Green and sustainable options are needed to ease the current energy and environmental crisis,and alle-viate the greenhouse effect and energy shortage.As an alternative carbon-neutral synthetic fuel,ammo-nia shows great potential due to its high energy density,non-toxic by-products,and mature related infrastructures.However,related practical applications have been severely hampered on ammonia-oxidation due to the high cost of catalysts and immature energy utilization systems.Here,we compre-hensively summarized the efforts which have been made in recent years with the aim of providing a deep sight into the development and deficiencies in this territory and trying to establish a simple framework of basic knowledge for researchers.The exploration of mechanism is discussed first and then the relevant catalysts studied in recent years are summarized.Besides,the progress of direct ammonia fuel cells(DAFCs)is also presented and the challenges as well as perspectives on future developments of electro-catalysts for ammonia electro-oxidation and its practical application are provided at the end.