Coaxial 3D Printing of Zeolite‐Based Core–Shell Monolithic Cu‐SSZ‐13@SiO2 Catalysts for Diesel Exhaust Treatment

• Published in: Advanced materials (Weinheim) 2024-04, Vol.36 (17), p.e2302912-n/a
• Main Authors: Wei, Yingzhen, Wang, Shuang, Chen, Mengyang, Han, Jinfeng, Yang, Guoju, Wang, Qifei, Di, Jiancheng, Li, Hongli, Wu, Wenzheng, Yu, Jihong
• Format: Article
• Language: English
• Subjects: 3-D printers; Catalysts; Chemical reduction; coaxial 3D printing; Core-shell structure; Cu‐SSZ‐13 zeolite; Diffusion layers; Honeycomb structures; Metal oxides; monolithic catalysts; NH3‐SCR; Porous materials; Selective catalytic reduction; Shell stability; Silicon dioxide; Three dimensional printing; Zeolites
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.202302912

Core–shell catalysts with functional shells can increase the activity and stability of the catalysts in selective catalytic reduction of NOx with ammoniax. However, the conventional approaches based on multistep fabrication for core–shell structures encounter persistent restrictions regarding strict synthesis conditions and limited design flexibility. Herein, a facile coaxial 3D printing strategy is for the first time developed to construct zeolite‐based core–shell monolithic catalysts with interconnected honeycomb structures, in which the hydrophilic noncompact silica serves as shell and Cu‐SSZ‐13 zeolite acts as core. Compared to a Cu‐SSZ‐13 monolith which suffers from the interfacial diffusion, the SiO2 shell layer can increase the accessibility of active sites over Cu‐SSZ‐13@SiO2, resulting in a 10–20% higher NO conversion at200−550 °C under 300 000 cm3 g−1 h−1. Meanwhile, a thicker SiO2 shell enhances the hydrothermal stability of the aged catalyst by inhibiting the dealumination and the formation of CuOx. Other representative monolithic catalysts with different topological zeolites as shell and diverse metal oxides as the core can be also realized by this coaxial 3D printing. This strategy allows multiple porous materials to be directly integrated, which allows for flexible design and fabrication of various core–shell monolithic catalysts with customized functionalities. A facile coaxial 3D printing strategy is developed to fabricate core–shell Cu‐SSZ‐13@SiO2 catalysts with superior mass transfer efficiency and high hydrothermal stability for NH3‐assisted selective catalytic reduction. This coaxial 3D printing technology allows for the flexible design and construction of zeolite‐based core–shell monoliths with the advantages of easy fabrication, universal applicability, and judicious integration of functional composites.