Study of the influence of different anionic electrolytes on the water electrolysis performance of Ni3S2 based materials

It is critical to explore robust catalysts and research the catalyst's response to specific anions in alkaline seawater. In this paper, Ni3S2-based electrodes were in situ generated on nickel foam (NF) through hydrothermal preparation method to produce Ni3Sn2S2@Ni3S2/NF, FeS@Ni3S2/NF and Ni3S2/NF. Compared with other catalysts, Ni3Sn2S2@Ni3S2/NF has superior activity in hydrogen evolution reactions (HER) in the studied electrolyte systems, especially containing chloride ions. When the electrolyte conditions were 1 M KOH +1 M NaCl and 1 M KOH + seawater, the Ni3Sn2S2@Ni3S2/NF catalyst could reach the 10 mA cm−2 at the small overpotential of 116 mV and 117 mV. However, the oxygen evolution reactions (OER) performance of Ni3Sn2S2@Ni3S2/NF catalyst is excellent in the chlorine-containing electrolyte, but decreased in the non-chlorine-containing electrolyte. The results show that chloride ions may have a positive influence on the electrolytic process of the electrode. It is worth mentioning that the unique cubic nanostructure of Ni3Sn2S2@Ni3S2/NF provided a lot of reactive centres, and after 12 h full hydrolysis measurement in 1 M KOH + seawater condition, a lot of tiny nanocube structures were added on the surface of Ni3Sn2S2@Ni3S2/NF. Therefore, Ni3Sn2S2@Ni3S2/NF is a high performance catalyst with promising applications in alkaline electrolyte containing chloride ions.