Influence of deposition conditions on performance of NiS as the bifunctional electrocatalyst in alkaline solutions by galvanostatic deposition.

The electrodeposition method is a popular synthesis method due to its low cost, simplicity, and short synthesis time. In addition, this synthesis route results in the preparation of a self-supporting electrocatalyst, which eliminates the use of binders and ultimately facilitates the durability as well as the activity of the catalyst. In this work, a series of NiS/Ni mesh electrodes are prepared by galvanostatic deposition at different deposition current densities and times. The morphology, microstructure, and elemental composition distribution of these obtained electrodes are characterized, and the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performance of the series of NiS/Ni meshes are tested. The results show that the NiS/Ni mesh electrodes electrodeposited at 30 mA cm for 1200 s have superior electrochemical performance for HER and OER. The overpotentials of NiS/Ni mesh 30 mA cm-1200 s are 236 and 244 mV for HER and OER, respectively, at a current density of 10 mA cm. In addition, the Tafel slopes for HER and OER are 113 mV dec and 176 mV dec, respectively. This research provides some valuable insights into the use of the electrodeposition method for the fabrication of electrocatalysts.