Umicore Ag & Co Kg

Carsten Becker

Marco Lopez

Dan V Goia

Michael Lennartz

Stéphanie Chevalliot

Daniel Herein

Barbara Klose-Schubert

The invention relates to a carbon-free electrocatalyst for fuel cells, containing an electrically conductive substrate and a catalytically active species, wherein the conductive substrate is an inorganic, multi-component substrate material of the composition 0X1-0X2, in which 0X1 means an electrically non-conductive inorganic oxide having a specific surface area (BET) in the range of 50 to 400 mVg and 0X2 means a conductive oxide. The non-conductive inorganic oxide 0X1 is coated with the conductive oxide 0X2. The multi-component substrate preferably has a core/shell structure. The multi-component substrate material 0X1-0X2 has an electrical conductivity in the range&#x3e;0.01 S/cm and is coated with catalytically active particles containing noble metal. The electrocatalysts produced therewith are used in electrochemical devices such as PEM fuel cells and exhibit high corrosion stability.

Electrocatalyst for fuel cells and method for producing said electrocatalyst

The invention discloses core/shell, type catalyst particles comprising a M/Mstructure with M=inner particle core and M=outer particle shell, wherein the medium diameter of the catalyst particle (d) is in the range of 20 to 100 nm, preferably in the range of 20 to 50 nm. The thickness of the outer shell (t) is about 5 to 20% of the diameter of the inner particle core of said catalyst particle, preferably comprising at least 3 atomic layers. The core/shell type catalyst particles, particularly the particles comprising a Pt&#x2dc;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.

Core/shell-type catalyst particles and methods for their preparation

The invention discloses core/shell type catalyst particles comprising a M/Mstructure with M=inner particle core and M=outer particle shell, wherein the medium diameter of the catalyst particle (d) is in the range of 20 to 100 nm, preferably in the range of 20 to 50 nm. The thickness of the outer shell (t) is about 5 to 20% of the diameter of the inner particle core of said catalyst particle, preferably comprising 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.

The invention discloses core/shell type catalyst particles comprising a M/Mstructure with M=inner particle core and M&#x2212;outer particle shell, wherein the medium diameter of the catalyst particle (d) is &#x2267;20 nm. The thickness of the outer shell (t) 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.

The invention is directed to core/shell type catalyst particles comprising a M/Mstructure with M=inner particle core and M=outer particle shell, wherein the medium diameter of the catalyst particle (d+) is in the range of 20 to 100 nm, 5 preferably in the range of 20 to 50 nm. The thickness of the outer shell (t) is about 5 to 20% of the diameter of the inner particle core of said catalyst particle, preferably comprising at least 3 atomic layers. The inner particle core (M) of the particles comprises metal or ceramic materials, whereas the material of the outer shell (M) comprises precious metals and/or alloys thereof. The core/shell type catalyst particles are preferably supported on suitable support materials such as carbon black and can be used as electrocatalysts for fuel cells and for other catalytic applications.

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Niedernberg, Germany

Carsten Becker