吉林大学于吉红团队报道了Cu-OFF/ERI沸石——共生结构协同促进NH₃选择性催化还原NOx。相关研究成果发表在2024年3月11日出版的国际学术期刊《美国化学会杂志》。

Cu-SSZ-13已用于商业化氨选择性催化还原（NH₃-SCR），以去除柴油废气中的NOx。由于其合成通常需要有毒且昂贵的有机模板，因此发现具有无有机模板合成和与Cu-SSZ-13相当，甚至优于NH₃-SCR活性的替代铜基沸石催化剂具有重大的学术和工业意义。

该文中，研究人员证明了通过无有机模板法合成的具有菱钾沸石（OFF）和毛沸石（ERI）共生结构的，比Cu-ERI和Cu-OFF以及Cu-SSZ-13具有更好的催化性能Cu-T。结构表征和密度泛函理论计算表明，共生结构促进了更多孤立的Cu²⁺位于共生界面的6MR处，使Cu-T的水热稳定性优于Cu-ERI和Cu-OFF。

引人注目的是，水热老化后Cu-T的低温活性显著提高，而Cu-ERI和Cu-OFF的电导率显著降低。基于原位漫反射红外傅立叶变换光谱分析和密度泛函理论计算，原因可归因于在标准SCR反应条件下，在Cu-T的ERI多晶型中的CuxOy物种上形成的NH₄NO_3，在共生界面的Brnsted酸位点的帮助下经历了快速的SCR反应途径。值得注意的是，Cu-T在超过90%的催化活性下表现出比Cu-SSZ-13更宽的温度窗口（新鲜处理为175–550比175–500°C，水热处理为225–500比250–400°C）。

根据沸石共生结构的相互作用，这项工作为设计高性能NH₃–SCR催化剂提供了新的方向。

附：英文原文

Title: Cu-OFF/ERI Zeolite: Intergrowth Structure Synergistically Boosting Selective Catalytic Reduction of NOx with NH3

Author: Jinfeng Han, Junyan Li, Wenru Zhao, Lin Li, Mengyang Chen, Xin Ge, Sen Wang, Qingling Liu, Donghai Mei, Jihong Yu

Issue&Volume: March 11, 2024

Abstract: Cu-SSZ-13 has been commercialized for selective catalytic reduction with ammonia (NH3–SCR) to remove NOx from diesel exhaust. As its synthesis usually requires toxic and costly organic templates, the discovery of alternative Cu-based zeolite catalysts with organotemplate-free synthesis and comparable or even superior NH3–SCR activity to that of Cu-SSZ-13 is of great academic and industrial significance. Herein, we demonstrated that Cu-T with an intergrowth structure of offretite (OFF) and erionite (ERI) synthesized by an organotemplate-free method showed better catalytic performance than Cu-ERI and Cu-OFF as well as Cu-SSZ-13. Structure characterizations and density functional theory calculations indicated that the intergrowth structure promoted more isolated Cu2+ located at the 6MR of the intergrowth interface, resulting in a better hydrothermal stability of Cu-T than Cu-ERI and Cu-OFF. Strikingly, the low-temperature activity of Cu-T significantly increased after hydrothermal aging, while that of Cu-ERI and Cu-OFF substantially decreased. Based on in situ diffuse reflectance infrared Fourier transform spectra analysis and density functional theory calculations, the reason can be attributed to the fact that NH4NO3 formed on the CuxOy species within ERI polymorph of Cu-T underwent a fast SCR reaction pathway with the assistance of Brnsted acid sites at the intergrowth interfaces under standard SCR reaction conditions. Significantly, Cu-T exhibited a wider temperature window at a catalytic activity of over 90% than Cu-SSZ-13 (175–550 vs 175–500 °C for fresh and 225–500 vs 250–400 °C for hydrothermal treatment). This work provides a new direction for the design of high-performance NH3–SCR catalysts in terms of the interplay of the intergrowth structure of zeolites.

DOI: 10.1021/jacs.3c13855

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.3c13855