Gold-Doped Cobalt–Nickel Sulfide Nanosheets for Oxygen Evolution Reaction

The electrolytic water of oxygen evolution reaction is a four-electron transport process, which results in a slow kinetic process coupled with a high oxygen evolution reaction application potential; therefore, the catalysts have become an urgent bottleneck in the research of hydrolysis reactions. Research on the oxygen evolution reaction is booming with various materials such as noble metals and transition metals. Because of their intrinsically excellent charge transport properties and cost-effective features, transition metal sulfides have attracted much investigation. Herein, we combined the synergistic catalysis of transition metals with the modification of trace noble metal atoms to design and synthesize gold-doped cobalt–nickel sulfide nanosheets (Au-CoNiS x NSs) for oxygen evolution reaction. The cobalt–nickel ratio of electrodeposition and the doping of Au on the millimolar scale were studied. The doping of Au atoms promoted the deposition of sulfur elements and led to the formation of more compact nanostructures, thereby improving the OER performance. The optimal electrochemical performance was obtained with Co/Ni = 3:1 and Au addition of 0.5 mmol/L, with an overpotential of 305.9 mV (vs RHE) at a current density of 10 mA/cm 2 and a Tafel slope of 60.98 mV/dec. In the chronopotentiometry measurement, there was no significant difference in electrochemical performance within 12 h, indicating that the nanomaterial has good catalytic stability.