Ni-B-P micro spheres for superior water splitting OER electrocatalyst satisfying industrial operational requirement

To satisfy the global energy demands and deal with the climate crisis, it is necessary to develop an advanced alternative electrocatalyst for hydrogen generation by water electrolysis, which meets the industrial operational requirements. Herein, the nickel-boride-phosphide (Ni-B-P) micro spheres are fabricated by a hydrothermal approach and significantly improved OER/HER catalytic activities are demonstrated through optimizations of various synthesis parameters. The Ni-B-P sphere electrode demonstrates significantly higher OER performance over the RuO2 benchmark electrode due to the improved charge transfer capacity and large ECSA with the micro spherical morphology and excellent stability and corrosion resistance. The Ni-B-P micro spheres demonstrate the OER overpotential of 360 mV at 300 mA/cm2 as compared to 460 mV of RuO2 benchmark. The bifunctional Ni-B-P sphere electrode readily reaches the high current of 2,000 mA/cm2 with 3.62 and 3.42 V in 1 M and 6 M KOH and demonstrates excellent durability for over 5 days (120-hr) of continuous operation at the high alkaline concentration at elevated temperature, meeting the industrial operation requirement. In addition, coupling with Pt/C (Pt/C ‖ Ni-B-P), the hybrid configuration demonstrates super-low cell voltages of 2.89 and 2.72 V at 2,000 mA/cm2 in 1 M and 6 M KOH with the superior stability, indicating the feasibility of commercial OER application.