▎ 摘　　要

Biological synthesis of green nanomaterials holds great promise for sustainable catalysis with versatile applications. Herein, Shewanella oneidensis MR-1 is used to develop a green method to synthesize Pd/reductive graphene oxide (rGO) nanocomposites without the addition of toxic reducing agents. It was found that S. oneidensis MR-1 cells could efficiently reduce graphene oxide to rGO and synthesize Pd nanoparticles that uniformly dispersed on the rGO nanosheets. More strikingly, the addition of GO greatly increases the recovery rate of Pd from 37.8 % to 90.4 %. After carbonization, the biosynthesized Pd/rGO nanocomposites exhibits promising catalytic activities toward oxygen reduction reaction with an onset potential of 0.92 V, a half-wave potential of 0.81 V, and a limiting current density of 5.2 mA cm(-2) in 0.1 M KOH electrolyte. This work provides a simple, "green", and cost-effective method for the preparation of graphene supported nanocomposites with extended applications.