Keeping out the oxygen

Hydrogen, the lightest of the elements, is expected to play a major role in our future energy economy. Its staggering energy content of 142 MJ kg-1 exceeds that of petroleum by a factor of three. Moreover, the combustion of hydrogen, as well as its use in electricity-producing fuel cells, is not associated with carbon dioxide emissions. Furthermore, even though the majority of hydrogen used today still comes from fossil fuels, it can also be produced using renewable energy sources, such as biomass and solar or wind power. Despite these clear merits, however, the widespread use of hydrogen, which is a gas under ambient conditions, is still limited by a lack of technologies to store and transport it in a compact, safe and efficient manner. Writing in Nature Materials, Jeon and co-workers now report that a composite of magnesium nanoparticles embedded in a gas-selective polymer can serve as a stable and high-capacity hydrogen reservoir.