Structures and catalytic performances of Me/SAPO-34 (Me = Mn, Ni, Co) catalysts for low-tem perature SCR of NOx by ammonia


Xiaodong Wu , Xuesong Liu , Zhiming Sui , Hongfeng Chen , Yong Chen , Haigang Liu , Peng Jiang , Zhongyun Shen , Wensheng Linghu

DOI:10.1016/j.jes.2020.11.018

Received July 26, 2020,Revised , Accepted November 16, 2020, Available online December 18, 2020

Volume 33,2021,Pages 137-149

Me/SAPO-34 (Me = Mn, Ni, Co) series of catalysts were prepared by a wetness impregnation method and investigated for the selective catalytic reduction of nitrogen oxides with ammonia (NH3-SCR). Among them, Mn/SAPO-34 catalyst was found as the most promising candidate based on its superior low-temperature activity. The catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy images (TEM), nuclear magnetic resonance (NMR), X-ray photoelectron spectroscopy (XPS), temperature programmed reduction and desorption (TPR and TPD), and diffuse reflectance infrared Fourier transformed spectroscopy (DRIFTS) of NH3/NOx adsorption. Mn/SAPO-34 is obviously different from Ni/SAPO-34 and Co/SAPO-34 in the active species state and distribution. Surface MnOx species which play an essential role in NO oxidation and NO2 adsorption, act as better active sites than nickel and cobalt mostly in the form of the aluminates and silicates.

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