Electronic Structure Evolution in Tricomponent Metal Phosphides with Reduced Activation Energy for Efficient...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Efficient electrocatalytic oxygen evolution reaction (OER) is crucial for water splitting technologies.
• Non-noble metal catalysts are sought as cost-effective alternatives to precious metals for large-scale applications.

Purpose of the Study:

• To synthesize novel tricomponent metal phosphides with hollow structures for enhanced OER performance.
• To investigate the role of Ni and Fe incorporation in tuning the electronic structure and catalytic activity.

Main Methods:

• Synthesis of hollow tricomponent metal phosphides from cobalt-contained metal-organic frameworks (MOFs, ZIF-67) via tailored Ni and Fe ratios.
• High-temperature reduction and subsequent phosphidation process.
• Electrochemical characterization in 1 m NaOH aqueous solution.

Main Results:

• Achieved excellent OER activity with an overpotential of 329 mV at 10 mA cm⁻² and a Tafel slope of 48.2 mV dec⁻¹.
• Demonstrated long-time stability, outperforming noble metal-based catalysts.
• Identified in situ formed (oxyhydr)oxide/phosphate species as the active sites responsible for OER.

Conclusions:

• Simultaneous introduction of Ni and Fe elements significantly modifies the electronic structure of metal phosphides, enhancing OER performance.
• The strategy of using MOFs as precursors and tuning electronic structures offers a versatile approach for developing high-efficiency water splitting electrocatalysts.