▎ 摘　　要

Here, two new polyoxometalate (POM)-based biimidazole (H(2)biim) complexes formulated as [Ag(H(2)biim)(2)](2)[Ag-4(H(2)biim)(4)][(PW12O40)(2)] (1) and [Ag(H(3)biim)(2)][PW12O40]center dot 4H(2)O (2) were synthesized by a hydrothermal method, and their structures were determined by single-crystal X-ray diffraction and other physico-chemical and spectroscopic methods. Furthermore, by using 1 and 2 as precursors, graphene as a carrier and N,N-dimethylformamide (DMF) as a reducing agent, two kinds of POM and Ag nanoparticle with high dispersion loaded graphene composite materials (denoted as PW12/Ag/graphene-a and PW12/Ag/graphene-b, respectively) were prepared through a one-step synthesis method. PW12/Ag/graphene-a and PW12/Ag/graphene-b were applied in electrocatalytic water oxidation in neutral media and obtained lower overpotentials than the reference electrodes including Ag/graphene, PW12/graphene, and PW12/Ag/graphene owing to a synergistic role of the three components. The composite electrodes display good stability. This work provides new insight for preparing water oxidation catalysts using Ag-based POMs as precursors.