Affiliation:
1. Department of Chemical Engineering Kyoto University Katsura, Nishikyo Kyoto 615–8510 Japan
2. Institute of Particle Technology Friedrich‐Alexander‐Universität Erlangen‐Nürnberg 91058 Erlangen Germany
3. Institute of Micro‐ and Nanostructure Research (IMN) & Center for Nanoanalysis and Electron Microscopy (CENEM) Friedrich‐Alexander‐Universität Erlangen‐Nürnberg 91058 Erlangen Germany
4. Erlangen Center for Interface Research and Catalysis Friedrich‐Alexander‐Universität Erlangen‐Nürnberg 91058 Erlangen Germany
Abstract
AbstractMetal–organic frameworks (MOFs) are microporous adsorbents for high‐throughput gas separation. Such materials exhibit distinct adsorption characteristics owing to the flexibility of the crystal framework in a nanoparticle, which can be different from its bulk crystal. However, for practical applications, such particles need to be compacted into macroscopic pellets, creating mass‐transport limitations. In this work, this problem is addressed by forming materials with structural hierarchy, using a supraparticle‐based approach. Spherical supraparticles composed of nanosized MOF particles are fabricated by emulsion templating and they are used as the structural component forming a macroscopic material. Zeolitic imidazolate framework‐8 (ZIF‐8) particles are used as a model system and the gas‐adsorption kinetics of the hierarchical material are compared with conventional pellets without structural hierarchy. It is demonstrated that a pellet packed with supraparticles exhibits a 30 times faster adsorption rate compared to an unstructured ZIF‐8 powder pellet. These results underline the importance of controlling structural hierarchy to maximize the performance of existing materials. In the hierarchical MOFs, large macropores between the supraparticles, smaller macropores between individual ZIF‐8 primary particles, and micropores inherent to the ZIF‐8 framework collude to combine large surface area, defined adsorption sites, and efficient mass transport to enhance performance.
Funder
Japan Society for the Promotion of Science
Deutsche Forschungsgemeinschaft
Subject
Mechanical Engineering,Mechanics of Materials,General Materials Science
Cited by
2 articles.
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