Navigation Links
Platinum-rich shell, platinum-poor core
Date:10/23/2007

This release is available in German.

Hydrogen fuel cells will power the automobiles of the future; however, they have so far suffered from being insufficiently competitive. At the University of Houston, Texas, USA, a team led by Peter Strasser has now developed a new class of electrocatalyst that could help to improve the capacity of fuel cells. The active phase of the catalyst consists of nanoparticles with a platinum-rich shell and a core made of an alloy of copper, cobalt, and platinum. This catalyst demonstrates the highest activity yet observed for the reduction of oxygen.

Hydrogen fuel cells are a tamed version of the explosive reaction that occurs between oxygen and hydrogen gases to form water. To allow the reaction to proceed gently and the energy released to be tapped in the form of an electrical current, the reactants are separated within the fuel cell, and each half-reaction occurs in its own chamber. In one half-cell, oxygen takes up electrons from an electrode (reduction); in the other, hydrogen gas gives up electrons (oxidation). The cells are linked by a polymer electrolyte membrane, across which exchange occurs.

To get the reaction to proceed, the electrodes must be catalytic. For decades, the material of choice for the electrode in the oxygen half-reaction has been the precious metal platinum. Now, Strasser and his team have developed a new material, an alloy of platinum, copper, and cobalt that is deposited onto carbon supports in the form of nanoparticles. The active catalytic phase is formed in situ: when a cyclic alternating current is applied to the electrode, the less precious metals, especially the copper, on the surface of the nanoparticles separate from the alloy. This process results in nanoparticles with a core made of the original copper-rich alloy and a shell containing almost exclusively platinum.

The oxygen-reducing activity of our new electrocatalytic material is unsurpassedit is four to five times higher than that of pure platinum. In addition, we have demonstrated how to incorporate and activate this material in situ in a fuel cell, says Strasser. The observed increase in surface area of the nanoparticles is not enough to explain the increased activity. Strasser suspects that special altered structural characteristics of the surface play a role. Although the surface consists mostly of platinum, the distances between the platinum atoms on the particle surface seem to be shorter than those in pure platinum. This compression can be stabilized by the alloy core, which shows even shorter Pt-Pt distances because of the presence of copper and cobalt. In addition, the copper-rich core seems to influence the electronic properties of the platinum shell. Theoretical calculations have suggested that the oxygen can thus bind optimally to the particle surface, allowing it to be more easily reduced.


'/>"/>

Contact: Peter Strasser
pstrasser@uh.edu
713-743-4310
John Wiley & Sons, Inc.
Source:Eurekalert

Post Your Comments:
*Name:
*Comment:
*Email:
(Date:10/11/2017)... , ... October 11, 2017 , ... ... (FDA) has granted orphan drug designation to SBT-100, its novel anti-STAT3 (Signal Transducer ... treatment of osteosarcoma. SBT-100 is able to cross the cell membrane and bind ...
(Date:10/10/2017)... ... 10, 2017 , ... For the second time in three ... Mentoring Award. Representatives of the FirstHand program travelled to Washington, D.C. Tuesday, October ... US2020’s mission is to change the trajectory of STEM education in America by ...
(Date:10/10/2017)... Calif. , Oct. 10, 2017 SomaGenics ... from the NIH to develop RealSeq®-SC (Single Cell), expected ... for profiling small RNAs (including microRNAs) from single cells ... Program highlights the need to accelerate development of approaches ... "New techniques for measuring levels ...
(Date:10/9/2017)... , Oct. 9, 2017  BioTech Holdings announced ... by which its ProCell stem cell therapy prevents ... ischemia.  The Company, demonstrated that treatment with ProCell ... limbs saved as compared to standard bone marrow ... HGF resulted in reduction of therapeutic effect.  ...
Breaking Biology Technology:
(Date:4/3/2017)...  Data captured by IsoCode, IsoPlexis Corporation,s ... statistically significant association between the potency of ... objective response of cancer patients post-treatment. The ... cancer patients will respond to CAR-T cell ... to improve both pre-infusion potency testing and cell ...
(Date:3/30/2017)... The research team of The Hong Kong ... identification by adopting ground breaking 3D fingerprint minutiae recovery and matching ... and accuracy for use in identification, crime investigation, immigration control, security ... ... A research team led by ...
(Date:3/29/2017)... CHICAGO , March 29, 2017  higi, the ... ecosystem in North America , today ... Partners and the acquisition of EveryMove. The new investment ... extensive set of tools to transform population health activities ... and lifestyle data. higi collects and secures ...
Breaking Biology News(10 mins):