Synergistic Activation of Crystalline Ni2P and Amorphous NiMoO x for Efficient Water Splitting at High Current Densities

Theoverpotential of alkaline water electrolysis at high currentdensity is significantly increased by the high energy barriers ofhigh intermediate (H* and OH*) and slow mass/charge transfer. Modifyingthe electronic structure and morphology of catalysts to decrease energybarriers and enhance mass/charge transfer is a promising approach,but it presents significant challenges. In this study, the crystallineNi(2)P clusters were coupled with an amorphous NiMoO x nanorod support on a nickel foam substrate(Ni2P-NiMoO x /NF) tocreate a heterojunction that enhances mass/charge transfer, tunesenergy barriers, and improves reaction kinetics through synergisticactivation. The Ni2P-NiMoO x /NF exhibits ultralow overpotentials of 91, 188, and 297 mVat 10, 100, and 500 mA cm(-2), respectively, for thehydrogen evolution reaction, along with stability. It also shows superiorperformance in the oxygen evolution reaction. Remarkably, the Ni2P-NiMoO x /NF-based electrolyzerachieves 100 and 400 mA cm(-2) at low cell voltagesof 1.66 and 2.08 V, respectively, while also maintaining stable electrolysisfor 100 h under industrial testing (65 & DEG;C with 30% KOH). Additionalcharacterization and density functional theory calculations demonstratethat the interaction between Ni2P and NiMoO x facilitates the downshifting of d-band centers tothe Fermi level, which results in the activation of the local electronicstructure, promoting H2O dissociation and enhancing theoverall catalytic activity.