enhanced anti-water vapor and SO 2 poisoning of Z 1 W 0.2 F x . Due to the competitive adsorption between H 2 O and NH 3 at low temperature, water vapor has a slight influence on deNO x activity at 400 °C. Interestingly, water vapor notably improved deNO x activity and N 2 selectivity at above 450 °C, because water vapor promoted the formation of hydroxyl groups and thus accelerated the Eley-Rideal deNO x at high temperature. SO 2 had no influence on the deNO x performance of Z 1 W 0.2 F x . Furthermore, both Lewis and Bronsted acid sites coexisted on the surface of Z 1 W 0.2 F x , and the NH 3 -SCR of NO over Z 1 W 0.2 F x at high temperature followed both Langmuir-Hinshelwood and Eley-Rideal reaction mechanisms.