Effect of Cu loading content on the catalytic performance of Cu-USY catalysts for selective catalytic reduction of NO with NH_(3)  

作　　者：Jie Wan Haipeng Yang Yijun Shi Yanjun Liu Jin Zhang Jun Zhang Gongde Wu Renxian Zhou 

机构地区：[1]Energy Research Institute,Nanjing Institute of Technology,Nanjing 211167,China [2]Institute of Catalysis,Zhejiang University,Hangzhou 310028,China

出　　处：《Journal of Environmental Sciences》2023年第4期445-458,共14页环境科学学报（英文版）

基　　金：supported by the Key Program of Science Technology Department of Zhejiang Province (No.2018C03037);the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (No.20KJB610005);the Natural Science Foundation of Jiangsu Province (Nos.BK20201037,BK20190705);Key Research and Development Program of Anhui Province (No.202104g01020006);the Scientific Research Fund of Nanjing Institute of Technology (Nos.YKJ2019111 and YKJ2019110)。

摘　　要：Series of Cu-USY zeolite catalyst with different Cu loading content were synthesized through simple impregnation method.The obtained catalysts were subjected to selective catalytic reduction of NOxwith NH_(3)(NH_(3)-SCR) performance evaluation,structural/chemical characterizations such as X-ray diffraction (XRD),N2adsorption/desorption,H_(2)temperature-programmed reduction (H_(2)-TPR),NH_(3)temperature-programmed desorption (NH_(3)-TPD) as well as detailed in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) experiments including CO adsorption,NH_(3)adsorption and NO+O_(2)in situ reactions.Results show that Cu-USY with proper Cu loading (in this work 5Cu-USY with5 wt.%Cu) could be promising candidates with highly efficient NH_(3)-SCR catalytic performance,relatively low byproduct formation and excellent hydrothermal stability,although its SO_(2)poisoning tolerability needs alleviation.Further characterizations reveal that such catalytic advantages can be attributed to both active cu species and surface acid centers evolution modulated by Cu loading.On one hand,Cu species in the super cages of zeolites increases with higher Cu content and being more conducive for NH_(3)-SCR reactivity.On the other hand,higher Cu loading leads to depletion of Br?nsted acid centers and simultaneous formation of abundant Lewis acid centers,which facilitates NH_(4)NO_(3)reduction via NH_(3)adsorbed on Lewis acid centers,thus improving SCR reactivity.However,Cu over-introduction leads to formation of surface highly dispersed CuOx,causing unfavorable NH_(3)oxidation and inferior N2selectivity.

关 键 词：NH_(3)-SCR USY zeolite Cu species Brønsted/Lewis acid centers Diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS) 

分 类 号：TQ426[化学工程] X701[环境科学与工程—环境工程]