Ce-Doped Ni–S nanosheets on Ni foam supported NiMoO4 micropillars: fast electrodeposition, improved electrocatalytic activity and ultralong durability for the oxygen evolution reaction in various electrolytes

Abstract

Developing active, durable, and inexpensive electrocatalysts for the oxygen evolution reaction (OER) is drawing increased interest. Here, a mild hydrothermal–electrodeposition two-step route is designed for the preparation of Ce-doped Ni–S@NiMoO₄ micropillar composites on nickel foam (CeNiS@NiMoO₄/NF). The as-constructed CeNiS@NiMoO₄/NF electrode shows an ultralow overpotential, fast kinetics, superb intrinsic activity and excellent long-term stability for the OER. In 1 M KOH solution, 187 mV overpotential is required to deliver a current density of 10 mA cm⁻² with a Tafel slope of 35.28 mV dec⁻¹, and in a saline-alkaline solution of 1 M KOH and 0.5 M NaCl, only 260 mV overpotential is needed to reach 100 mA cm⁻², demonstrating its excellent OER performance. The above outstanding electrocatalytic activity is attributed to the influence of CeNiS nanosheets on the surface microstructure of NiMoO₄ micropillars, which not only improves the conductivity of the catalyst, but also increases the surface area, as well as accelerates the escape of gases produced. Compared with other non-precious metal OER electrocatalysts, the as-prepared CeNiS@NiMoO₄/NF presents stronger or close electrocatalytic activity and better durability, which provides a new electrocatalyst selection in practical applications.