Interfacial Engineering and Structural Modulation of RuO₂-Based Catalysts for Highly Active and Durable Oxygen...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Commercializing green hydrogen production via water splitting requires active and durable catalysts for the oxygen evolution reaction (OER) in acidic media.
• Ruthenium oxide (RuO2) based materials are promising OER catalysts, but their activity and stability need enhancement for practical applications.

Purpose of the Study:

• To fabricate and characterize a novel cobalt oxide (Co3O4)-synergized nickel-doped ruthenium oxide (Ni-RuO2) heterojunction on reduced graphene oxide (Co3O4/Ni-RuO2/rGO).
• To evaluate the electrocatalytic activity and durability of the developed Co3O4/Ni-RuO2/rGO catalyst for the OER in acidic electrolytes.
• To elucidate the synergistic effects of the heterojunction structure and Ni doping on the catalyst's electronic properties and OER performance.

Main Methods:

• Fabrication of a Co3O4/Ni-RuO2/rGO heterojunction electrocatalyst.
• Advanced characterization techniques to analyze the catalyst's structure and electronic properties.
• Electrochemical testing in acidic electrolytes to assess OER activity and durability.
• Density functional theory (DFT) calculations and in situ Raman analysis to understand reaction mechanisms.

Main Results:

• The Co3O4/Ni-RuO2/rGO heterojunction exhibited ultra-low overpotentials of 195 mV at 10 mA cm-2 and 305 mV at 100 mA cm-2 with only 1.36 wt% RuO2.
• The catalyst demonstrated excellent durability, maintaining performance after 100 hours of operation at 500 mA cm-2.
• Advanced characterizations and theoretical calculations confirmed the crucial role of the heterojunction and Ni doping in enhancing OER activity and stability.

Conclusions:

• The developed Co3O4/Ni-RuO2/rGO heterojunction is a highly active and durable electrocatalyst for the oxygen evolution reaction in acidic media.
• The synergistic interaction between Co3O4, Ni-RuO2, and rGO, along with Ni doping, significantly boosts catalytic performance.
• This study offers a promising strategy for designing cost-effective and high-performance electrocatalysts for advanced energy conversion technologies like green hydrogen production.