Highly dispersed Pt-CeO2 hybrids arched on reduced graphene oxide (Pt-CeO2 /rGO) were facilely synthesized by a combination of the reverse micelle technique and a redox reaction without any additional reductant or surfactant. Under a N2 atmosphere, the redox reaction between Ce3+ and Pt2+ occurs automatically in alkaline solution, which results in the formation of Pt-CeO2 /rGO nanocomposites (NCs). The as-synthesized Pt-CeO2 /rGO NCs exhibit superior catalytic performance relative to that shown by the free Pt nanoparticles, Pt/rGO, Pt-CeO2 hybrid, and the physical mixture of Pt-CeO2 and rGO; furthermore, the nanocomposites show significantly better activity than the commercial Pt/C catalyst toward the hydrolysis of ammonia borane (NH3 BH3 ) at room temperature. Moreover, the Pt-CeO2 /rGO NCs have remarkable stability, and 92 % of their initial catalytic activity is preserved even after 10 runs. The excellent activity of the Pt-CeO2 /rGO NCs can be attributed not only to the synergistic structure but also to the electronic effects of the Pt-CeO2 /rGO NCs among Pt, CeO2 , and rGO.