Catalyst
AssigneesJohnson Matthey Fuel Cells Limited, GM Global Technology Operations LLC
InventorsAlejandro Martinez BONASTRE, Rachel Louise O'MALLEY, Geoffrey Hugh SPIKES, Frederick Tadeusz WAGNER
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Abstract
A de-alloyed catalyst of formula PtXY, wherein X is selected from the group consisting of Ni, Co and Cr; and Y is selected from the group consisting of Zn, Al, Sn, Be, Pb, Ga, V, In, Y, Sr and Ti; characterised in that the total atomic composition relative to Pt of X and Y at the surface of the de-alloyed catalyst as determined from X-ray photoelectron spectroscopy is between 20 and 99% lower than the total atomic composition relative to Pt of X and Y in the bulk of the de-alloyed catalyst is disclosed.
Claims21
1-18. (canceled)
A de-alloyed catalyst of formula PtXY, wherein X is selected from the group consisting of Ni, Co and Cr;
- and Y is selected from the group consisting of Zn, Al, Sn, Be, Pb, Ga, V, In, Y, Sr and Ti;
- characterised in that the total atomic composition relative to Pt of X and Y at the surface of the de-alloyed catalyst as determined from X-ray photoelectron spectroscopy is between 20 and 99% lower than the total atomic composition relative to Pt of X and Y in the bulk of the de-alloyed catalyst.
A de-alloyed catalyst of formula PtXY, wherein X is selected from the group consisting of Ni, Co and Cr;
- and Y is selected from the group consisting of Zn, Al, Sn, Be, Pb, Ga, V, In, Y, Sr and Ti;
- characterised in that the total atomic composition relative to Pt of X and Y at the surface of the de-alloyed catalyst as determined from X-ray photoelectron spectroscopy is between 20 and 99% less than the total atomic composition relative to Pt of X and Y in the bulk of the de-alloyed catalyst;
- said de-alloyed catalyst obtainable by a process comprising the steps of:
- (i) preparing a catalyst alloy precursor of formula PtXY;
- (ii) subjecting the catalyst alloy precursor to conditions sufficient to leach a portion of X and/or Y from the catalyst alloy precursor to provide the de-alloyed catalyst.
A process for preparing a de-alloyed catalyst of formula PtXY, wherein X is selected from the group consisting of Ni, Co and Cr;
- and Y is selected from the group consisting of Zn, Al, Sn, Be, Pb, Ga, V, In, Y, Sr and Ti;
- characterised in that the total atomic composition relative to Pt of X and Y at the surface of the de-alloyed catalyst as determined from X-ray photoelectron spectroscopy is between 20 and 99% less than the total atomic composition relative to Pt of X and Y in the bulk of the de-alloyed catalyst;
- said process comprising the steps of:
- (i) preparing a catalyst alloy precursor of formula PtXY wherein the atomic percentage of the total of X and Y in the catalyst alloy precursor is at least 50 atomic percent;
- (ii) subjecting the catalyst alloy precursor to conditions sufficient to leach a portion of X and/or Y from the catalyst alloy precursor to provide the de-alloyed catalyst.
Dependencies are inferred from the claim text.