Edge-Selected Selenization of Subnanometer Amorphous NiFe Hydroxides for Efficient Alkaline Oxygen Evolution

Area of Science:

• Materials Science
• Catalysis
• Electrochemistry

Background:

• Crystalline-amorphous (c-a) heterointerfaces are key for advanced nanomaterials in catalysis.
• Precise control over subnanometer c-a interfaces for maximizing catalytic sites is challenging.

Purpose of the Study:

• To engineer a hierarchical c-a heterostructure on subnanometer NiFe hydroxide.
• To enhance oxygen evolution reaction (OER) performance through atomic-scale structural refinement and interfacial optimization.

Main Methods:

• Dual ligand-assisted synthesis strategy.
• Selective selenization of amorphous materials to create crystalline Ni_0.85Se@amorphous NiFe hydroxide.
• Spectroscopic techniques and theoretical calculations.

Main Results:

• Achieved exceptional OER activity with an ultralow overpotential (225 mV at 10 mA cm^-2).
• Demonstrated superior performance in anion exchange membrane water electrolyzers (1.78 V at 1.0 A cm^-2).
• Identified that the Ni_0.85Se layer modulates active sites, enhances charge transfer, and optimizes intermediate adsorption.

Conclusions:

• Established a universal blueprint for designing high-performance c-a heterocatalysts.
• Synergized atomic-level design with interfacial engineering for energy conversion.
• Highlighted the potential of engineered c-a heterostructures for water electrolysis.