| Tweet |
http://www.newscientist.com/article/dn16621-sunpowered-device-converts-co2-into-fuel.html
最後にこのコラムへの読者のコメントの幾つかを載せています。
Sun-powered device converts CO2 into fuel
Powered only by natural sunlight, an array of nanotubes is able to convert a mixture of carbon dioxide and water vapour into natural gas at unprecedented rates.
Such devices offer a new way to take carbon dioxide from the atmosphere and convert it into fuel or other chemicals to cut the effect of fossil fuel emissions on global climate, says Craig Grimes, from Pennsylvania State University, whose team came up with the device.
Although other research groups have developed methods for converting carbon dioxide into organic compounds like methane, often using titanium-dioxide nanoparticles as catalysts, they have needed ultraviolet light to power the reactions.
The researchers' breakthrough has been to develop a method that works with the wider range of visible frequencies within sunlight.
Enhanced activity
The team found it could enhance the catalytic abilities of titanium dioxide by forming it into nanotubes each around 135 nanometres wide and 40 microns long to increase surface area. Coating the nanotubes with catalytic copper and platinum particles also boosted their activity.
The researchers housed a 2-centimetre-square section of material bristling with the tubes inside a metal chamber with a quartz window. They then pumped in a mixture of carbon dioxide and water vapour and placed it in sunlight for three hours.
The energy provided by the sunlight transformed the carbon dioxide and water vapour into methane and related organic compounds, such as ethane and propane, at rates as high as 160 microlitres an hour per gram of nanotubes. This is 20 times higher than published results achieved using any previous method, but still too low to be immediately practical.
If the reaction is halted early the device produces a mixture of carbon monoxide and hydrogen known as syngas, which can be converted into diesel.
Copper boost
"If you tried to build a commercial system using what we have accomplished to date, you'd go broke," admits Grimes. But he is confident that commercially viable results are possible.
"We are now working on uniformly sensitising the entire nanotube array surface with copper nanoparticles, which should dramatically increase conversion rates," says Grimes, by at least two orders of magnitude for a given area of tubes.
This work suggests a "potentially very exciting" application for titanium-dioxide nanotubes, says Milo Shaffer, a nanotube researcher at Imperial College, London. "The high surface area, small critical dimensions, and open structure [of these nanotubes] apparently provide a relatively high activity," he says.
＊＊＊＊＊
以下読者からのコメントのいくつか。
（１）Wed Feb 18 11:38:53 GMT 2009 by Matt
What a marvellous development this may prove to be. A 'kill two birds with one stone' solution, by removing excess CO2 from the atmosphere whilst also providing more fuel for growing energy demand. It may be a while off yet but it's exciting none the less. More power to nanotechnology I say!
英語人にも一石ニ鳥という表現があるんですな。
（２）Wed Feb 18 11:55:09 GMT 2009 by simon smart
It's not going to decrease the concentration of CO2 though if the fuel is burnt is it!
（３）No, but it would provide a sustainable fuel that would not add to CO2 levels. Burning fossil fuels releases CO2 that wasn't in the atmosphere before.
（４）Perhaps not the same carbon with the same oxygen, but it was in the air before - just hundreds of millions of years ago. I'd go with using the term "net gain in atmospheric CO2."
Burning fossil fuels has a net gain in atmospheric CO2, this process is carbon neutral if you burn it, and I still don't understand why you couldn't just pump it back into the ground and seal it off.
投稿コメント全ログ コメント即時配信 スレ建て依頼 削除コメント確認方法
題名には必ず「阿修羅さんへ」と記述してください。
掲示板,ＭＬを含むこのサイトすべての
一切の引用、転載、リンクを許可いたします。確認メールは不要です。
引用元リンクを表示してください。