Core / shell-type catalyst particles and methods for their preparation
AssigneeUmicore AG & Co. KG
InventorsMarco LOPEZ, Michael LENNARTZ, Dan V. GOIA, Carsten BECKER, Stephanie CHEVALLIOT
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Abstract
The invention discloses core/shell type catalyst particles comprising a Mcore/Mshell structure with Mcore=inner particle core and Mshell=outer particle shell, wherein the medium diameter of the catalyst particle (dcore+shell) is ≧20 nm. The thickness of the outer shell (tshell) comprises at least 3 atomic layers. The core/shell type catalyst particles, particularly the particles comprising a Pt-based shell, reveal a high specific activity. The catalyst particles are preferably supported on suitable support materials such as carbon black and are used as electrocatalysts for fuel cells.
Claims17
Catalyst particles comprising a Mcore/Mshell structure with
- Mcore=metal of inner particle core
- Mshell=metal of outer particle shell
- wherein the medium diameter of said catalyst particles (dcore+shell) is ≧20 nm and wherein said particles exhibit increased stability towards sintering, leaching and Ostwald ripening.
Method for manufacture of an electrocatalyst comprising catalyst particles based on a Mcore/Mshell structure with
- Mcore=metal of inner particle core
- Mshell=metal of outer particle shell
- and a medium diameter of the catalyst particles (dcore+shell)≧20 nm, the method comprising preparing the inner particle core (Mcore) of the catalyst particles by a wet chemical reduction method.
Method for manufacture of an electrocatalyst comprising catalyst particles based on a Mcore/Mshell structure with
- Mcore=metal of inner particle core
- Mshell=metal of outer particle shell
- and a medium diameter of the catalyst particles (dcore+shell)≧20 nm, the method comprising preparing the outer particle shell (Mshell) of the catalyst particles by a method selected from the group consisting of electroplating, cementation, UPD, plasma coating, vapor deposition and PVD/CVD methods.
Dependencies are inferred from the claim text.