CoHPi Nanoflakes for Enhanced Oxygen Evolution Reaction.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Efficient electrocatalysts are vital for electrochemical water splitting.
• Developing low-cost, earth-abundant electrocatalysts for the oxygen evolution reaction (OER) is a key challenge.

Purpose of the Study:

• To report a novel method for preparing two-dimensional cobalt hydrogen phosphate (CoHPi) nanoflakes.
• To investigate the OER activity and stability of the synthesized CoHPi.
• To elucidate the mechanism behind the enhanced catalytic performance.

Main Methods:

• Chemical conversion of α-Co(OH)₂ precursor at room temperature.
• Synthesis of 2D CoHPi nanoflakes with a thickness of 3 nm.
• Electrochemical characterization including OER activity and stability tests.
• Mechanism studies involving analysis of active sites, hydrophilicity, and mass transfer.

Main Results:

• Successfully synthesized ultrathin 2D CoHPi nanoflakes.
• CoHPi exhibits enhanced OER activity and excellent stability.
• The HPO₄^2- anions in CoHPi facilitate the proton-coupled electron-transfer (PCET) process.
• Performance enhancement is attributed to abundant active sites, superhydrophilicity, and efficient mass/charge transfer.

Conclusions:

• The novel 2D CoHPi nanoflakes are promising electrocatalysts for OER.
• The ultrathin structure and anion-mediated PCET contribute to superior catalytic performance.
• This work offers a new pathway for designing efficient and stable OER electrocatalysts.