Surface engineered CoP/Co₃O₄ heterojunction for high-performance bi-functional water splitting electro-catalysis

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrochemical water splitting integrates hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) for energy efficiency.
• Existing catalysts face challenges with stability in acidic media (OER) or poor kinetics in alkaline media (HER).

Purpose of the Study:

• To develop a bifunctional catalyst for efficient electrochemical water splitting in alkaline environments.
• To address the limitations of current catalysts in terms of stability and kinetics.

Main Methods:

• Fabrication of a CoP/Co3O4 heterostructure.
• Surface engineering to introduce oxygen (O) and phosphorus (P) defects, creating s-CoP/Co3O4.
• Evaluation of the catalyst's performance in alkaline HER and OER.

Main Results:

• The s-CoP/Co3O4 catalyst achieved a current density of -10 mA cm-2 at an overpotential of 106 mV vs. RHE for alkaline HER.
• For OER, the catalyst required an overpotential of 211 mV vs. RHE at 10 mA cm-2 with a low Tafel slope of 58.4 mV dec-1.
• Demonstrated bifunctional catalytic activity in 1 M KOH.

Conclusions:

• The developed s-CoP/Co3O4 heterostructure serves as an effective bifunctional catalyst for alkaline water splitting.
• Surface engineering creating unsaturated metal sites offers a low-cost approach to enhance electro-catalytic activity.
• This work presents a promising strategy for scalable and cost-effective hydrogen production.