Surface Composition of a Highly Active Pt3Y Alloy Catalyst for Application in Low Temperature Fuel Cells

• Currently, platinum is the most widely used catalyst for low temperature proton exchange membrane fuel cells (PEMFC). However, the kinetics at the cathode are slow, and the price of platinum is high. To improve oxygen reduction reaction (ORR) kinetics at the cathode, platinum can be alloyed with rare earth elements, such as yttrium. We report that Pt3Y has the potential to be over 2 times more active for the ORR compared with Pt inside a real fuel cell. We present detailed photoemission analysis into the nature of the sputtered catalyst surface, using synchrotron radiation photoelectron spectroscopy (SRPES) to examine if surface adsorbates or impurities are present and can be removed. Pretreatment removes most of the yttrium oxide in the surface leaving behind a Pt overlayer which is only a few monolayers thick. Evidence of a substochiometric oxide peak in the Y 3d core level is presented, this oxide extends into the surface even after Ar+ sputter cleaning in-situ. This information will aid the development of new highly active nanocatalysts for employment in real fuel cell electrodes.

Ämnesord

NATURVETENSKAP  -- Kemi -- Oorganisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Inorganic Chemistry (hsv//eng)

NATURVETENSKAP  -- Kemi -- Materialkemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Materials Chemistry (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Kemiteknik -- Annan kemiteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Chemical Engineering -- Other Chemical Engineering (hsv//eng)

NATURVETENSKAP  -- Fysik -- Annan fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Other Physics Topics (hsv//eng)

Nyckelord

Alloys

Electrocatalysis

Oxygen Reduction Reaction

Photoelectron Spectroscopy

Platinum

Proton Exchange Membrane Fuel Cells

Rare Earths

Thin Films

Binary alloys

Cathodes

Core levels

Electrolytic reduction

Nanocatalysts

Platinum alloys

Reaction kinetics

Synchrotron radiation

Temperature

Yttrium alloys

Yttrium metallography

Yttrium oxide

Catalyst surfaces

Fuel cell electrodes

Low temperature fuel cells

Low temperatures

Photoemission analysis

Sputter cleaning

Surface adsorbates

Synchrotron radiation photoelectron spectroscopy

Proton exchange membrane fuel cells (PEMFC)

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