Method for Manufacturing Onion-Structured Binary Metal Catalysts

Highly Durable Onion-Structured Fuel Cell Catalysts Using Electroless Plating and Displacement Reactions

This technology synthesizes onion-structured binary metal catalysts, such as Pt-Cu-Pt, by applying a heterogeneous metal shell layer onto core metal nanoparticles via electroless plating, followed by a secondary coating of the core metal using an aqueous displacement reaction based on differences in reduction potential.

Conventional multi-layered metal catalysts required electrodes and complex processes, as they relied on UPD-based electroplating to form metal layers. This made it difficult to mass-produce high-activity fuel cell catalysts.

This technology enables the mass production of catalysts through a simple aqueous process, as it forms layers using only plating solutions and metal precursors without the need for electrodes. The unique electronic properties of the onion structure enhance oxygen reduction activity and durability. Applicable to hydrogen fuel cell cathode catalysts and various alloy electrochemical catalysts, it allows for the large-scale supply of highly durable catalysts with improved platinum utilization efficiency.

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Key Features:

• Preparing core metal nanoparticles, which serve as the center of the onion-structured catalyst, supported on a carbon substrate
• Mixing the core metal nanoparticles with an electroless plating solution containing metal salts, reducing agents, complexing agents, and pH adjusters to form a heterogeneous metal shell layer
• Re-forming a layer of the same metal as the core onto the shell layer via an aqueous displacement reaction utilizing differences in reduction potential
• Sequentially forming a Cu shell layer and a Pt layer on a Pt nanoparticle core, and repeating the plating steps according to the desired number of metal thin films to produce an onion-structured Pt-Cu-Pt catalyst

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