Water Oxidation at Neutral pH using a Highly Active Copper-Based Electrocatalyst.

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Sluggish oxygen evolution reaction (OER) kinetics hinder efficient hydrogen production in water splitting.
• Copper catalysts show promise for OER in basic conditions, but acidic/neutral OER remains challenging.
• Developing efficient catalysts for neutral pH water oxidation is critical for easier hydrogen evolution.

Purpose of the Study:

• To present an efficient and robust copper-based molecular catalyst for OER under neutral conditions.
• To investigate the self-assembly mechanism and catalytic performance of the copper film.
• To elucidate the active sites and reaction mechanism using experimental and computational methods.

Main Methods:

• Self-assembly of a copper-based molecular catalyst film on a glassy carbon electrode.
• Controlled potential electrolysis to assess catalytic current and stability.
• Electrochemical techniques and Density Functional Theory (DFT) calculations to study the reaction mechanism.

Main Results:

• The self-assembled copper film catalyzes OER under neutral conditions with a low overpotential.
• A stable catalytic current of 1.0 mA cm⁻² is achieved at 2.0 V (vs. RHE) with no significant degradation after prolonged electrolysis.
• DFT calculations identified Cu(I) sites within the film as active centers for OER, with a calculated overpotential of 0.31 V.

Conclusions:

• The developed Cu-based molecular catalyst film is efficient and robust for OER under neutral conditions.
• The catalyst exhibits first-order kinetics and a single-site mechanism with a turnover frequency (TOF) of 0.6 s⁻¹.
• The study provides insights into defect-mediated catalysis for efficient water oxidation, paving the way for improved hydrogen production technologies.