Ternary Ni2(1-x)Mo2xP nanowire arrays toward efficient and stable hydrogen evolution electrocatalysis under large-current-density

Developing efficient nonprecious electrocatalysts for hydrogen evolution reaction (HER) in alkaline media at large-current-density is appealing and challenging for large-scale water electrolysis. Here, we present a theoretical and experimental study to demonstrate that ternary Ni2(1-x)Mo2xP porous nanowire arrays grown on Ni foam, as a highly efficient and stable electrocatalyst toward alkaline HER under large-current-density. Density functional theory (DFT) calculations reveal that Mo substitution of Ni in Ni2P leads to optimal free energy of water activation and hydrogen adsorption on the catalyst surface. Benefiting from the enhanced intrinsic activity, large active surface area and fast gas releasing, the Ni2(1-x)Mo2xP catalyst exhibits an excellent HER activity with low overpotentials of 72, 240, and 294 mV at current densities of 10, 500, and 1000 mA cm(-2), respectively, along with superior stability in 1 M KOH. This highly active and stable catalyst enables an electrolyzer operating at 10 mA cm(-2) at a voltage of 1.51 V, 100 mA cm(-2) at 1.65 V, and 500 mA cm(-2) at 1.82 V in 1 M KOH at room temperature, which are much better than the benchmark of IrO2/Pt. Our 3D ternary Ni2(1-x)Mo2xP catalysts significantly advance the science and technology for commercial hydrogen production.