Developing a Cobalt Phosphide Catalyst with Combined Cobalt Defects and Phosphorus Vacancies to Boost Oxygen...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Defect engineering is crucial for enhancing catalyst performance.
• Optimizing surface charge and active sites of cobalt phosphide (CoP) catalysts improves oxygen evolution reaction (OER) efficiency.

Purpose of the Study:

• To develop a novel Co1-xPv catalyst with coexisting cobalt defects and phosphorus vacancies.
• To evaluate the catalyst's performance in oxygen evolution reaction (OER) and electrocatalytic water splitting (EWS).

Main Methods:

• Synthesis of a Co1-xPv catalyst featuring both cobalt and phosphorus vacancies.
• Electrochemical testing of the catalyst in basic and acidic media for OER.
• Performance evaluation in alkaline electrocatalytic water splitting (EWS) using a Co1-xPv || Pt/C cell.

Main Results:

• The Co1-xPv catalyst demonstrated modest overpotentials of 238 mV (basic) and 249 mV (acidic) at 10 mA cm-2 for OER.
• In alkaline EWS, the Co1-xPv || Pt/C cell operated at a low voltage of 1.51 V, outperforming RuO2 || Pt/C (1.66 V).
• Enhanced catalytic efficiency and longevity were attributed to a tunable electronic structure, facilitated Co2+ to Co3+ transformation, and improved oxygen species interaction.

Conclusions:

• Coexisting cobalt and phosphorus vacancies in CoP catalysts significantly enhance OER efficiency.
• The developed Co1-xPv catalyst offers a promising alternative to noble metal catalysts for water splitting.
• This defect engineering strategy provides a new pathway for designing advanced transition metal phosphide catalysts for energy conversion.