Engineering Metallic Alloy Electrode for Robust and Active Water Electrocatalysis with Large Current Density...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing efficient electrocatalysts for the oxygen evolution reaction (OER) is crucial for cost-effective electrochemical hydrogen production.
• Current catalysts often suffer from kinetic sluggishness and instability, hindering large-scale industrial hydrogen (H2) generation.

Purpose of the Study:

• To enhance the intrinsic activity and stability of Ni1-x Fex nanochain arrays for OER.
• To enable robust water splitting at extremely large current densities for industrial hydrogen production.

Main Methods:

• Introducing a trace proportion of heteroatom phosphorus doping into Ni1-x Fex nanochain arrays.
• In situ characterization to understand the formation of Ni2P and Ni5P4 species on the electrode surface.
• Electrochemical testing at high current densities (1000 and 2000 mA cm-2) for extended periods (760 h).

Main Results:

• Achieved robust water splitting at 1000 and 2000 mA cm-2 for 760 hours with phosphorus-doped Ni1-x Fex nanochain arrays.
• Demonstrated exceptionally low overpotentials: 222 mV at 10 mA cm-2 and 327 mV at 2000 mA cm-2.
• The alkaline electrolyzer operated at a low voltage of 1.75 V at 1000 mA cm-2, outperforming benchmark IrO2.

Conclusions:

• Heteroatom phosphorus doping significantly enhances the OER activity and stability of Ni1-x Fex nanochain arrays.
• The hierarchical electrode geometry and in situ formed Ni2P/Ni5P4 species promote reaction kinetics.
• This work represents vital progress toward large-scale, cost-efficient hydrogen production via industrial water electrolysis.