Coupling-Effect-Induced Acceleration of Electron Transfer for α-Ni(OH)₂ with Enhanced Oxygen Evolution Reaction Activity

The rational design and fabrication of nanocomposites constructed by multicomponents with synergistic functionalities are an effective approach for materials with important energy applications such as the electrocatalytic oxygen evolution reaction (OER), where there is still a challenge to obtain non-noble catalysts with high performance and practical applicability. Here, a highly active and durable OER electrocatalyst based on Ni(OH)2 nanosheets decorated by Ag nanoparticles and reduced graphene oxide (RGO) nanosheets is designed and sequentially prepared. The Ni(OH)2-Ag-RGO nanocomposite exhibits high activity as an OER electrocatalyst, achieving an overpotential of 292 mV at the current density of 10 mA cm–2 and a small Tafel slope of 58 mV dec–1 without iR-correction, and reveals a good OER property as compared with the commercial IrO2 electrocatalyst and other previously reported Ni-based OER electrocatalysts. The acceleration of electron transferring from Ni(OH)2 nanosheets to external circuit is a result of coupling effects of Ag nanoparticles and RGO nanosheets which separately serve to increase the energy of surface Ni 3d electrons and enhance the conductivity. The above mechanism is confirmed by experimental results and computational simulation. Moreover, the generality of this strategy to similar nanostructures with enhanced OER activity is demonstrated by fabricating Co(OH)2-Ag-RGO and FeOOH-Ag-RGO nanocomposites.