N-Doped NiO Nanosheet Arrays as Efficient Electrocatalysts for Hydrogen Evolution Reaction.

Exploration of cost-effective high-performance non-noble-metal-based electrocatalysts for the hydrogen evolution reaction (HER) has attracted huge attention. In this work, a nitrogen doping method is adopted to construct self-supported, N-doped NiO nanosheet arrays (N-NiO) as an effective HER electrocatalyst. The N-NiO nanosheet arrays are firmly anchored on a nickel foam substrate, forming a free-standing integrated electrode with an open nanostructure. By virtue of its larger electrochemical active surface areas and better electron conductivity, the N-NiO electrode has admirable electrocatalytic HER performance with a low overpotential (154 mV at a current density of 10 mA cm⁻²) and a low Tafel slope of 90 mV dec⁻¹. In addition, the N-NiO nanosheet arrays exhibit relatively stable electrocatalytic activity after a 10 h continuous test in an alkaline solution. Our reported rational design principle and optimization strategy provide a powerful way to construct advanced transition-metal-based electrocatalysts for the HER. [ABSTRACT FROM AUTHOR]