The influence of chromium substitution on an iron–titanium catalyst used in the selective catalytic reduction of NO

• Published in: Journal of catalysis Vol. 292; pp. 32 - 43
• Main Authors: Karami, Asghar, Salehi, Vajiheh
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.08.2012; Elsevier; Elsevier BV
• Subjects: adsorption; ammonia; analytical methods; Catalysis; Catalysts; Chemistry; Chromium; Colloidal state and disperse state; coprecipitation; Cr substitution; Exact sciences and technology; General and physical chemistry; Iron; Lewis acids; nitric oxide; nitrogen; NOx adsorption; oxygen; porosity; Porous materials; Redox behavior; Selective catalytic reduction; Surface physical chemistry; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Titanium; Cr substitution; Redox behavior; NOx adsorption; Selective catalytic reduction; NO; Acidic site; Adsorption capacity; Mobility; Distortion; Iron; Selectivity; Chemical reduction; Precipitation; Brönsted acid; Substitution; Surface properties; Adsorption structure; Titanium; Oxidation; Lewis acid; Nitrogen oxide; Oxygen; Catalytic reaction; Lewis site; Transition metal; Bronsted site; Ammonia; Heterogeneous catalysis; Adsorption; Chromium; Porosity; Catalyst
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2012.04.007

The selective catalytic reduction (SCR) of NO by NH3 over chromium-substituted Fe titanate catalysts with different amounts of chromium has been studied. The experiments revealed that the amount of chromium in the catalyst is a crucial factor for high activity. Fe0.5Cr0.5TiOx showed the highest activity. A series of Cr-substituted Fe–Ti compounds were prepared by the co-precipitation method and were systematically investigated as catalysts for the selective catalytic reduction (SCR) of NO by NH3. A variety of analytical techniques revealed that the Cr substitution amount affects the N2 selectivity, SCR activity, redox behavior of NH3/NOx, adsorption ability, and structure of catalysts in terms of surface properties, porosity, mobility of lattice oxygen, oxidative ability of Cr species, ratio of Brønsted acid sites and Lewis acid sites, NOx adsorption capacity, and structural disorder and distortion. In a series of FeaCr1−aTiOx (a=1, 0.75, 0.5, 0.2, 0) catalysts, Fe0.5Cr0.5TiOx showed the highest activity because of the optimized interactions of Fe, Cr, and Ti species in this catalyst.