Porous Functional Nanomaterials for Continuous Flow Catalysis

With the advancement of green chemistry and process intensification, continuous flow technology has emerged as a powerful tool in the manufacturing of fine chemicals and pharmaceuticals. Owing to their highly regular porous architectures, diverse chemical compositions, and excellent catalytic activity, porous materials have proven to be ideal supports and catalytic platforms for continuous flow catalysis. This review systematically summarizes the recent progress in the design and application of porous materials in continuous flow catalysis, with a focus on several major structural categories, including metal-organic frameworks, covalent organic frameworks/polymers, cages, porous silicates, monoliths, and polymeric carbon nitrides. It also covers various reactor types, including fixed bed, packed bed, and microreactors. Special emphasis is placed on elucidating the relationships among pore structure, electronic structure, active sites, and reaction-diffusion kinetics of porous catalysts within flow reactors. Their practical applications are outlined in areas such as selective catalysis of small molecules, photocatalysis, photothermal catalysis, and multistep cascade reactions in bioconversion processes. Furthermore, focusing on the technical challenges encountered during the industrial scale-up of continuous flow systems based on porous catalysts, this review examines key issues such as insufficient precise control over structure and function, limitations in the compatibility of particle and overall morphology design, difficulties in regulating low-pressure-drop fluid dynamics, and the challenge of maintaining high catalytic stability over extended operation. It also provides a systematic analysis of potential solutions to these problems. Finally, current challenges and future directions in the field are discussed, underscoring the pivotal role of porous materials in flow chemistry. It is hoped that this review will stimulate further research on the application of porous materials in continuous flow catalysis and facilitate the rational design of novel heterogeneous porous catalysts for industrial applications.