Scalable and sustainable synthesis of metal-organic frameworks (MOFs)

Summary

Metal-organic frameworks (MOFs) and related framework materials are an important materials solution for the energy transition, including exciting prospects for gas storage (hydrogen and carbon dioxide), energy efficient chemical separations, and for use in membranes in fuel cells and batteries. With this overarching aim in mind, scalable but also sustainable production routes are needed to deliver materials with the required properties at scale. This project will build on the development of a water-based flow reactor platform for MOF synthesis at Leeds. In particular, the project will look to optimise the reactor flow patterns, investigate the interactions of additional stimuli (e.g. ultrasound), and explore possibilities in self-optimisation with on- or in-line analysis. The rich variety of framework chemistries presents a guiding challenge for developing a generalisable reactor design, and so this project will look to develop syntheses and construct new reactors for a variety of target framework materials. By linking synthesis through to evaluation of functional properties (e.g. gas sorption and electrochemical analyses), the project will balance simultaneous objectives including production rate and materials performance requirements.

Additional detail:

Coordination polymers encompass a rich variety of materials including metal-organic frameworks (MOFs) as well as covalent organic frameworks and hydrogen-bonded organic frameworks. These materials are built from nodes (e.g. metal ions or clusters in MOFs) bridged by organic linker molecules, including diverse functional group chemistries spanning carboxylate, imidazolate, phosphonate, and sulfonate linkers among many others.

Highly crystalline framework materials stand out for their structurally defined porosity and record surface areas, important for applications in gas storage [1], membrane-based chemical separations (as an alternative to energy-intensive distillations) [2], and catalysis [3]. Their tuneable functional group chemistry also makes them excellent candidates for dense materials applications including proton and ion conduction in membranes for fuel cells and batteries.

At Leeds, we have recently developed a class of sulfonate coordination polymers and MOFs for proton exchange membrane applications [4, 5], establishing both reactors for enhanced space time yield as well as probing the materials properties using electrochemistry. This project has culminated in a ultrasound-assisted water-based two-phase flow reactor for MOF syntheses applied to not only sulfonates but also carboxylate and imidazolate examples.

This project will leverage this underpinning work to look at how reactor design affects syntheses for varied MOF chemistries and structures, with a particular view to also automate the operation and optimisation of the reactor platform, such as through self-optimising control and on- or in-line feedback for reactor control.

The project will include work across the School of Chemical and Process Engineering as well as the School of Chemistry and the Bragg Centre for Materials Research at the University of Leeds, offering lots of support and teams of experienced researchers across intersecting elements of the project.

References:

[1] R. Freund et al. Angew. Chem. Int. Ed. 2021, 60, 23975-24001. https://doi.org/10.1002/anie.202106259.

[2] Q. Qian et al. Chem. Rev. 2020, 120, 8161-8266. https://doi.org/10.1021/acs.chemrev.0c00119.

[3] A. Griffiths et al. Nanoscale 2023,15, 17910-17921. https://doi.org/10.1039/D3NR03634K

[4] C. Sun et al. Chem. Engin. J. 2023, 474, 145892. https://doi.org/10.1016/j.cej.2023.145892

[5] C. Sun et al. J. Mater. Chem. A 2024, 12, 18440-18451. https://doi.org/10.1039/D4TA01716A.

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