Regulating Surface Charge by Embedding Ru Nanoparticles over 2D Hydroxides toward Water Oxidation.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing efficient electrocatalysts for the oxygen evolution reaction (OER) is crucial for green hydrogen production.
• Earth-abundant and highly active catalysts are sought after to reduce costs and improve sustainability.

Purpose of the Study:

• To explore microwave-assisted decoration of ruthenium nanoparticles (Ru NPs) on bimetallic layered double hydroxide (LDH) as an OER electrocatalyst.
• To investigate the effect of Ru NP loading on OER activity and understand the underlying catalytic mechanisms.

Main Methods:

• Synthesis of Ru NPs decorated CoFe-LDH using microwave-assisted methods.
• Electrochemical characterization of the catalyst for OER in 1 M KOH.
• In situ impedance spectroscopy and Density Functional Theory (DFT) calculations.

Main Results:

• Optimized Ru@CoFe-LDH(3%) achieved an overpotential of 249 mV at 10 mA/cm² with a TOF of 14.4 s⁻¹.
• A concentration-dependent volcanic relationship was observed between electronic charge and thermoneutral current densities, indicating adherence to the Sabatier principle.
• Ru NP incorporation boosted OER activity by 86.58% (normalized by ECSA) due to enhanced redox reactivities and optimal binding of intermediates.

Conclusions:

• Microwave-assisted decoration of Ru NPs on LDH provides a tunable approach to enhance OER electrocatalysis.
• The optimized catalyst exhibits superior performance, attributed to synergistic effects between Ru NPs and the LDH support.
• Experimental and theoretical findings confirm the correlation between NP concentration and OER activity, offering insights for designing advanced electrocatalysts.