Mechanism for Nb promoting NO selective catalytic reduction with NH3 over FeCeOx catalysts
AN Dongqi1, YANG Yuyao1, CAI Yandi2, ZOU Weixin2*, SUN Jingfang3*, DONG Lin1, 2, 3
(1 Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, Jiangsu, China;2 School of the Environment, Nanjing University,Nanjing 210093, Jiangsu, China;3 Jiangsu Key Laboratory of Vehicle Emissions Control, Center of Modern Analysis, Nanjing University,Nanjing 210093, Jiangsu, China)
Abstract:
The selective catalytic reduction with NH3(NH3-SCR) is one of the most prominent technologies to eliminate the important pollutants of nitrogen oxides (NOx) in the atmosphere. A series of Nb promoted NbaFe1-aCeOx(a=0, 0.1, 0.2, 0.4) catalysts were prepared by co-precipitation method for NH3-SCR of NO. The physical and chemical properties of the catalysts were characterized by BET, XRD, XRF, NH3-TPD, H2-TPR and in situ DRIFTS. Results showed that the introduction of Nb significantly improved the low- and mid-temperature denitration performance of the FeCeOxcatalysts. The Nb0.1Fe0.9CeOxcatalyst achieved more than 80% of NOxconversion rate between 175 ℃ and 350 ℃, exhibiting the best NH3-SCR activity among the prepared NbaFe1-aCeOxcatalysts. The SCR reaction on the Nb0.1Fe0.9CeOxcatalyst followed the Eley-Rideal reaction mechanism,and its excellent SCR performance could be ascribed to the strong interaction between Nb, Fe and Ce due to the introduction of appropriate amount of Nb, which decreased the crystallinity, increased the specific surface area and gave rise to the redox property of the catalyst.The adsorption and activation of NH3were also encouraged by the enhanced surface acidity.
KeyWords:
NH3-SCR; low-temperature denitration; Nb species modification; FeCeOxcatalysts
