Synthesis and reversible structural transformations observed in 1. Solvothermal preparation of 1DMF from dpt, 1,3-bib and Co(NO3)2·6H2O yields purple crystals with N,N-DMF (shown in space-filling representation) located in discrete cavities of 410 Å3 (the cavities are shown as an orange surface). The inset on the left shows the position of the chelating dpt ligand. In situ activation of a single crystal of 1DMF (using an environment cell; see the corresponding photomicrograph) yields guest-free-phase 1Apohost where, as a result of rotation, the dpt ligand becomes mono-coordinated (see the inset on the right) and the guest-accessible cavities are reduced to 84 Å3. Subsequent gas loading of 1Apohost first with 1 bar of CO2 (bottom left) and then with 56 bar of CO2 (bottom right) leads to CO2 (discrete cavities of 360 Å3) and 1′′CO2 (discrete cavities of 373 Å3). Closer inspection of the cavities in 1ʹʹCO2 shows the cavities in very close proximity to one another, hinting at a potential transportation pathway. The CO2 gas molecules loaded into CO2 and 1ʹʹCO2 could not be crystallographically modeled. The dpt disorder in 1Apohost and CO2 has been omitted for clarity. Credit: Nature Chemistry (2023). DOI: 10.1038/s41557-022-01128-3

Researchers at University of Limerick in Ireland have discovered a new material that can 'trap and store' volatile gases.

The research team, which includes international collaborators in Japan, the US and South Africa, have discovered a new class of porous materials or sorbents for trapping and storing volatile gases.

The discovery has just been published in the journal Nature Chemistry.

The team is led by Dr. Varvara Nikolayenko, formerly of the Department of Chemical Sciences and UL's Bernal Institute, now working at Bayer AG and Professor Michael Zaworotko, Bernal Chair of Crystal Engineering and Science Foundation of Ireland Research Professor at UL's Bernal Institute.

The discovery is an extremely important one as there is an urgent need find to better ways to store volatile fuel (e.g., hydrogen and ) and medicinal (e.g., oxygen and ) gases, which currently require very high pressures or very low temperatures.

"Traditional sorbents have interconnected holes and pores like a sponge. The new sorbents we have discovered are more like Swiss cheese in that they have empty space, but they are not interconnected by pores," explained Professor Zaworotko.

"Our new materials point towards an alternate approach to store such gases which is both less energy intensive and safer," he added.

The research team said the key findings included that the so-called 'Swiss cheese' sorbent expands when it is exposed to gases with very little structural rearrangement and thereby captures increasingly large quantities of gas as pressure is increased.

"The changes in the sorbent are reversible so the gas can be easily removed, and the sorbent can be recycled for further use," explained Dr. Nikolayenko.

"It is counterintuitive to expect a sorbent which has no pores to have the ability to trap volatile gases. This raises the question of whether there are many more such sorbents that are hiding in plain sight," she added.

The latest discovery builds on research Professor Zaworotko is carrying out at UL's Bernal Institute in crystal engineering to tackle grand climate challenges.

Last year, Professor Zaworotko and his team developed a that has the ability to capture from the air.

That material is capable of capturing trace amounts of benzene, a toxic pollutant, from the air and crucially use less energy than existing materials, which could revolutionize the search for clean air.

Professor Zaworotko and his team have also previously discovered a material with favorable properties for absorbing and releasing water from the atmosphere that could revolutionize dehumidification systems in buildings and the availability of water in regions of drought.

He explained, "People in science are driven by a dream. The dream is, in almost all cases, to have a positive impact on society. Water purification, , cheaper and better pharmaceuticals, are just three examples of where crystal engineering could be the key and the pieces of that jigsaw puzzle are coming together now."

More information: Varvara I. Nikolayenko et al, Reversible transformations between the non-porous phases of a flexible coordination network enabled by transient porosity, Nature Chemistry (2023). DOI: 10.1038/s41557-022-01128-3

Journal information: Nature Chemistry