• Scavenger nanoparticles could make fuel

    From ScienceDaily@1:317/3 to All on Thu Mar 31 22:30:46 2022
    Scavenger nanoparticles could make fuel cell-powered vehicles a reality
    New material prevents inexpensive catalysts from degrading

    Date:
    March 31, 2022
    Source:
    University of Illinois Chicago
    Summary:
    Engineers have developed a material that could give fuel cell
    systems a competitive edge over the battery systems that currently
    power most electric vehicles.



    FULL STORY ========================================================================== Engineers at the University of Illinois Chicago are among a collaborative
    team that has developed a material that could give fuel cell systems
    a competitive edge over the battery systems that currently power most
    electric vehicles.


    ==========================================================================
    In contrast to lithium batteries, fuel cell technology relies on catalyst- driven chemical reactions to create energy. Lithium batteries can
    typically achieve a range of 100-300 miles on one charge, but they also
    are vulnerable to the high cost of cathode materials and manufacturing
    and require several hours to charge. Alternatively, fuel cell systems
    take advantage of abundant elements such as oxygen and hydrogen and can
    achieve more than 400 miles on a single charge -- which can be done in
    under five minutes. Unfortunately, the catalysts used to power their
    reactions are made of materials that are either too expensive (i.e.,
    platinum) or too quickly degraded to be practical.

    Until now, that is. With the development of the new additive material, scientists can make an inexpensive iron-nitrogen-carbon fuel cell catalyst
    more durable. When added to the chemical reactions, the additive material protects fuel cell systems from two of its most corrosive byproducts:
    unstable particles like atoms, molecules or ions called free radicals
    and hydrogen peroxide.

    Findings from their experiments are reported in the science journal
    Nature Energy.

    Reza Shahbazian-Yassar, professor of mechanical and industrial engineering
    at the UIC College of Engineering, and colleagues used advanced imaging techniques to investigate the reactions with the material, an additive comprised of tantalum-titanium oxide nanoparticles that scavenge and
    deactivate the free radicals. The high-resolution imaging of the atomic structures allowed the scientists to define the structural parameters
    needed for the additive to work.

    "In our lab, we are able to use electron microscopy to capture
    highly detailed, atomic-resolution images of the materials under a
    variety of service conditions," said study co-corresponding author Shahbazian-Yassar. "Through our structural investigations, we learned
    what was happening in the atomic structure of additives and were able
    to identify the size and dimensions of the scavenger nanoparticles,
    the ratio of tantalum and titanium oxide. This led to an understanding
    of the correct state of the solid solution alloy required for the
    additive to protect the fuel cell against corrosion and degradation." Experiments revealed that a solid solution of tantalum and titanium
    oxide is required and that the nanoparticles should be around five
    nanometers. The experiments also revealed that a 6-4 ratio of tantalum
    to titanium oxide is required.

    "The ratio is the key to the radical scavenging properties of the
    nanoparticle material and the solid-state solution helped sustain the
    structure of the environment," Shahbazian-Yassar said.

    The experiments showed that when the scavenger nanoparticle material
    was added to the reactions of fuel cell systems, hydrogen peroxide yield
    was suppressed to less than 2% -- a 51% reduction -- and current density
    decay of fuel cells was reduced from 33% to only 3%.

    "Fuel cells are an attractive alternative to batteries because of their
    higher driving range, fast recharging capabilities, lighter weight,
    and smaller volume, provided that we can find more economical ways to
    separate and store hydrogen," Shahbazian-Yassar said. "In this paper,
    we report on an approach that gets us much closer to making fuel
    cell-powered vehicles and other fuel cell technologies a reality."
    The U.S. Department of Energy, the National Science Foundation and the
    Maryland Nanocenter supported the research.


    ========================================================================== Story Source: Materials provided by University_of_Illinois_Chicago. Note: Content may be edited for style and length.


    ========================================================================== Journal Reference:
    1. Hua Xie, Xiaohong Xie, Guoxiang Hu, Venkateshkumar Prabhakaran,
    Sulay
    Saha, Lorelis Gonzalez-Lopez, Abhijit H. Phakatkar, Min Hong,
    Meiling Wu, Reza Shahbazian-Yassar, Vijay Ramani, Mohamad
    I. Al-Sheikhly, De-en Jiang, Yuyan Shao, Liangbing Hu. Ta-TiOx
    nanoparticles as radical scavengers to improve the durability of
    Fe-N-C oxygen reduction catalysts. Nature Energy, 2022; 7 (3):
    281 DOI: 10.1038/s41560-022-00988- w ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2022/03/220331101548.htm

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