Catalytic ammonia decomposition to produce hydrogen: A mini-review

Hydrogen (H₂) is considered one of the most promising alternative energy resources instead of fossil fuels, serving as a clean energy carrier. Ammonia (NH₃) is regarded as a high percentage hydrogen carrier and utilized as an initial material for H₂ production. As for the H₂ production through NH₃ decomposition, there are various catalytic processes particularly using Ru- and Pd-based catalysts. The Ru- and Ni-based NH₃ decomposition catalysts have been studied due to synergetic effect of active metal phase in stabilizing unstable nitrogen intermediate species during NH₃ decomposition reaction. The Pd catalyst-based membrane reactors were developed to enhance H₂ separation from the product stream of NH₃ decomposition. Integrated systems combining Ru catalyst and Pd-based membrane were also explored to achieve a high yield of H₂ from NH₃. This review summarizes recent literatures on catalytic NH₃ decomposition to produce H₂. It probably provides useful insights into designing large-scale H₂ production processes.