Fossil fuel use, ranging from electricity generating power plants to automobiles, pumps billions of tons of greenhouse gases into the atmosphere annually, changing the climate in ways that are likely to be detrimental to future generations.
The rising use of fossil fuels, driven by population growth and rising standards of living across the globe, adds to the urgency of finding a solution to the problem of rapidly increasing atmospheric carbon dioxide, the major greenhouse gas. At Penn State, a team of researchers led by Craig Grimes has come up with an ingenious method of turning captured CO2 into methane, a combustible fuel, using the energy of the sun.
Writing in Nano Letters (Volume 9, 2009, pp 731-737), Grimes and his team describe a highly efficient photocatalyst that can yield significant amounts of methane, other hydrocarbons, and hydrogen in a simple, inexpensive process. The team used arrays of nitrogen-doped titania nanotubes sputter-coated with an ultrathin layer of a platinum and/or copper co-catalyst(s). The titania captures high energy ultraviolet wavelengths, while the copper shifts the bandgap into the visible wavelengths to better utilize the part of the solar spectrum where most of the energy lies. In addition, the thin-walled nanotubes increase the transport ability of the charge carriers by reducing the chance for recombination of the electron with the hole.
The nanotube arrays were placed inside a stainless steel chamber filled with carbon dioxide infused with water vapor. The chamber was then set outdoors in sunlight; after a few hours the team measured the amount of CO2 converted into useful fuels. The results showed 160 µL of methane per hour per gram of nanotubes, a conversion rate approximately 20 times higher than previous efforts done under laboratory conditions using pure UV light.
“Copper oxide and titanium dioxide are common materials,” Grimes says. “We can tune the reaction using platinum nanoparticles or ideally other, less expensive catalysts.” Grimes believes that the conversion process can readily be improved by several orders of magnitude, which could make the process economically feasible.
“You could have a small scale solar condenser and a concentrated source of CO2 in a closed loop cycle to make a portable fuel. It’s a good way of storing energy for when the sun goes down,” he suggests. Inexpensive solar concentrators could improve the process, as the photocatalytic CO2 conversion appears to scale with the intensity of sunlight.
Capturing CO2 at source points, such as fossil fuel (coal, natural gas, etc.)-burning power plants, and turning it into a transportation fuel in a cheap, sunlight-driven process could dramatically improve the economics of CO2 capture. “Then maybe we could figure out how to capture and reuse the CO2 in our vehicles and none of it would go back into the atmosphere,” Grimes proposes.
Future research will look into increasing conversion rates by modifying the co-catalysts and changing the reactor design from a batch reactor to a flow-through photocatalytic design. “We are now reaching for low hanging fruit,” Grimes says. “There is plenty of opportunity for dramatic improvements.”
The article authors are Materials Research Institute scientists Oomman K. Varghese, Ph.D. and Maggie Paulose, Ph.D.; Thomas J. LaTempa, a graduate student in the Department of Electrical Engineering; and Craig A. Grimes, Ph.D., a professor of electrical engineering and materials science and engineering, as well as a faculty member in the Materials Research Institute at Penn State.
Litter is present throughout the world’s oceans: 1,220 species affected
27.03.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung
International network connects experimental research in European waters
21.03.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
30.03.2017 | Health and Medicine
30.03.2017 | Health and Medicine
30.03.2017 | Medical Engineering