Abstract: Hydrogen energy,as a clean and environmentally friendly renewable energy source,is attracting worldwide attention.However, the extremely low volume energy density andthe flammable and explosive characteristics of hydrogen bring difficulties and dangersto large-scale storage and transportation of hydrogen. Ammonia is a kind of carbon-free hydrogen carrier,which not only has high volume and mass energy density, but also has mature storage and transportation technology.On-site hydrogen productionfrom ammonia can solve the problems of hydrogen storage and transport, so ammonia hydrogen storage from ammoniais attracting a lot of attention. Currently, the most efficient catalyst for ammonia decomposition is ruthenium-based catalysts, but it can not be used in large scale because of its high price. Among the non-precious metal-based catalysts, Ni-based catalysts have the highest activity and relatively low cost,which are considered to have great application potential. However, Ru-based and Ni-based catalytic systems still havesome challenges in terms of activity and stability. In this paper,the latestresearch progress of ammonia decomposition catalysts, including catalysts based on Ru, catalysts based on non-precious metals Fe and Ni, and bimetallic catalysts, and the reaction mechanism of ammonia decompositionin recent literaturewere reviewed.

Key words: hydrogen storage, ammonia decomposition, ruthenium catalyst, non-precious metal catalysts, reaction mechanism