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Platinum-Coated Non-Noble Metal-Noble Metal Core-Shell Electrocatalysts

Brookhaven National Laboratory

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Technology Marketing Summary

Platinum is a very good, albeit expensive, electrocatalyst. In order to increase the catalytic activity of an electrocatalyst per mass platinum (the platinum mass activity), nanoparticles of less expensive materials are coated with atomically thin layers of platinum. The nanoparticles have a core-shell structure and include palladium, gold, and their alloys with other transition metals. The platinum-coated composite can be used as an electrocatalyst in place of pure platinum, for example, in fuel cells.

Description

A particle composite includes a nanoparticle having a core at least partially encapsulated by a shell of a different composition, the resulting core-shell nanoparticle at least partially encapsulated by an atomically thin layer of platinum. Particularly useful composites include platinum-encapsulated core-shell nanoparticles in which the core is a first-row transition metal and the shell is a noble metal other than platinum. The core-shell nanoparticles may be formed by subjecting a homogeneous allow of a noble metal and a non-noble metal to a heat treatment during which segregation of elements occurs, resulting in a core highly enriched in the non-noble metal and a shell highly enriched in the noble metal.

Benefits

High noble-metal mass activity allows for reduced incorporation of expensive materials such as platinum, resulting in lower overall costs for the inventive electrocatalysts.

Applications and Industries

Fuel cell catalysts; oxygen-reduction; heterogeneous catalysis.

More Information

Zhang, et al., “Platinum Monolayer on Nonnoble Metal−Noble Metal Core−Shell Nanoparticle Electrocatalysts for O2 Reduction,” J. Phys. Chem. B, 109, 22701–22704 (2005). DOI: 10.1021/jp055634c

Patents and Patent Applications
ID Number
Title and Abstract
Primary Lab
Date
Patent 9,005,331
Patent
9,005,331
Platinum-coated non-noble metal-noble metal core-shell electrocatalysts
Core-shell particles encapsulated by a thin film of a catalytically active metal are described. The particles are preferably nanoparticles comprising a non-noble core with a noble metal shell which preferably do not include Pt. The non-noble metal-noble metal core-shell nanoparticles are encapsulated by a catalytically active metal which is preferably Pt. The core-shell nanoparticles are preferably formed by prolonged elevated-temperature annealing of nanoparticle alloys in an inert environment. This causes the noble metal component to surface segregate and form an atomically thin shell. The Pt overlayer is formed by a process involving the underpotential deposition of a monolayer of a non-noble metal followed by immersion in a solution comprising a Pt salt. A thin Pt layer forms via the galvanic displacement of non-noble surface atoms by more noble Pt atoms in the salt. The overall process is a robust and cost-efficient method for forming Pt-coated non-noble metal-noble metal core-shell nanoparticles.
Brookhaven National Laboratory 04/14/2015
Issued
Technology Status
Technology IDDevelopment StageAvailabilityPublishedLast Updated
BSA 08-33PrototypeAvailable04/08/201104/08/2011

Contact BNL About This Technology

To: Poornima Upadhya<pupadhya@bnl.gov>