Ordered mesoporous Pt-Ru-Ir nanostructures as superior bifunctional electrocatalyst for oxygen reduction/oxygen...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing efficient electrocatalysts is crucial for electrochemical energy conversion and storage.
• Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are key reactions in many energy devices.
• Platinum-based alloys are commonly used but often require high noble metal content.

Purpose of the Study:

• To synthesize and characterize an efficient oxygen bifunctional catalyst using Pt-Ru-Ir with ordered mesoporous nanostructures (OMNs).
• To investigate the influence of OMNs and iridium (Ir) content on the electrocatalytic activity for both ORR and OER.
• To evaluate the synergistic and electronic effects governing the catalyst's performance.

Main Methods:

• Synthesis of Pt-Ru-Ir OMNs catalyst via chemical reduction using KIT-6 silica template.
• Characterization using X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM).
• Electrochemical evaluation of ORR and OER activity and durability.

Main Results:

• The OMNs Pt70Ru25Ir5 catalyst exhibited significantly enhanced mass and specific activity for ORR compared to benchmark Pt/C.
• This catalyst also demonstrated superior OER activity, outperforming commercial IrO2.
• The Pt70Ru25Ir5 catalyst showed extended durability for both ORR and OER after 6000 cycles.

Conclusions:

• Ordered mesoporous nanostructures and synergistic electronic effects in Pt-Ru-Ir catalysts enhance bifunctional electrocatalytic activity.
• Pt-Ru-Ir OMNs with low Ir content (around 5 wt%) represent a promising catalyst for electrochemical energy conversion and storage.
• This catalyst design offers a pathway to reduce noble metal loading while maintaining high performance.