Investigation of the common intermediates over Fe-ZSM-5 in NH_3-SCR reaction at low temperature by in situ DRIFTS
Investigation of the common intermediates over Fe-ZSM-5 in NH_3-SCR reaction at low temperature by in situ DRIFTS
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原位DRIFTS研究低温NH_3-SCR反应中Fe-ZSM-5常见中间体
DOI：
10.1016/j.jes.2020.02.029
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发表时间：
2020
影响因子：
--
通讯作者：
He Hong
中科院分区：
文献类型：
--
作者：
Shi Xiaoyan;Wang Yingjie;Shan Yulong;Yu Yunbo;He Hong
采用原位漫反射红外傅里叶变换光谱(DRIFTS)研究了低温(140 ℃)下NO和NO_2与预吸附NH_3在Fe-ZSM-5催化剂(1.27 wt.% Fe, SiO_2 /Al 2 O_3 = 25)上反应形成的表面物种。通过使用NH_3饱和的Fe-ZSM-5的背景光谱，我们清楚地观察到NO_2或NO + O_2与预吸附的NH_3反应产生常见中间体的形成。这有力地证明了NO氧化形成表面硝酸盐和亚硝酸盐是标准低温SCR的关键步骤。此外，结果表明，在低温SCR反应中，吸附在Bronsted酸位上的NH_4~+离子的活性低于吸附在与Fe物种相关的Lewis酸位上的NH_3离子。
The surface species formed in the reaction of NO and NO_2 with pre-adsorbed NH_3 over a Fe-ZSM-5 catalyst (1.27 wt.% Fe, SiO_2 /Al 2 O_3 = 25) at low temperature (140 °C) were studied by in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Through using a background spectrum of NH_3-saturated Fe-ZSM-5, we clearly observed the formation of common intermediates resulting from the reaction of NO_2 or NO + O_2 with pre-adsorbed NH_3 . This presents strong evidence that the oxidation of NO to form surface nitrates and nitrites is the key step for standard SCR at low temperature. In addition, the results suggest that in the SCR reaction at low temperature, the NH_4~+ ions absorbed on Bronsted acid sites are less active than NH_3 adsorbed on Lewis acid sites related to Fe species.