Constructing Ag modified NiCoSe2 hybrid nanosheet on 3D-nickel foam as a robust oxygen evolution reaction electrocatalyst

Transition metal selenides are promising oxygen evolution reaction (OER) catalysts, and element doping is a strategy to further enhance their catalytic performance. However, the choice of doping elements and methods needs further study. In this work for cobalt selenide, Ni is has been selected for isomorphic doping to NiCoSe₂ with silver doped in bulk to obtain Ag–NiCoSe₂ nanosheet on NF. The addition of nickel can form a eutectic phase with cobalt to obtain an effective synergistic catalytic effect. The addition of Ag can regulate the adsorption energy of the active site and conductivity. The as-prepared Ag–NiCoSe₂/NF has good catalytic performance for OER, and a current density of 100 mA cm^?2 can be achieved with only 270 mV. Its catalytic ability is far superior to that of non-Ag-doped NiCoSe₂, which is due to the fact that the sheet structure provides more active sites, and the metal doping modulates the electronic configuration, which effectively improves the intrinsic activity. Moreover, Ag–NiCoSe₂/NF can maintain a long-term high-efficiency catalytic process for more than 20 h at a current density of 100 mA cm^?2. Therefore, this work proves that metal doping is of great significance for improving the catalytic activity of transition metal selenides.