Synthetic Control over MOF Particle Growth and Surface Chemistry

Non-technical Summary

Membranes based on metal-organic frameworks (MOFs), which are three-dimensional (3-D) organic/inorganic compounds, attract intense interest for industrial petroleum refining and gas separations due to their exceptional tunability and synthetic diversity. For MOFs to reach widespread attraction and implementation in the industrial sector, however, researchers will be required to go beyond 3-D MOFs and develop new types of MOF nanoparticles, as they exhibit superior separation performance and generate membranes with superior stability.

For the past two decades, bulk powders of MOFs occupied the focus of academic MOF research, but very recent attention has turned to preparing MOF nanoparticles and polymer composites with precise control of particle sizes. Despite preliminary demonstrations of the great potential of MOF nanoparticles, key fundamental questions remain for achieving reproducible control over MOF particle composition and for understanding how particle size and composition impact membrane performance.

With this project, supported by the Solid State and Materials Chemistry program in the Division of Materials Research at NSF, Prof. Carl Brozek at the University of Oregon and his research group will investigate the chemical principles that control the precise sizes and compositions of MOF nanocrystals. Mechanistic growth models will be developed in the context of growth models established for other classes of materials so that these results inform the broad field of materials chemistry.

Similarly, the synthetic techniques pursued in this proposal will influence materials design beyond MOF particles, by outlining fundamental tools for molecular control over materials across multiple size regimes. The proposed research is practically relevant to society because precise control over MOF nanocrystal sizes will open new frontiers in improved gas separation membranes for industry and the opportunity for elevating MOF application performance to becoming practically relevant.

Technical Summary

This project, supported by the Solid State and Materials Chemistry program in the Division of Materials Research at NSF, will investigate the fundamental growth mechanisms of metal-organic framework (MOF) particles, develop methods to control particle surface chemistry for enhancing their colloidal stability and interfacing with polymer composites, and understand the impact of size and surface composition on molecular- and charge-transport properties. Tackling this goal will require basic investigation into the parameters that dictate particle sizes, defect incorporation, and surface functionalization.

Insight into controlling prenucleation crystal growth of materials in general, reproducible synthesis of MOF-based heterostructure composites, and improving the practical relevance of MOF materials will result from this research. Broader impacts of this proposal include 1) integrating these research aims into educational outreach initiatives that communicate the science of carbon capture technology to underserved students, 2) fostering interdisciplinary training programs that pairs chemistry with architecture students to design air-purification modules, 3) sponsoring industry-academia seminar series on MOF-based carbon-capture, and 4) implementing a teaching course on designing outreach initiative offered year-round to University of Oregon (UO) chemistry PhD students.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.