Hierarchical NiCoP/NiCo architecture on Ni mesh boosts hydrogen production under industrial alkaline conditions

Industrial alkaline water electrolysis (AWE) has been burdened with huge energy consumption due to the large overpotential and poor stability of electrocatalysts for hydrogen evolution reaction (HER). Herein, we develop a hierarchical NiCoP/NiCo catalyst on Ni mesh (NCP/NC/Ni) via a facile electrodeposition method, which exhibits a remarkable HER performance under laboratory conditions with a small overpotential of 237 mV to yield -500 mA cm-2 for 30 days. When pairing with a Ni mesh anode in an AWE device under industrial conditions (30 wt% KOH, 85 degrees C), the NCP/NC/Ni||Ni electrolyzer can give a steady current density of 500 mA cm-2 at 1.88 V for 30 days, overmatching that of the industrial-used Raney Ni/Ni||Ni (2.05 V). Systemic experiments and theoretical calculations elucidate that the outstanding HER performance is originated from the excellent intrinsic HER activity of the amorphous NCP and the multifunctional roles of the NC buffer layer. The micro-cones textured NC layer provides abundant active sites and promotes the mass transfer of H2-bubbles and charge transfer due to the improvement of the electrical contact between NCP and Ni. More impressively, NC also releases the stress between Ni and NCP, making the disappearance of the cracks on the dense NCP layer and improving the lifetime of the catalyst. This work gives an avenue to develop highly efficient and stable catalytic materials for industrial AWE through designing a hierarchical architecture.