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

• Published in: Green energy & environment Vol. 7; no. 3; pp. 467 - 476
• Main Authors: Pei, Yuantao, Huang, Liang, Han, Lei, Zhang, Haijun, Dong, Longhao, Jia, Quanli, Zhang, Shaowei
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2022; KeAi Communications Co., Ltd
• Subjects: Catalytic activity and stability; Hierarchical NiCoP/NiOOH nanoflowers; Hydrogen evolution reaction; Ultrahigh porosity cobalt foam; Hydrogen evolution reaction; Catalytic activity and stability; Hierarchical NiCoP/NiOOH nanoflowers; Ultrahigh porosity cobalt foam
• ISSN: 2468-0257; 2468-0257
• DOI: 10.1016/j.gee.2020.10.019

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 °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 hetero-interfaces, 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. On a highly porous Co foam prepared via freeze-drying, a self-supporting hierarchical NiCoP/NiOOH electrode was in-situ fabricated and exhibited superior HER performance in alkaline media under a current density over ~500 mA cm−2. [Display omitted]