Reconstructed Hydroxyl Coordination Field Enhances Mass Transfer for Efficient Electrocatalytic Water Oxidation

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Mass transfer is critical for accelerating oxygen evolution reaction (OER) at high current densities.
• Limited research exists on effectively modulating reactant mass transport in OER catalysts.
• Layered double hydroxides (LDHs) are promising OER electrocatalysts, but their mass transport limitations need addressing.

Purpose of the Study:

• To enhance mass transport in layered double hydroxides (LDHs) for improved oxygen evolution reaction (OER) performance.
• To investigate the role of an interlayer hydroxide coordination field (IHCF) in facilitating reactant mass transport.
• To demonstrate the potential of IHCF for designing highly efficient and stable water oxidation catalysts.

Main Methods:

• In situ electrochemical reconstruction of LDHs to activate electronic properties and form an IHCF.
• Utilizing dual acid-base properties of aluminum sites for catalyst modification.
• Employing deuterium kinetic isotope effect and pH-dependence measurements to study reaction mechanisms.
• Conducting long-term stability tests in an alkaline flow electrolyzer.

Main Results:

• Electrochemical reconstruction successfully created an IHCF in LDHs, enhancing electronic activity and mass transport.
• The IHCF significantly improved reactant mass transport, leading to a low overpotential of 164 mV for OER.
• Kinetic isotope and pH studies confirmed enhanced substrate mass transport and structural stability due to IHCF.
• Catalysts demonstrated over 1000 hours of stability at high current density in flow electrolyzer tests.

Conclusions:

• The interlayer hydroxide coordination field (IHCF) effect is a powerful strategy to enhance mass transport in OER catalysts.
• This approach offers a new avenue for designing efficient and stable water oxidation electrocatalysts for practical applications.
• The findings highlight the importance of mass transport modulation in advancing electrocatalytic processes.