New insight on optimization of acid promoter over Fe/Zr catalyst for selective catalytic reduction of NOx with NH3. Issue 6 (December 2022)

• Record Type: Journal Article
• Authors: Li, Xiaodi; Ren, Shan; Xing, Xiangdong; Jiang, Yanhua; Chen, Lin; Liu, Lian; Li, Jiangling; Yang, Jian; Liu, Qingcai
• Is Part Of: Journal of environmental chemical engineering. Volume 10:Issue 6(2022)
• Publication Date: 2022-12
• Subjects: Nitrogen oxides -- NH3-SCR -- Acidic promoter -- Fe/Zr catalyst; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2022.108925
• Languages: English
• ISSNs: 2213-2929

Abstract

Abstract: MoO3 and WO3, as acidic promoter, were widely used in the modification of vanadium based and vanadium-free based catalysts, which could significantly ameliorate the catalytic performance of the catalysts. In this work, the effects of MoO3 and WO3 on the selective catalytic reduction (SCR) performance of Fe/Zr catalyst were studied, and the role of acidic promoters was clarified. The results indicated that MoO3 and WO3 could improve the catalytic activity of Fe/Zr catalyst in the entire reaction temperature range. Noteworthy, Fe/Zr-W catalyst exhibited the highest SCR catalytic activity, and the NO x conversion rate achieved nearly 100% at 250 °C. The characterization results suggested that the promoting effect of WO3 on catalytic performance of Fe/Zr catalyst might be due to the improvement of redox property and surface acidity, higher Fe 3+ /(Fe 2+ +Fe 3+ ) ratio and abundant surface chemisorbed oxygen. The in-situ DRIFTS experiments indicated that both E-R and L-H mechanisms were obeyed on Fe/Zr-W catalyst, while only E-R mechanism was obeyed on Fe/Zr and Fe/Zr-Mo catalysts in the NH3 -SCR reaction at 250 °C. This study might provide an alternative development of high-performance vanadium-free catalyst for NO x abatement. Graphical Abstract: ga1 Highlights: Acidic promoter of WO3 or MoO3 enhanced catalytic activity of Fe/Zr catalyst. WO3 doping increased surface acidity, Fe 3+ /(Fe 2+ + Fe 3+ ) ratio and surface adsorbed oxygen of Fe/Zr-W catalyst. MoO3 doping inhibited NO x adsorption but promoted over-oxidation of NH3 on Fe/Zr-Mo catalyst. Mechanism model of acidic promoter doping on Fe/Zr catalyst for NH3 -SCR was proposed.