CoMn phosphide encapsulated in nitrogen-doped graphene for electrocatalytic hydrogen evolution over a broad pH range

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing efficient electrocatalysts for hydrogen evolution reaction (HER) is crucial for clean energy technologies.
• Existing catalysts often suffer from limited stability or activity across varying pH conditions.
• Novel materials with enhanced catalytic properties are needed to overcome these limitations.

Purpose of the Study:

• To synthesize and characterize a novel CoMn phosphide encapsulated in a nitrogen-doped graphene core-shell structure.
• To evaluate the catalytic performance of this heterostructure for hydrogen evolution reaction (HER) across a broad pH range.
• To assess the stability and durability of the synthesized catalyst.

Main Methods:

• Synthesis of CoMn phosphide using Prussian Blue complexes as precursors.
• High-temperature doping with phosphorus atoms.
• Encapsulation within a nitrogen-doped graphene core-shell structure.
• Electrochemical characterization of hydrogen evolution reaction (HER) activity and stability at different pH values (0, 7, and 14).

Main Results:

• Successful preparation of CoMn phosphide encapsulated in a nitrogen-doped graphene core-shell heterostructure.
• Achieved low overpotentials for HER: 159 mV at pH 0, 190 mV at pH 14, and 279 mV at pH 7 at a current density of 20 mA cm⁻².
• Demonstrated excellent catalytic stability over extended operation periods.
• The nitrogen-doped graphene shell provided enhanced conductivity and structural integrity.

Conclusions:

• The developed CoMn phosphide/nitrogen-doped graphene core-shell catalyst exhibits superior HER performance.
• The catalyst's effectiveness across a wide pH range makes it a promising candidate for various electrochemical applications.
• The unique core-shell structure contributes significantly to the catalyst's activity and stability.