NiCoP/NiOOH nanoflowers loaded on ultrahigh porosity Co foam for hydrogen evolution reaction under large current density

Developing user-friendly electrodes for efficiently producing hydrogen from water to substitute non-renewable fossil fuels is one of the challenges in the hydrogen energy field. For the first time, we have prepared self-supporting ultrahigh porosity cobalt foam loaded with NiCoP/ NiOOH nanoflowers (NiCoP/CF) via freeze-drying and phosphorization. The as-prepared hierarchical NiCoP/CF electrodes showed superior catalytic activity for hydrogen evolution reaction (HER) in alkaline media. The one resulted from phosphorization at 350 degrees C (NiCoP/CF-350) only required overpotential of -47, and -126 mV to deliver geometrical current density of -10 mA cm(-2) and -100 mA cm(-2), respectively, demonstrating improved catalytic activity than the electrodes prepared using a commercial nickel foam as a support. Moreover, it could retain its superior stability at a current density higher than -500 mA cm(-2) for 16 h. Such an outstanding performance can be attributed to the ultrahigh porosity of Co foam support, optimal adsorption energies of HER intermediates (H*), facile water dissociation on the NiCoP/NiOOH heterointerfaces, and the assistance of NiOOH facilitating the electrons transfer from the Co foam inside to the NiCoP outside. The work would provide a new strategy for future design of advanced HER electrocatalysts. (C) 2020 Institute of Process Engineering, Chinese Academy of Sciences. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co., Ltd.