Modulating the covalency of Ru-O bonds by dynamic reconstruction for efficient acidic oxygen evolution

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Stable oxygen evolution reaction (OER) catalysts are crucial for acidic conditions.
• Suppressing lattice oxygen participation is vital for catalyst longevity.
• Ruthenium-based oxides are promising but face stability challenges.

Purpose of the Study:

• To develop a ruthenium-based oxide catalyst that prevents lattice oxygen involvement during OER.
• To enhance the stability and efficiency of OER catalysts under acidic conditions.
• To investigate the dynamic optimization of RuO2 during the reaction process.

Main Methods:

• Construction of a RuO2 nanoparticle-anchored LiCoO2 nanosheet electrocatalyst (RuO2/LiCoO2).
• Electrochemical delithiation of the LiCoO2 support to tune Ru-O bond covalency.
• Performance evaluation in 0.5 M H2SO4 and proton exchange membrane water electrolysis.

Main Results:

• The RuO2/LiCoO2 catalyst demonstrated dynamic RuO2 optimization during OER.
• Weakened Ru-O covalent bonds inhibited lattice oxygen participation, ensuring active site stability.
• Extended Ru-O bonds reduced the *OOH intermediate formation energy barrier, accelerating OER.
• Achieved an overpotential of 150 ± 2 mV at 10 mA cm-2 in 0.5 M H2SO4.
• Exhibited stable operation for 2000 h at 1 A cm-2 in proton exchange membrane water electrolysis.

Conclusions:

• The RuO2/LiCoO2 catalyst offers superior stability and efficiency for acidic OER.
• Electrochemical delithiation provides a method for dynamic catalyst optimization.
• This approach opens new avenues for designing robust ruthenium-based OER catalysts.