▎ 摘　　要

A novel ternary nanocomposite, Pd nanoparticles (NPs)/polyoxometalates (POMs)/reduced graphene oxide (rGO), was prepared by a green, mild, electrochemical-reductionassisted assembly. It is worth noting that the Keggin-type POM acts as an electrocatalyst as well as a bridging molecule. During the reduction process, POMs transfer the electrons from the electrode to GO, leading to a deep reduction of GO and the content of oxygen-containing groups is decreased to around 6.1%. Meanwhile, the strong adsorption effect between the POM clusters and rGO nanosheets induces the spontaneous assembly of POM on rGO in a uniformly dispersed state, forming a nanocomposite. The ternary Pd NPs/POMs/rGO nanocomposite exhibits higher electrocatalytic activities, better electrochemical stability, and higher resistance to CO poisoning than the Pd/C catalyst towards the formic acid oxidation (FAOR). Especially, the Pd/PW12/rGO exhibits the best electrocatalytic performance among three Pd/POMs/rGO composites (POMs = PW12, SiW12, PMo12).