▎ 摘　　要

A series of PtxCo1-x bimetallic nanoparticles (NPs) were deposited on polyethyleneimine (PEI) decorated graphene oxide (GO) by a simple co-reduction method. The PEI molecules facilitated the uniform distribution of bimetallic NPs (similar to 2.3 nm) on GO. PEI-GO/Pt0.17Co0.83 showed extraordinary catalytic properties: a total turnover frequency of 377.83 mol(H2) min(-1) mol(metal)(-1), a hydrogen generation rate of 111.28 L-H2 min(-1) g(metal)(-1) at 298 K, an activation energy of 51.6 kJ mol(-1) and good recyclability (similar to 80% of the original activity after five cycles). The synergistic effect between Pt and Co, and the small size of these NPs play important roles in improving their catalytic properties. Such low-cost, recyclable bimetallic catalysts will enable many practical applications in portable devices and fuel cells.