Effect of samarium on the N_(2) selectivity of Sm_(x)Mn_(0.3-x)Ti catalysts during selective catalytic reduction of NO_(x) with NH_(3)  

作　　者：Shengyang Zhang Bolin Zhang Boyu Wu Bo Liu Shengen Zhang 

机构地区：[1]Institute for Advanced Materials and Technology,University of Science and Technology Beijing,Beijing 100083,China [2]Shunde Innovation School,University of Science and Technology Beijing,Foshan 528399,China

出　　处：《International Journal of Minerals,Metallurgy and Materials》2023年第4期642-652,共11页矿物冶金与材料学报（英文版）

基　　金：sponsored by the National Key R&D Program of China(Nos.2021YFC1910504,2019YFC 1907101,and 2019YFC1907103);the Key R&D Program of Ningxia Hui Autonomous Region,China(Nos.2020BCE01001 and 2021BEG01003);the National Natural Science Foundation of China(Nos.U2002212,51672024,52102058,and 52204414);the Xijiang Innovation and Entrepreneurship Team(No.2017A0109004);the Fundamental Research Funds for the Central Universities(Nos.FRF-TP20-097A1Z and FRF-TP-20-031A1);the Foshan Science and Technology Innovation Special Foundation(No.BK22BE001)。

摘　　要：This work aims to study the improvement effect of Sm on Mn-based catalysts for selective catalytic reduction (SCR) of NO with NH3.A series of Sm_(x)Mn_(0.3-x)-xTi catalysts (x=0,0.1,0.15,0.2,and 0.3) were prepared by co-precipitation.Activity tests indicated that the Sm_(0.15)Mn_(0.15)Ti catalyst showed superior performances,with a NO conversion of 100%and N_(2)selectivity above 87%at 180–300℃.The characterizations showed that Sm doping suppressed the crystallization of TiO_(2)and Mn2O3phases and increased the specific surface area and acidity.In particular,the surface area increased from 152.2 m^(2)·g^(-1)for Mn0.3Ti to 241.7 m^(2)·g^(-1)for Sm_(0.15)Mn_(0.15)Ti.These effects contributed to the high catalytic activity.The X-ray photoelectron spectroscopy (XPS) results indicated that the relative atomic ratios of Sm^(3+)/Sm and Oβ/O of Sm_(0.15)Mn_(0.15)Ti were 76.77at%and 44.11at%,respectively.The presence of Sm contributed to an increase in surface-absorbed oxygen (Oβ) and a decrease in Mn^(4+)surface concentration,which improved the catalytic activity.In the results of hydrogen temperature-programmed reduction(H_(2)-TPR),the presence of Sm induced a higher reduction temperature and lower H_(2)consumption (0.3 mmol·g^(-1)) for the Sm_(0.15)Mn_(0.15)Ti catalyst compared to the Mn0.3Ti catalyst.The decrease in Mn^(4+)weakened the redox property of the catalysts and increased the N_(2)selectivity by suppressing N_(2)O formation from NH3oxidation and the nonselective catalytic reduction reaction.The in situ diffuse reflectance infrared Fourier transform spectra (DRIFTs) revealed that NH3-SCR of NO over the Sm_(0.15)Mn_(0.15)Ti catalyst mainly followed the Eley–Rideal mechanism.Sm doping increased surface-absorbed oxygen and weakened the redox property to improve the NO conversion and N_(2)selectivity of the Sm_(0.15)Mn_(0.15)Ti catalyst.

关 键 词：manganese oxides nitric oxide nitrous oxide SAMARIUM selective catalytic reduction nitrogen selectivity 

分 类 号：O643.36[理学—物理化学]