A are likely to last for at least

A sufficient, secure and affordable supply of energy is one of the major problems thathumanity faces on the turn of the 21st century, along with the provision of food,access to clean, drinkable water and appropriate living spaces. While fossil fuels havefuelled progress since the Industrial Revolution, they are becoming scarcer and moredifficult to explore, which will inevitably impact upon their price. Proven fossil fuelreserves are likely to last for at least another century, but problems associated withtheir use, the most important of which is climate change due to greenhouse gasemissions, have prompted the study of low-carbon alternative sources of energy.Developed economies are currently facing a significant challenge, since they have todepart from their current energy system, which is based on energy conversion fromfossil fuels and underpin their economies on a low-carbon, sustainable energy system.Due to its abundance on the Earth’s crust and the fact that it does not release anyharmful emissions, hydrogen is being considered as a possible wide-scale energyvector, and would fit ideally within this low-carbon sustainable energy system. Thereare still major technical and scientific hurdles to overcome, arguably the mostimportant of these is how to efficiently, economically and securely store hydrogen forlater use. Storage of hydrogen is an area that has received considerable attention in thelast decade and has been the driver for many interesting scientific developments. Anarea that has known substantial development is the synthesis and study of new porousmaterials for gas storage and separation, with newly synthesised materials such asmetal-organic frameworks garnering widespread attention from the scientificcommunity in recent years. The number of different porous materials grows by theday and many of these materials have been identified as promising hydrogen storagematerials. However, operating conditions are still stringent, and due to hydrogen’sphysical properties, significant storage in a porous material only occurs at moderatepressures (above 0.1 MPa) and cryogenic temperatures (usually 77 K).