摘要
CuO/Al_(2)O_(3)催化剂为低温SCR催化剂,在其表面添加In组分,并用于丙烯选择性催化还原(C_(3)H_(6)-SCR)氮氧化物(NO_(x))的研究。结果表明,负载CuIn的催化剂表现出最好的反应活性,在350°C时NO_(x)转化率可达到62%。XPS表征结果显示,同时负载In改变了Cu的化合价态和表面氧的分布,提高了催化剂表面Cu^(2+)和化学吸附氧的比例。H_(2)-TPR和NO+O_(2)-TPD结果表明,同时负载CuIn能提高催化剂氧化还原性,也促进了NO_(x)的吸附,催化剂表面生成大量的亚硝酸盐/硝酸盐。反应机理研究表明,C_(3)H_(6)-SCR过程沿着L-H反应路径进行,同时负载CuIn能促进C_(3)H_(6)的快速氧化,并有助于催化剂表面甲酸盐和乙酸盐的形成。因此,Cu^(2+)和化学吸附氧比例的提高,会增强催化剂的氧化还原性能,从而加速甲/乙酸盐的形成,这可能是促进C_(3)H_(6)-SCR低温活性得以提高的主要原因。本研究可为应用于柴油车尾气控制技术的低温SCR催化剂开发提供参考。
CuO/Al_(2)O_(3) catalyst was a low-temperature SCR catalyst.In this paper,In was added to the surface of CuO/Al_(2)O_(3) catalyst and used for selective catalytic reduction of nitrogen oxides(NO_(x))by propylene(C_(3)H_(6)-SCR).The results showed that the catalyst supported with CuIn exhibited the best activity,with NO_(x) conversion up to 62%at 350°C.XPS characterization results showed that the loading of In changed the valence state of Cu and the distribution of oxygen on the surface,and increased the ratio of Cu^(2+)and chemisorbed oxygen on the catalyst surface.The results of H2-TPR and NO+O_(2)-TPD showed that loading CuIn could improve the reducibility of the catalyst and promote the adsorption of NO_(x),and a large number of nitrite/nitrate species were formed on the catalyst surface.Studies of reaction mechanism showed that C_(3)H_(6)-SCR process followed L-H reaction mechanism.Doping CuIn promoted the rapid oxidation of C_(3)H_(6) and contributed to the formation of formate and acetate on the catalyst surface.Therefore,the increase of the ratio of Cu^(2+)and chemisorbed oxygen would enhance redox performance of the catalyst and accelerate the rapid formation of formate/acetate,which might be the main reasons for the improvement of activity of C_(3)H_(6)-SCR in low temperature range.This study can provide reference for the development of low temperature SCR catalyst applied in diesel vehicle exhaust control technology.
作者
刁凡
王驰中
余杰
于喆
赵菲琳
李振国
常化振
DIAO Fan;WANG Chizhong;YU Jie;YU Zhe;ZHAO Feilin;LI Zhenguo;CHANG Huazhen(School of Environment and Natural Resources,Renmin University of China,Beijing 100872,China;National Engineering Laboratory for Mobile Source Pollution Emission Control Technology,China,Automotive Technology&Research Center Co.Ltd,Tianjin 300300,China)
出处
《环境工程学报》
CAS
CSCD
北大核心
2022年第9期2901-2910,共10页
Chinese Journal of Environmental Engineering
基金
国家自然科学基金重点项目(51938014)
国家自然科学基金面上项目(22176217)。
