催化作用
X射线光电子能谱
氧化剂
漫反射红外傅里叶变换
选择性
扫描电子显微镜
选择性催化还原
材料科学
催化氧化
粉末衍射
化学
分析化学(期刊)
无机化学
化学工程
结晶学
光催化
生物化学
工程类
色谱法
复合材料
有机化学
作者
Anqi Dong,Zhi Yang,Weichao Wang
出处
期刊:ACS omega
[American Chemical Society]
日期:2022-03-04
卷期号:7 (10): 8633-8639
被引量:7
标识
DOI:10.1021/acsomega.1c06648
摘要
Low-temperature selective catalytic oxidation (SCO) is crucial for removing the NH3 slip from the upstream of NH3-selective catalytic reduction (NH3-SCR). Herein, combining zeolite Cu-SAPO34 and the active oxidant mullite SmMn2O5, we developed mixed-phase catalysts SmMn2O5/Cu-SAPO34 by grinding powder mixtures to achieve a low-temperature activity and a reasonable N2 selectivity. The physicochemical properties of the catalysts were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) measurement, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The evaluation of NH3 oxidation activity showed that for 30 wt % SmMn2O5/Cu-SAPO34, 90% NH3 conversion was at a temperature of 215 °C in the presence of 500 ppm NH3 and 21% O2 balanced with N2. The in situ DRIFTS spectra reveal the internal SCR mechanism (i-SCR), i.e., NH3 oxidizing to NO x on mullite and NO x subsequently to proceed with SCR reactions, leading to higher conversion and selectivity over the mixed catalysts. This work provides a strategy to design the compound catalyst to achieve low-temperature NH3 oxidation via synergistic utilization of the advantages of each individual catalyst.
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