Defect-rich engineering and F dopant Co-modulated NiO hollow dendritic skeleton as a self-supported electrode for high-current density hydrogen evolution reaction

Exploring the low-cost and high-efficient electrocatalysts with Pt-like activity for alkaline hydrogen evolution through water splitting is imperative yet challenging. Herein, a simple synthesis combined with electrodeposition and facile electro-oxidation is developed to construct the hollow dendritic self-supported electrode (HDSE). X-ray photoelectron spectroscopy (XPS), X-ray absorption fine structure (XAFS), and electron paramagnetic resonance (EPR) reveal that the surface of HDSE contains the abundant NiO, which is further decorated by fluorine (F)-doped and oxygen vacancies after electro-oxidation process. The resultant HDSE achieves an excellent electrocatalytic performance for hydrogen evolution reaction (HER) in alkaline condition, leading to the extremely low overpotential of 13 mV to drive a current density of −10 mA·cm⁻², and exhibits the long-time stability at the current density of −100 mA·cm⁻² and −500 mA·cm⁻², which is superior to the electrocatalytic ability of Pt/C. Density functional theory (DFT) calculations illustrate the NiO modulated by F-doping and oxygen vacancy, could synergistically improve the charge distribution, enhance the conductivity of NiO structure, and optimize the adsorption energy for intermediates of HER, thus accelerating the electrocatalytic ability for hydrogen evolution. This work opens up a new avenue toward the reasonable design of high-efficient and low-cost electrocatalysts for alkaline hydrogen evolution reaction.