▎ 摘　　要

Severe aggregation of reduced graphene oxide nanosheets and their weak adhesion to the conductive substrate largely restricts the electrocatalytic property. To overcome this flaw, we propose a simple strategy for fabrication of efficient reduced graphene oxide film through in-situ thermal conversion of graphene oxide film that is first adsorbed onto the conductive substrate. As compared to the reduced graphene oxide film prepared from the direct adsorption of reduced graphene oxide nanosheets, the reduced graphene oxide film obtained from the in-situ thermal conversion of graphene oxide film exhibits much higher electrocatalytic activity on the reduction of I-3(-) due to the stronger adhesion to the conductive substrate and better film quality without aggregation. The thermal-converted reduced graphene oxide cathode produces much higher power conversion efficiency (6.35%) than that (1.20%) for the directly adsorbed reduced graphene oxide cathode. This work opens up a new avenue for preparation of simple and low-cost cathodes.