摘要
采用硅烷化改性NH3选择性催化还原NOx催化剂CuCe/BEA,以提高催化剂的水热稳定性。X射线衍射、扫描电子显微镜和27Al核磁共振谱图等研究证实,硅烷化改性明显抑制BEA分子筛骨架中Si-O-Al键的水解,保持其结构完整,从而有效提高水热处理后CuCe/BEA的催化活性。氨气-程序升温脱附和原位漫反射傅里叶变换红外光谱研究结果表明,硅烷化改性的催化剂由于保持更完整的骨架结构能够形成更多的酸性位点。此外,氢气-程序升温还原和X射线光电子能谱测试表明,硅烷化改性有利于提高活性铜物种的分散性。因此,相比于CuCe/BEA催化剂,硅烷化改性的CuCeSi/BEA催化剂具有更多的酸性位点和高度分散的Cu物种,共同促进了催化剂的水热稳定性。
The hydrothermal stability of CuCe/BEA catalyst is improved by its silanization for selective catalytic reduction of NOx with NH3(NH3-SCR).The results indicate that the silanization modification effectively enhances the catalytic activity of CuCe/BEA after the hydrothermal treatment due to significantly inhibit the hydrolysis of Si-O-Al bonds from the BEA skeleton to maintain structural integrity,revealed by X-ray diffraction(XRD),scanning electron microscope(SEM)and 27Al nuclear magnetic resonance(27Al NMR).More complete skeleton structure of CuCeSi/BEA catalyst results in the formation of more acid sites after the hydrothermal treatment,confirmed by NH3-temperature programmed desorption(NH3-TPD)and in situ diffuse reflectance infrared transform spectroscopy(in situ DRIFTS).Moreover,H2-temperature programmed reduction(H2-TPR)and X-ray photoelectron spectrum(XPS)show that silanization is beneficial to facilitate the dispersion of active copper ions after the hydrothermal treatment.Therefore,more acid sites and highly dispersed Cu species together contribute to higher hydrothermal stability of silanized CuCeSi/BEA than CuCe/BEA catalyst.
作者
徐书浩
林青瑾
刘双
刘静莹
徐海迪
王健礼
陈耀强
XU Shu-Hao;LIN Qing-Jing;LIU Shuang;LIU Jing-Ying;XU Hai-Di;WANG Jian-Li;CHEN Yao-Qiang(Sichuan Provincial Environmental Protection Environmental Catalytic Materials Engineering Technology Center,College of Chemistry,Sichuan University,Chengdu 610064,China;State Key Laboratory of Polymer Materials Engineering,Institute of Polymer Science,Sichuan University,Chengdu 610064,China;Institute of New Energy and Low-Carbon Technology,Sichuan University,Chengdu 610064,China;National Engineering Laboratory for Mobile Source Emission Control Technology,China Automotive Technology&Research Center,Tianjin 300300,China;Sichuan University FGD(Flue Gas Desulfurization)State Engineering Research Center,Chengdu 610064,China)
出处
《无机化学学报》
SCIE
CAS
CSCD
北大核心
2020年第12期2385-2394,共10页
Chinese Journal of Inorganic Chemistry
基金
国家自然科学基金(No.21802099)
四川省科技计划(No.2019YFS0498)
移动源污染排放控制技术国家工程实验室(No.NELMS2017A06)资助项目。
关键词
硅烷化
分子筛
水热稳定性
结构活性关系
多相催化
silanization
zeolite
hydrothermal stability
structure-activity relationships
heterogeneous catalysis
