▎ 摘　　要

Well dispersed magnetically recyclable bimetallic CoNi nanoparticles (NPs) supported on the reduced graphene oxide (RGO) were synthesized by one-step in situ coreduction of aqueous solution of cobalt(II) chloride, nickel (II) chloride, and graphite oxide (GO) with ammonia borane (AB) as the reducing agent under ambient condition. The CoNi/RGONPs exhibits excellent catalytic activity with a total turnover frequency (TOF) value of 19.54 mol H-2 mol catalyst(-1) min(-1) and a low activation energy value of 39.89 kJ mol(-1) at room temperature. Additionally, the RGO supported CoNi NPs exhibit much higher catalytic activity than themonometallic and RGO-free CoNi counter parts. Moreover, the as-prepared catalysts exert satisfying durable stability and magnetically recyclability for the hydrolytic dehydrogenation of AB, which make the practical reusing application of the catalystsmore convenient. The usage of the low-cost, easy-getting catalyst to realize the production of hydrogen under mild condition gives more confidence for the application of ammonia borane as a hydrogen storage material. Hence, this general method indicates that AB can be used as both a potential hydrogen storage material and an efficient reducing agent, and can be easily extended to facile preparation of other RGO-based metallic systems.