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The discovery provides a new low cost and efficient
option for hydrogen production and can be used for a variety of
distributed energy applications.
Pratim Biswas, Ph.D., the Stifel and Quinette Jens
Professor and Chair of the Department of Energy, Environmental and
Chemical Engineering, and his graduate student Elijah Thimsen,
recently have developed the well-controlled, gas phase process, and
have demonstrated it for synthesizing a variety of oxide
semiconductors such as iron and titanium dioxide films in a single
step process . It is based on a simple, inexpensive flame aerosol
reactor (FLAR) and consists of four mass flow controllers to regulate
process gases, a standard bubbler to deliver a precursor, a metal tube
that acts as a burner and a water-cooled substrate holder.
"We put these films in water and they promote some
reactions that split water into hydrogen and oxygen," said Biswas. "We
can use any oxide materials such as titanium dioxide, tungsten oxide
and iron oxide in nanostructures sandwiched together that make very
compact structures. The process is direct and takes only a few minutes
to fabricate. More important, these processes can be scaled up to
produce larger structures in a very cost effective manner in
atmospheric pressure processes ."
Collaborations have now been established with Dewey
Holten, Ph.D., Washington University professor of chemistry in Arts &
Sciences, to better understand the electron-hole pair kinetics,
information that can then be used to tune the synthesis process. Other
collaborations with Robert Blankenship, Ph.D., Washington University
professor of biology and chemistry in Arts & Sciences, are being
explored to create hybrid bio-nanostructures that will improve the
light absorption efficiencies over a broader range of wavelengths.
Electrospray and other aerosol techniques are being used to create
these hybrid films. |
