A Self‐Standing High‐Performance Hydrogen Evolution Electrode with Nanostructured NiCo2O4/CuS Heterostructures

An efficient self-standing 3D hydrogen evolution cathode has been developed by coating nickel cobaltite (NiCo2O4)/CuS nanowire heterostructures on a carbon fiber paper (CFP). The obtained CFP/NiCo2O4/CuS electrode shows exceptional hydrogen evolution reaction (HER) performance and excellent durability in acidic conditions. Remarkably, as an integrated 3D hydrogen-evolving cathode operating in acidic electrolytes, CFP/NiCo2O4/CuS maintains its activity more than 50 h and exhibits an onset overpotential of 31.1 mV, an exchange current density of 0.246 mA cm(-2), and a Tafel slope of 41 mV dec(-1). Compared to other non-Pt electrocatalysts reported to date, CFP/NiCo2O4/CuS exhibits the highest HER activity and can be used in HER to produce H-2 with nearly quantitative faradaic yield in acidic aqueous media with stable activity. Furthermore, by using CFP/NiCo2O4/CuS as a self-standing electrode in a water electrolyzer, a current density of 18 mA cm(-2) can be achieved at a voltage of 1.5 V which can be driven by a single-cell battery. This strategy provides an effective, durable, and non-Pt electrode for water splitting and hydrogen generation.