CuS–Ni3S2 grown in situ from three-dimensional porous bimetallic foam for efficient oxygen evolution

Abstract

The development of efficient and stable electrocatalysts for the oxygen evolution reaction (OER), which is critical for the development of water splitting, has attracted great interest from many researchers. However, there have been few reports exhibiting satisfactory activity and durability under high current density (up to 1000 mA cm⁻²), which are significant for the practical production of water splitting. Herein, a novel electrocatalyst, CuS–Ni₃S₂, in situ grown from porous CuNi alloy supported on nickel foam (CuS–Ni₃S₂/CuNi/NF) was obtained via a facile two-step method, and it has achieved excellent OER performance in alkaline solution even under high current density. The electrocatalyst only needed low overpotentials of 337, 444 and 510 mV to reach the very high current densities of 100, 500, and 1000 mA cm⁻², respectively, and it presented excellent durability at a relatively high current density of 100 mA cm⁻² for 15 h. Despite the current density being normalized by the catalytic electrode's geometrical area, both the mass activity and turnover frequency (TOF) for each active site showed the superior catalytic activity of CuS–Ni₃S₂/CuNi/NF. With the assistance of theoretical calculations, the participation of CuS was demonstrated to contribute to the excellent OER performance, providing a promising composition for designing and synthesizing novel OER catalysts.