Effect of La/Ce modification over Cu based Y zeolite catalysts on high temperature selectivity for selective catalytic reduction with ammonia. (15th August 2022)

• Record Type: Journal Article
• Authors: Xie, Junlin; Jin, Qiqi; Fang, De; Ye, Yanli; Hou, Sensheng; Wang, Xiaohui; He, Feng
• Is Part Of: Journal of cleaner production. Volume 362(2022)
• Publication Date: 2022-08-15
• Subjects: Selectivity catalytic reduction -- Denitrification -- CuY -- La/Ce; Factory and trade waste -- Management -- Periodicals; Manufactures -- Environmental aspects -- Periodicals; Déchets industriels -- Gestion -- Périodiques; Usines -- Aspect de l'environnement -- Périodiques; 628.5
• DOI: 10.1016/j.jclepro.2022.132255
• Languages: English
• ISSNs: 0959-6526

Abstract

Abstract: CuY zeolite catalyst is considered to be one of most promising catalysts for selective catalytic reduction with ammonia (NH3 -SCR), but its main byproduct is the greenhouse gas N2 O. To increase N2 selectivity, the modification mode and promotion mechanism of La/Ce doping with two-step ion exchange method were investigated. Impressively, CuLaY achieved above 90% efficiency from 140 °C to 380 °C and less N2 O production especially at the temperature above 250 °C. The characterization results showed La/Ce doping increased the content of surface Cu 2+ species and improved the oxidation ability of Cu ions in catalysts. However, the formation of La/Ce oxides on the zeolite surface had an adverse impact on the SCR activity, while Ce oxides were more easily formed than La oxides. In addition, more abundant adsorbed NOx species and stronger NH3 adsorption on the surfaces enhanced L-H mechanism for CuLaY with high N2 selectivity above 250 °C. Graphical abstract: The interaction between La or Ce species with Cu species enhanced low N2 O production especially at high temperature for more abundant nitrate adsorbed species and stronger NH3 species on the surface. Image 1 Highlights: La doping improved both of catalytic activity and N2 selectivity for CuY. La doping increased the surface Cu 2+ species content and formed La–O–Cu species. La doping enhanced L-H reaction pathway evidenced by in situ DRIFTS at different temperature.