Platinum-based oxygen reduction electrocatalysts.

Area of Science:

• Electrocatalysis
• Materials Science
• Energy Conversion

Background:

• Efficient oxygen reduction reaction (ORR) is crucial for clean energy generation in proton-exchange membrane fuel cells.
• High cost and declining activity of platinum (Pt) catalysts hinder widespread fuel cell adoption.
• Current research focuses on novel catalyst structures to enhance ORR performance and cost-effectiveness.

Purpose of the Study:

• To review recent advancements in the design of Pt-based electrocatalysts for the ORR.
• To explore synthetic strategies for creating highly active and stable ORR catalysts.
• To provide insights into reaction mechanisms and factors influencing catalyst performance.

Main Methods:

• Design and synthesis of Pt-based catalysts, including bimetallic nanoparticles and nanostructures.
• Control over catalyst shape (facet) and size, surface composition, and structure (e.g., core-shell, hollow porous).
• Utilizing carbon-monoxide (CO)-assisted reduction for controlled facet synthesis and density functional theory (DFT) for performance prediction.

Main Results:

• Development of highly active catalysts such as extended single crystal surfaces, bimetallic nanoparticles, and low-dimensional nanostructures.
• Demonstration that controlling nanocrystal facet ({111}) and size significantly impacts ORR activity.
• Identification of surface strain and composition as critical factors influencing ORR performance.

Conclusions:

• Strategic design of Pt-based catalysts, focusing on facet, size, and surface properties, is key to improving ORR activity and stability.
• Advanced synthetic methods, like CO-assisted reduction, enable precise control over catalyst nanostructures.
• Standardized protocols for half-cell measurements are needed for consistent evaluation of ORR catalyst performance.