Catalytic ammonia decomposition to produce hydrogen: A mini-review

•Hydrogen production methods through ammonia dehydration are introduced.•Applicable ammonia dehydration technologies are critically reviewed.•Research opportunities and needs to improve each technology for future application are discussed. 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.