DRIFT studies on promotion mechanism of H3PW12O40 in selective catalytic reduction of NO with NH3

Xiaole Weng; Xiaoxia Dai; Qingshan Zeng; Yue Liu; Zhongbiao Wu

doi:10.1016/j.jcis.2015.09.004

DRIFT studies on promotion mechanism of H3PW12O40 in selective catalytic reduction of NO with NH3

J Colloid Interface Sci. 2016 Jan 1:461:9-14. doi: 10.1016/j.jcis.2015.09.004. Epub 2015 Sep 5.

Authors

Xiaole Weng¹, Xiaoxia Dai¹, Qingshan Zeng¹, Yue Liu¹, Zhongbiao Wu²

Affiliations

¹ Department of Environmental Engineering, Zhejiang University, Yuhangtang Road 388, Hangzhou 310058, China.
² 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.

PMID: 26397902
DOI: 10.1016/j.jcis.2015.09.004

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.

Keywords: CeO(2); DRIFT; HPW; Heteropoly acid; NO(x); SCR.