Easy, all you need is a Metal Organic Framework (MOF) to capture the gases! For those who have not spent years researching crystal engineering with Professor Mike Zaworotko, Bernal Chair of Crystal Engineering in UL, MOFs are man-made crystals, designed from scratch with a huge surface area. Just like a sponge they are full of holes, that can attract and capture large volumes of gas. In fact, some of these crystals are so well designed that a piece small enough to fit in your pocket, can have the same surface area as 40 tennis courts*. This is very exciting work when you consider the large volumes of excess carbon dioxide being released into the atmosphere every year.

Crystal engineering is a relatively new branch of scientific research and Prof Zaworotko is one of the pioneering figures in this field. A professor in crystal engineering at the university of Limerick, Professor Zaworotko also acts as chair for the Bernal Institute and director of the Science Foundation Ireland funded Synthesis and Solid State Pharmaceutical Centre. The principle behind crystal engineering is to design materials by treating molecules as Lego® blocks so that they can perform a specific function based on a specific need. The researchers use combinations of organic and inorganic building blocks to create these new materials, carefully controlling the structure and properties as they go. One of the most common design functions of these materials is the capture and storage of specific gases. Crystal engineers, just like architects, can design MOFs so that the size of the pores are just right to makes them selective to certain gases but not others. These traits make these “designer MOFs” useful for gas storage and, especially, separation.

One of the main focuses of Prof Zaworotko’s research is on carbon capture by adsorption, a means of trapping and storing large amounts of carbon dioxide (CO2). His team have developed a family panel of materials known as TIFSIX and SIFSIX MOFs that are so selective towards CO2 that they can spontaneously capture CO2 from air. Potentially this stored CO2 could be used in the downstream production of methanol or hydrocarbons for fuel and they could enable new technologies that are carbon neutral or even carbon negative.

The scope of these materials does not just lie with carbon capture; they are being explored for their potential in a number of industries. More than 30% of the world’s energy is used for purification, for example purification of water, crude oil, natural gas and chemicals for industry. MOFs present a more effective means of purifying these components and could have a massive impact on the energy efficiency of these processes. They are also being used in the storage of natural gas and methane for gas-powered vehicles. Roughly, 20 per cent of all industrial vehicles already run on natural gas but at high pressures or low temperatures. With the massive storage capacity of MOFs, they offer a much more efficient alternative for fuel storage.

 

*or 2 rugby pitches!