Arguably, this focus may have diminished the consideration of reversibility, cost, and practicality of use of these materials. In response to this challenge, there has been a significant research effort over the past 15 years that has focused on new chemical hydrogen storage materials, particularly solid-state materials which offer impressive volumetric and gravimetric hydrogen densities. Current high-pressure (∼700 bar) storage is expensive and energy-intensive, and imposes practical restrictions on tank dimensions. Despite these advantages, its use has been hindered by the lack of an effective and efficient method for its storage.
#MAKE CRACK WITH AMMONIA FREE#
Hydrogen (H 2) is an attractive chemical fuel, with very high gravimetric energy content (120 MJ/kg) and an emissions profile free from carbon dioxide. Indeed, high-density, affordable, and efficient hydrogen storage is one of the key steps in the realization of a hydrogen-based energy sector. The reverse reaction may have a similarly transformative potential, where the decomposition of ammonia into nitrogen and hydrogen enables the provision of hydrogen for a low-carbon energy economy. The Haber−Bosch process for the industrial synthesis of ammonia has, over the past century, led to a global revolution in agriculture to the extent that almost half the crops grown across the world today depend on ammonia-based fertilizers.
As an abundant and inexpensive material, the development of NaNH 2-based NH 3 cracking systems may promote the utilization of NH 3 for sustainable energy storage purposes, they suggest. The scientists report that in variable-temperature NH 3 decomposition experiments using a simple flow reactor, the Na/NaNH 2 system shows superior performance to supported nickel and ruthenium catalysts, reaching up to a 99.2% decomposition efficiency with 0.5 g of NaNH 2 in a 60 sccm NH 3 flow at 530 ☌. The new process decomposes ammonia using the concurrent stoichiometric decomposition and regeneration of sodium amide (NaNH 2) via sodium metal (Na) this is a significant departure in reaction mechanism compared with traditional surface catalysts.
A paper on the process appears in the Journal of the American Chemical Society.
Researchers at the Rutherford Appleton Laboratory (RAL) in the UK are proposing a new type of process that is an alternative to the use of rare or transition metal catalysts for the cracking of ammonia (NH 3) to produce hydrogen. RAL researchers are proposing a new process for the decomposition of ammonia to release hydrogen that involves the stoichiometric decomposition and formation of sodium amide from Na metal.
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