title: DRIFT studies on promotion mechanism of H3PW12O40 in selective catalytic reduction of NO with NH3.
abstract: Heteropoly acids (HPAs) have been effectively utilized in selective catalytic reduction (SCR) of NO to improve the NH3 absorption capacity and alkaline/alkali metal resistance for SCR catalysts. However, despite the promise on super-acidities, their other properties that would work on SCR process are still lack of exploration. In this study, a 12-tungstaphosphoric acid (H3PW12O40, HPW) was selected to modify a well-reported CeO2 catalyst. The resulted CeO2/HPW catalyst was subsequently utilized for SCR of NO with excess NH3, which revealed a significantly promoted performance in SCR reaction. DRIFT analyses showed that the unique NO2 absorption capacity of HPW could prevent the NO2 being further oxidized into nitrate species and the abundant Brønsted acid sites could effectively retain the NH3, avoiding them being over-oxidized at evaluated temperatures. The presence of NO2 was demonstrated able to induce a so called "fast SCR" reaction over the CeO2/HPW catalyst, which effectively facilitated the SCR reaction. Furthermore, we have also constructed a CeO2@HPW catalyst, which showed an enhanced SO2 poisoning resistance in SCR reaction.
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Yuhangtang Road 388, Hangzhou 310058, China.
authors.forename: Xiaole
authors.initials: X
authors.lastname: Weng
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Yuhangtang Road 388, Hangzhou 310058, China.
authors.forename: Xiaoxia
authors.initials: X
authors.lastname: Dai
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Yuhangtang Road 388, Hangzhou 310058, China.
authors.forename: Qingshan
authors.initials: Q
authors.lastname: Zeng
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Yuhangtang Road 388, Hangzhou 310058, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Yuhangtang Road 388, Hangzhou 310058, China; Zhejiang Provincial Engineering Research Center of Industrial Boiler & Furnace Flue Gas Pollution Control, Yuhangtang Road 388, Hangzhou 310058, China. Electronic address: zbwu@zju.edu.cn.
authors.forename: Zhongbiao
authors.initials: Z
authors.lastname: Wu
keywords: CeO(2); DRIFT; HPW; Heteropoly acid; NO(x); SCR