An Extraordinary OER Electrocatalyst Based on the Co−Mo Synergistic 2D Pure Inorganic Porous Framework

In this paper, three Compounds have been synthesized via conventional solution method. Compound 1 is a pure 2D (two dimensional) inorganic {CoO6Mo8O28}n framework. In the structure, the rare {γ‐Mo8O28} units connect into 1D chains via vertex‐sharing mode, and further assemble into 2D frameworks by {CoO6} octahedral linkers. This Compound was proved to be a cost‐effective pre‐catalyst with excellent catalytic performances due to presence of cobalt for water oxidation with low overpotential of 293 mV at 10.0 mA cm−2 and small Tafel slope of 53 mV dec−1. Furthermore, the electrocatalytic activity can be maintained for a quite long time with the retention rate of 94 % within 24 hours. Compared with 1D {γ‐Mo8O26}n (Compound 2) and 0D {α‐Mo8O26} (Compound 3), the Co−Mo complex catalyst based on compound 1, featured with Co‐doped 2D {Mo8O28}n porous framework and Co−Mo synergistic effect, which is supported by the high resolution XPS of Co 2p and Mo 3d, exhibits an extraordinary electrocatalytic reaction for water oxidation. The work shown here enriches inorganic polyoxometalate (POM) – based functional material applied to relief energy crisis. The 2D {CoO6Mo8O28}n as a cost‐effective pre‐catalyst exhibits lower overpotential and smaller Tafel slope, demonstrating the Co−Mo synergistic effect in the electrocatalytic water oxidation.