Computational design enables uni duo’s materials science breakthrough

The work by researchers at the universities of Liverpool and Southampton to develop non-metal organic porous framework materials offers potential applications for a variety of areas.

These could offer an alternative to metal organic frameworks (MOFs) – porous, crystalline materials comprised of metals connected by organic linker compounds. The 95,000 MOFs identified to date have applications for catalysis, gas separation and energy storage.

The metal-free organic porous frameworks (N-MOFs) have demonstrated effectiveness for the capture of iodine, used for example in the nuclear industry. Other applications areas could include proton conduction, catalysis, water capture and hydrogen storage suggest the scientists in their paper published in Nature.

The research team suggest it should in time be possible to extend the materials in cases where organic linkers are connected by ions made up of other common non-metal elements such as nitrogen, oxygen and sulphur.

Research drew on complementary expertise in the discovery of new materials and robotics from the University of Liverpool alongside computational modelling expertise from the University of Southampton.

Leading the Liverpool university team is department of chemistry professor and academic director of its £81 million Materials Innovation Factory, Andrew Cooper.

Cooper, who is also director of the Leverhulme Research Centre for Functional Materials Design and co-director of national research hub for the use of artificial intelligence in chemistry, AIChemy, said of the potential developments from the project: 

“This work opens up a range of possibilities. Our approach uses non-metal anions as nodes to build frameworks… There are more anions available than there are metals in the periodic table, so the space to search for new materials is huge.”

Professor of chemical modelling at Southampton school of chemistry Graeme Day’s research group, which is developing predictive computational methods for the organic solid state, addressed a key problem when using the non-metallic organic frameworks.

Namely, whereas metal nodes in MOFs direct the framework structure – in a manner likened to joints in a scaffold, with a predictable geometry that allows those frameworks to be designed for specific applications ­– non-metallic salts’ interactions are much less directional.

Explained Day: “We guided the discovery of these materials using a computational method called crystal structure prediction. This allows us to predict which non-metal salts will form stable porous frameworks, which salts will not, and to anticipate the precise crystal structure in advance of experimental work.

“We don’t have to assume a specific geometry for the joints in the framework, which is a fundamental principle in MOF chemistry.”