Reaserch progress on 3D printing of monolithic catalyst

The integrated structure of monolithic catalysts not only reduces flow resistance and enhances mass and heat transfer efficiency，but also overcomes the inherent limitations of granular catalysts，thereby endowing them with more efficient and stable catalytic performance. They have been extensively employed in fields such as space stations，manned spacecraft and satellite attitude and orbit control. However，conventional molding techniques fail to achieve customized production of complex macroscale structures and flexible regulation of microscale pore structures during catalyst preparation，and the backwardness of preparation processes has hindered the further development of monolithic catalysts. Currently，scholars at home and abroad have begun to adopt additive manufacturing technology for the design and fabrication of monolithic catalysts，among which the design and selection of catalyst 3D structure，molding method and carrier material according to application requirements are the key research focuses. This paper firstly outlines the application limitations of traditional molding methods for monolithic catalysts and highlights the technical advantages of additive manufacturing techniques. Subsequently，it elaborates on the design and regulation methods of catalyst structures，analyzes the structural characteristics and post-processing methods of carriers under different molding approaches，and summarizes common printing materials and carrier properties. Finally，based on the practical application status of 3D-printed monolithic catalysts in aerospace and other industries，this paper systematically prospects the future development trends of catalyst additive manufacturing，as well as the core challenges，including the protection of catalyst pore structures，maintenance of specific surface area and loading of active components during high-temperature molding.