Monolithic Ni‐Mo‐B Bifunctional Electrode for Large Current Water Splitting

Abstract Screening and developing highly efficient electrodes is key to large‐scale water electrolysis. The practical industrial electrode should fulfill several criteria of high activity, structural stability, and fast bubble evolution at a large current density. In this study, a novel monolithic 3D hollow foam electrode that can achieve the requirements of large current density water electrolysis is developed and fabricated through a simple electroless plating‐calcination strategy. This strong 3D Ni‐Mo‐B hollow foam electrode can withstand a pressure of 2.37 MPa and exhibits high electrochemical surface area, high conductivity, and low gas transfer resistance, drastically boosting its catalytic performance. It affords 50 mA cm –2 at overpotentials of only 68 mV for hydrogen evolution reaction and 293 mV for oxygen evolution reaction and can survive at a large current density of 5 A cm –2 while maintaining its structure and performance in 1.0 m KOH. The advantages of facile preparation, high mechanical strength, high gas mass transfer ability, and excellent performance enable this structure to be a potential electrode, active substrate, or 3D catalyst in many fields.