Low-temperature selective catalytic reduction of NO with NH3 over Mn–Ce–Ox/TiO2: a comparison between catalyst preparation methods

• Published in: Journal of sol-gel science and technology 2020-08, Vol.95 (2), p.332-343
• Main Authors: Chao, Mengxi, Mao, Dongsen, Li, Gehua, Li, Gang, Yu, Jun, Guo, Xiaoming
• Format: Article
• Language: English
• Subjects: Adsorption; Ammonia; Catalysts; Ceramics; Chemical reduction; Chemistry and Materials Science; Citric acid; Composites; Coprecipitation; Fourier transforms; Glass; Inorganic Chemistry; Low temperature; Low temperature resistance; Materials Science; Mixed oxides; Nanotechnology; Natural Materials; Nitrogen oxides; Optical and Electronic Materials; Original Paper: Sol–gel and hybrid materials for catalytic; Oxygen; photoelectrochemical and sensor applications; Photoelectrons; Poisoning; Selective catalytic reduction; Sol-gel processes; Spectrum analysis; Surface chemistry; Temperature; Titanium dioxide; X ray photoelectron spectroscopy
• ISSN: 0928-0707; 1573-4846
• DOI: 10.1007/s10971-020-05268-1

Three Mn–Ce–O x /TiO 2 mixed oxides (MCT) were prepared by sol–gel (SG), citric acid complexing (CA), and co-precipitation (CP) methods and used as catalysts for selective catalytic reduction of NO with NH 3 (NH 3 -SCR) at low temperatures (75–200 °C). The physicochemical properties of the prepared catalysts were investigated by N 2 adsorption, X-ray diffraction (XRD), temperature-programmed reduction by H 2 (H 2 -TPR), adsorption of NH 3 and NO followed by temperature-programmed desorption (NH 3 /NO-TPD), X-ray photoelectron spectroscopy (XPS), and in situ diffuse-reflectance infrared Fourier transform (DRIFT) spectroscopy. The results show that both the low-temperature de-NO x activity and the resistance to SO 2 poisoning of the Mn–Ce–O x /TiO 2 catalyst decrease in the order of MCT-CP > MCT-SG > MCT-CA. These disparities can be mainly attributed to the difference in specific surface area, fractions of Mn 4+ (Mn 4+ /(Mn 2+ +Mn 3+ +Mn 4+ )) and surface adsorbed oxygen (surface adsorbed oxygen/(surface adsorbed oxygen + lattice oxygen)) species, and the adsorption capacity for NH 3 and NO of the different catalysts. The effect of preparation methods (sol–gel, citric acid complexing, and co-precipitation) on the performance of Mn–Ce–O x /TiO 2 catalyst was investigated. The catalyst prepared by co-precipitation exhibits higher low-temperature activity and better SO 2 resistance than the counterparts prepared by the other two methods. Highlights Mn–Ce–O x /TiO 2 catalysts were prepared by sol–gel, citric acid complexing, and co-precipitation. The catalyst prepared by co-precipitation exhibits the highest activity for NH 3 -SCR of NO. The catalyst prepared by co-precipitation exhibits the best tolerance to SO 2 poisoning.