Enhanced oxygen evolution reaction activity of Ni(OH)2 nanosheets via the modified effect of sulfur

Abstract

Electrochemical water splitting has excellent application prospects in clean energy technology. However, due to the large overpotential required for the OER reaction during the water-splitting reaction, the modification of electrocatalysts is a vital strategy to address the slow kinetics of the OER reaction. In this paper, a simple and rapid two-step hydrothermal sulfidation method was used to prepare S-modified Ni(OH)₂ nanosheets electrocatalysts at 120 °C. At the same time, the well-designed nanostructured catalyst on the nickel foam substrate exposes a large number of active sites, and the simultaneously generated oxygen vacancies are beneficial to the penetration of the electrolyte and release of O₂, thus significantly improving the OER performance. In 1.0 M KOH electrolyte, Ni₉S₈/Ni(OH)₂/NF exhibits excellent catalytic activity for OER. The catalyst requires only 430 mV overpotential at a current density of 100 mA cm^-2. In addition, Ni₉S₈/Ni(OH)₂/NF also has excellent long-term stability.

Graphical abstract

This work reports the formation of Ni₉S₈/Ni(OH)₂/NF heterojunctions by sulfiding Ni(OH)₂ on porous nickel foam. Surprisingly, these Ni₉S₈/Ni(OH)₂/NF heterojunctions exhibit excellent oxygen evolution reaction performance and long-term stability. This is superior to most reported electrocatalysts for oxygen evolution reactions.