Page 32 - Environmental Nanotechnology Applications and Impacts of Nanomaterials

18 Nanotechnology as a Tool for Sustainability

Nanotechnology could also play a pivotal role in providing stronger,
lighter materials to build lighter-weight vehicles and to provide safer,
more cost-effective storage for hydrogen fuels. Nanotechnology can
play a key role in the development of sturdier fuel cells and improved
membrane technology by providing new, light materials that can
withstand the large changes in temperatures required in automotive
operations.
At present, polymer electrolyte membranes are the most common
membranes commercially available. But scientists are working to
develop ceramic electrolyte membranes that will be more durable under
extreme conditions. Nanostructured ceramic membranes, derived from
metal-oxane nanoparticles, could present an improvement in the effi-
ciency of fuel cells.
The Materials Nanotechnology Research Group at the University of
Nevada, Reno, under the direction of Dr. Manoranjan Misra, professor
of materials science in the Department of Chemical and Metallurgical
Engineering, has developed titanium dioxide nanotube arrays for gen-
erating hydrogen by splitting water using sunlight. Once the process is
scaled up to generate a lot of hydrogen from water, it will have great
potential as a clean energy resource.
This new method splits water molecules, creating hydrogen energy
more efficiently than currently available. The fabrication and produc-
tion of nanotubes is done by a simple electrochemical method. University
scientists add different tubular materials to increase the water-splitting
efficiency and using sunlight.
“We can put one trillion nanotube-holes in solid titanium oxide sub-
strate, which is approximately the size of thumbnails,” said Misra. Each
of these holes, a thousand times smaller than a human hair, acts as
nanoelectrodes.
The hydrogen project also stores hydrogen in nanoporous titanium and
carbon nanotube assemblies. These nanomaterials are powerful enough
to maintain hydrogen for use in vehicles.
Among the major energy nanotechnology grand challenges are the
following, according to a Smalley Institute for Nanoscale Science and
Technology/James A. Baker III Institute for Public Policy study on the
subject:

■ Lower costs of photovoltaic solar energy by tenfold
■ Achieve commercial photocatalytic reduction of CO 2 to methanol
■ Create a commercial process for direct photoconversion of light and
water to produce hydrogen
■ Lower the costs of fuel cells by ten- to a hundred-fold and create new,
sturdier materials