Hydrogen is expected to become an important source of clean energy that does not result in CO2 emissions, and this is creating an urgent need to develop technologies to easily handle hydrogen in production, transport, storage, and use.
Hydrogen is a gas at normal temperatures and pressures. To liquefy, it must be cooled to less than -250 ℃ under high pressure, which is a major obstacle to mass transport and mass storage. At present, the development of materials as hydrogen carriers is being promoted; these can be used to efficiently transport and store hydrogen at low cost. Materials that can be used as hydrogen carriers include organic hydrides, ammonia, alcohols, and metals. Organic hydrides are compounds to which hydrogen is added to form aromatic compounds; these can be stored and extracted using catalysts - two examples are methylcyclohexane and decalin.