Beyond Platinum: Defects Abundant CoP₃/Ni₂P Heterostructure for Hydrogen Evolution Electrocatalysis

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Water electrolysis offers a pathway for pure hydrogen production but is hindered by high costs.
• Developing cost-effective electrocatalysts for the hydrogen evolution reaction (HER) is crucial for economic viability.
• While heterostructures show promise for HER, their activity often trails behind commercial platinum-based catalysts (Pt/C).

Purpose of the Study:

• To engineer vacancy-type defects at the interface of cobalt phosphide/nickel phosphide (CoP3/Ni2P) heterostructures.
• To investigate the impact of these defects on the hydrogen evolution reaction (HER) activity.
• To develop a low-cost, high-performance electrocatalyst for efficient water splitting.

Main Methods:

• Plasma strategy employed to introduce vacancy defects into the CoP3/Ni2P heterostructure interface.
• Electrocatalytic performance evaluation for HER in acidic and alkaline media.
• Assessment of catalytic activity and current density for water electrocatalysis.
• Theoretical calculations (e.g., DFT) to elucidate the mechanism of defect-induced enhancement.

Main Results:

• The synthesized defective CoP3/Ni2P exhibited lower overpotentials compared to commercial Pt/C.
• Specific activity at 50 mV overpotential was approximately 2-fold higher in acidic and 1.7-fold higher in alkaline media than Pt/C.
• Achieved a current density of 215 mA cm⁻² at 2.0 V for water electrocatalysis, meeting industrial standards.
• Theoretical calculations confirmed that interfacial defects optimize electronic structure, accelerate charge transfer, and lower energy barriers for water dissociation.

Conclusions:

• Introducing vacancy defects into CoP3/Ni2P heterostructures is an effective strategy to enhance HER performance.
• The defective CoP3/Ni2P catalyst demonstrates superior activity and stability over Pt/C in both acidic and alkaline environments.
• This work presents a promising low-cost electrocatalyst for practical industrial water splitting and efficient hydrogen production.