Developing Switchable and Self-Accelerating MOFs for Toxic Gas Adsorption

Lead Research Organisation: University of St Andrews
Department Name: Chemistry


Metal-organic frameworks are some of the most exciting new materials to have been prepared over the last two decades. They comprise metals ions or metal clusters linked by organic groups to provide highly porous materials with surface areas approaching 6000m2/g. These materials have aroused great interest in many different areas, from hydrogen and methane storage for energy to drug and medical gas delivery agents. Of particular relevance to the defense industries is their ability to adsorb toxic gases in large amounts.

In St Andrews we have developed a particularly interesting MOF called STAM-1 (Figure 1), which shows some very unusual properties.1 We published a paper in Nature Chemistry that showed 'switchable' adsorption, a unique property where the adsorption between two channels can be controlled. We have since followed up this work by showing that a composite STAM-1/silica material is the only MOF that shows increased adsorption of toxic gases like ammonia in the presence of water (Figure 2), which is usually a limiting feature of MOF adsorption as the water competes very successfully against other gases for adsorption sites. STAM-1 is also much more stable than other materials of its type, and so the material shows great promise for further application.
1. To prepare a series of materials with the STAM-1 topology but different chemistry
2. To understand how toxic gases interact with the materials. In particular we will complete mechanism studies using in situ X-ray diffraction and other techniques to study whether it is the switchable nature of the pores that causes the observed improvement.
3. To understand how the preparation of silica/MOF composites improves the properties of the materials, especially in the presence of moisture


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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/N50936X/1 30/09/2015 29/09/2020
1690651 Studentship EP/N50936X/1 30/09/2015 31/03/2019 Lauren McHugh
Description In the project so far, a series of new metal-organic frameworks (porous materials) have been developed for the application of air purification. A manuscript was recently published in the journal Nature Chemistry regarding the structure and properties of a member of this series and a further publication shall be submitted prior to completion of this project, along with one on a related structure. Current air purification technologies typically utilise another porous material: activated carbon and a number of new activated carbon-MOF composite materials have recently been synthesised, combining the adsorptive properties of both components. A manuscript describing the the properties of these materials is currently in preparation.
Exploitation Route The materials shall continue to be tested against various chemicals upon completion of this project and collaboration between my industrial sponsors: Dstl and the University of St Andrews shall remain active. Further students may continue with this work upon completion and we have interest from industry regarding these materials.
Sectors Aerospace, Defence and Marine,Chemicals,Environment,Manufacturing, including Industrial Biotechology