Ammonia storage materials for nitrogen recycling hydrogen and energy carriers

Abstract Ammonia (NH3) has large gravimetric and volumetric H2 densities and has advantages as hydrogen and energy carriers. Unfortunately, NH3 is a deleterious substance. NH3 storage technology is essentially necessary to suppress leaked NH3 in the atmosphere. Many kinds of NH3 storage materials, which are metal halides, borohydrides, ammonia borane, proton-based materials, porous materials and water have been studied. In those materials, water easily collects leaked NH3 because of the large diffusion coefficient of NH3. H+ in proton-based materials can react with lone electron pair of NH3 to form NH4+ and has low NH3 vapor pressure in the atmosphere. Insoluble proton-based materials also can remove nitrogen (NH3–N) from NH3 water. Therefore the NH3 removal system combined water and insoluble proton-based materials will be candidate for the leaked NH3 concentration lowering in the atmosphere by suppression of water pollution.