A Ni₂P/NiMoO nanocone electrocatalyst for efficient hydrogen evolution: tip-enhanced local electric field effect

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• The hydrogen evolution reaction (HER) in alkaline solutions suffers from sluggish kinetics, leading to high overpotentials.
• High-curvature nanostructures can enhance electrocatalytic activity via the tip-enhanced local electric field effect.

Purpose of the Study:

• To synthesize and evaluate Ni2P/NiMoO4 nanocones on nickel foam as an advanced electrocatalyst for the HER in alkaline media.
• To investigate the role of the high-curvature tips and heterostructure in enhancing HER performance.

Main Methods:

• Synthesis of Ni2P/NiMoO4 nanocones on nickel foam using a metal-organic framework template.
• Electrocatalytic testing for HER performance under alkaline conditions.
• Finite element method analysis to understand the local electric field enhancement.

Main Results:

• The Ni2P/NiMoO4 nanocone electrocatalyst exhibited low overpotentials of 49 mV at 10 mA cm-2, 137 mV at 100 mA cm-2, and 274 mV at 500 mA cm-2.
• The high-curvature tips were shown to enhance the local electric field, facilitating water dissociation and accelerating reaction kinetics.
• The electrocatalyst demonstrated excellent stability, maintaining performance over 200 hours at 300 mA cm-2.

Conclusions:

• The Ni2P/NiMoO4 nanocone heterostructure effectively enhances HER kinetics through a tip-enhanced local electric field effect and improved charge transfer.
• This work presents a viable strategy for designing efficient and stable electrocatalysts for the hydrogen evolution reaction in alkaline environments.