Coupling NiCo Alloy and CeO₂ to Enhance Electrocatalytic Hydrogen Evolution in Alkaline Solution

Abstract Robust and durable non‐precious metal electrocatalysts for the hydrogen evolution reaction (HER) are crucial to realize sustainable hydrogen production by electrocatalytic water splitting. In this work, a superhydrophilic NiCo nanoparticle array coupled with CeO₂ is integrated on graphite plate (NiCo–CeO₂/GP) by electrodeposition and subsequent high‐temperature selective reduction. The coupled CeO₂ can accelerate dissociation of H₂O and favor adsorption of hydrogen, prominently boosting the electrocatalytic HER activity of NiCo alloy. Also, the superhydrophilic self‐supported electrode can promote electron conduction, facilitate bubble release, and prevent catalyst shedding, ensuring an efficient and stable working condition. As a result, NiCo–CeO₂/GP exhibits an outstanding HER catalytic activity with low overpotentials of 34 mV at 10 mA cm⁻² and 140 mV at 500 mA cm⁻², as well as remarkable durability in alkaline media. Notably, this catalyst activation strategy by CeO₂ is also applicable to other Ni‐based alloys such as NiFe and NiCu, demonstrating its versatility. An alkaline electrolyzer with NiCo–CeO₂/GP as cathode and the NiCo(OH)_x–CeO₂/GP precursor electrode as anode delivers a current density of 10 mA cm⁻² at an ultralow potential (1.45 V@10 mA cm⁻²), surpassing that of the traditional Pt/C||RuO₂ electrolyzer (1.54 V@10 mA cm⁻²).