Dataset Information

Ce regulated surface properties of Mn/SAPO-34 for improved NH₃-SCR at low temperature.

ABSTRACT: Ce modified MnO _x /SAPO-34 was prepared and investigated for low-temperature selective catalytic reduction of NO _x with ammonia (NH₃-SCR). The 0.3Ce-Mn/SAPO-34 catalyst had nearly 95% NO conversion at 200-350 °C at a space velocity of 10 000 h^-1. Microporous SAPO-34 as the support provided the catalyst with increased hydrothermal stability. XPS and H₂-TPR results proved that the Mn⁴⁺ and O_α content increased after incorporation of Ce, this promoted the conversion of NO at low temperature via a 'fast SCR' route. NH₃-TPD measurements combined oxidation experiments of NO, NH₃ indicated the reduction of both the surface acidity and the amount of acid sites, which effectively decreased the NH₃ oxditaion to NO or N₂O at elevated temperature and promoted the catalytic selectivity for nitrogen. A redox cycle between manganese oxide and Ce was assumed for the active oxygen transfer and facilitated the catalyst durability.

SUBMITTER: Chen Q

PROVIDER: S-EPMC9057469 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Ce regulated surface properties of Mn/SAPO-34 for improved NH3-SCR at low temperature.

Chen Qizhi Q Yang Yong Y Luo Hang H Liu Zuohua Z Tong Zhangfa Z Tao Changyuan C Du Jun J

RSC advances 20201104 66

Ce modified MnO x /SAPO-34 was prepared and investigated for low-temperature selective catalytic reduction of NO x with ammonia (NH3-SCR). The 0.3Ce-Mn/SAPO-34 catalyst had nearly 95% NO conversion at 200-350 °C at a space velocity of 10 000 h-1. Microporous SAPO-34 as the support provided the catalyst with increased hydrothermal stability. XPS and H2-TPR results proved that the Mn4+ and Oα content increas ...[more]

PMID: 35520869

Similar Datasets

Project description:The group has shown that Baiyun Ebo rare earth concentrate has excellent performance in NH3-SCR denitrification when used as a carrier, where rare earth elements are mainly present in cerium fluorocarbon ore (CeCO3F) and monazite (CePO4) mineral phases. In this paper, a new low-temperature NH3-SCR catalyst of Mn-Fe/CeCO3F-monazite was prepared by an impregnation method, using synthetic CeCO3F and purified monazite as carriers. By exploring its denitrification performance and mechanistic analysis, it provides theoretical guidance for the use of rare earth concentrates as low-temperature NH3-SCR catalysts. Our previous studies have determined the optimum loading of Fe, so this paper needs to be investigated for the optimum doping ratio of the active substance Mn. The results of the activity tests, XRD and BET have determined that the best denitrification rate and catalytic performance was achieved at a ratio of Mn : Ce of 1 : 5. The denitrification activity of the different catalysts was investigated by loading Fe, Mn and Fe and Mn together. The results obtained by means of experimental analyses such as XRD, SEM, BET and activity tests showed that the composite catalyst loaded with Fe and Mn at the same time, had the highest activity and its denitrification rate could reach 94.8% at 250 °C. This is mainly attributed to the fact that the interaction of Fe, Mn can promote the dispersion of each other on the carrier surface, which greatly improves the specific surface area of the catalyst. The introduction of Fe and Mn increases the acidic sites and the amount of acid on the catalyst surface, which results in the formation of a large number of oxygen vacancies and the presence of more oxygen species on the catalyst surface, which facilitate the migration of oxygen. The new catalyst was investigated by Fourier transform infrared (FTIR) spectroscopy to characterise the adsorption and transformation behaviour of the reactive species on the surface of the catalyst, and to investigate the reaction mechanism. The results showed that the entire reaction process followed the L-H mechanism, with the gaseous NO adsorption and activation on the catalyst surface generating bidentate nitrate, bridging nitrate species and NH3/NH4 + species as the main intermediate species involved in the reaction, both of which underwent redox reactions on the catalyst surface to produce N2 and H2O. The above results indicated that the CeCO3F-monazite carrier has excellent performance, and provided a theoretical basis for the high-value utilization of rare earth concentrates.

Dataset Information

Ce regulated surface properties of Mn/SAPO-34 for improved NH₃-SCR at low temperature.

Publications

Ce regulated surface properties of Mn/SAPO-34 for improved NH<sub>3</sub>-SCR at low temperature.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets