Strategies for the Improvement of Hydrogen Physisorption in Metal-Organic Frameworks and Advantages of Flexibility for the Enhancement

To overcome the environmental issues arising from the burning of fossil fuel, an alternative effective source of energy is required. Hydrogen energy is one such alternative which can pave the purpose of interest. For a successive replacement of fossil fuel by hydrogen energy, hydrogen storing, especially in a vehicular system, is highly required and it is still a major challenge. A wide range of materials have been used for hydrogen storing. Metal-organic framework is one of them, which have been studied extensively both from academic and industrial viewpoint. These studies show that several metal-organic frameworks (MOFs) have excellent physisorption ability but normally at a very low temperature. To improve this at ambient conditions, various strategies have been introduced so far for MOFs, although an important aspect of external stimuli-responsive flexible or dynamic frameworks, have not been studied systematically. There are various advantages of the use of dynamic MOFs for hydrogen physisorption and sometimes helpful to overcome socio-economical barrier connected to this alternative energy source. In this highlight, prior strategies to improve hydrogen storage in MOF with special importance on external stimuli-responsive flexible MOF and their perspective importance in hydrogen storage have been discussed.