Expanding on work published two years ago, MIT’s Daniel Nocera and his associates have found yet another formulation, based on inexpensive and widely available materials, that can efficiently catalyze the splitting of water molecules using electricity. This could ultimately form the basis for new storage systems that would allow buildings to be completely independent and self-sustaining in terms of energy: The systems would use energy from intermittent sources like sunlight or wind to create hydrogen fuel, which could then be used in fuel cells or other devices to produce electricity or transportation fuels as needed.
Nocera, the Henry Dreyfus Professor of Energy and Professor of Chemistry, says that solar energy is the only feasible long-term way of meeting the world’s ever-increasing needs for energy, and that storage technology will be the key enabling factor to make sunlight practical as a dominant source of energy. He has focused his research on the development of less-expensive, more-durable materials to use as the electrodes in devices that use electricity to separate the hydrogen and oxygen atoms in water molecules. By doing so, he aims to imitate the process of photosynthesis, by which plants harvest sunlight and convert the energy into chemical form.
Nocera pictures small-scale systems in which rooftop solar panels would provide electricity to a home, and any excess would go to an electrolyzer — a device for splitting water molecules — to produce hydrogen, which would be stored in tanks. When more energy was needed, the hydrogen would be fed to a fuel cell, where it would combine with oxygen from the air to form water, and generate electricity at the same time.
An electrolyzer uses two different electrodes, one of which releases the oxygen atoms and the other the hydrogen atoms. Although it is the hydrogen that would provide a storable source of energy, it is the oxygen side that is more difficult, so that’s where he and many other research groups have concentrated their efforts. In a paper in Science in 2008, Nocera reported the discovery of a durable and low-cost material for the oxygen-producing electrode based on the element cobalt.
Now, in research being reported in the journal Proceedings of the National Academy of Science (PNAS), Nocera, along with postdoctoral researcher Mircea Dincă and graduate student Yogesh Surendranath, report the discovery of yet another material that can also efficiently and sustainably function as the oxygen-producing electrode. This time the material is nickel borate, made from materials that are even more abundant and inexpensive than the earlier find.
Even more significantly, Nocera says, the new finding shows that the original compound was not a unique, anomalous material, and suggests that there may be a whole family of such compounds that researchers can study in search of one that has the best combination of characteristics to provide a widespread, long-term energy storage technology.
“Sometimes if you do one thing, and only do it once,” Nocera says, “you don’t know — is it extraordinary or unusual, or can it be commonplace?” In this case, the new material “keeps all the requirements of being cheap and easy to manufacture” that were found in the cobalt-based electrode, he says, but “with a different metal that’s even cheaper than cobalt.”
But the research is still in an early stage. “This is a door opener,” Nocera says. “Now, we know what works in terms of chemistry. One of the important next things will be to continue to tune the system, to make it go faster and better. This puts us on a fast technological path.” While the two compounds discovered so far work well, he says, he is convinced that as they carry out further research even better compounds will come to light. “I don’t think we’ve found the silver bullet yet,” he says. …
Archive for May 16th, 2010
New water-splitting catalyst: Researchers expand list of potential electrode materials that could be used to store energy
Posted by Xeno on May 16, 2010
Posted by Xeno on May 16, 2010
Human stem cells grown in a simulated microgravity environment develop differently than those grown under normal conditions, an Australian study has found. The finding could have implications for space colonization and long-term spaceflight.
Using a NASA-developed rotating vessel that simulates microgravity, an Australian whiz-kid researcher found the stem cells’ protein expressions were vastly different than when grown in normal Earth gravity, Discovery News reports.
About 64 percent of the proteins found in the microgravity cells were not present in control samples. The microgravity cells contained proteins involved in the breakdown of bone and the regulation of calcium, neither of which were found in regular, Earth-gravity cells. Embryonic stem cells can differentiate into any of the body’s hundreds of cell types. 21-year-old Elizabeth Blaber, who co-authored the study, presented a paper last month at an astrobiology conference in Houston.
Spaceflight wreaks havoc on the body — astronauts experience muscle atrophy, bone-density loss and slower heart rates in orbit. Plenty of research has been done in those areas, but the Australian team, supervised by Brendan Burns of the University of New South Wales in Sydney, says little has been done on the cellular level.
The finding that stem cells express different proteins under microgravity could help explain muscular and skeletal changes in adults.
The research also showed that anti-oxidant levels fell over time, which could shed light on why wounds heal more slowly in space. …
Posted by Xeno on May 16, 2010
Jupiter has lost one of its iconic red stripes and scientists are baffled as to why.
The largest planet in our solar system is usually dominated by two dark bands in its atmosphere, with one in the northern hemisphere and one in the southern hemisphere.
However, the most recent images taken by amateur astronomers have revealed the lower stripe known as the Southern Equatorial Belt has disappeared leaving the southern half of the planet looking unusually bare.
The band was present in at the end of last year before Jupiter ducked behind the Sun on its orbit. However, when it emerged three months later the belt had disappeared.
Journalist and amateur astronomer Bob King, also known as Astro_Bob, was one of the first to note the strange phenomenon.
He said: ‘Jupiter with only one belt is almost like seeing Saturn when its rings are edge-on and invisible for a time – it just doesn’t look right.’
It is not the first time this unusual phenomenon has been noticed. Jupiter loses or regains one of its belts every ten of 15 years, although exactly why this happens is a mystery.
The planet is a giant ball of gas and liquid around 500million miles from the Sun. It’s surface is composed of dense red, brown, yellow, and white clouds arranged in light-coloured areas called zones and darker regions called belts.
These clouds are created by chemicals that have formed at different heights. The highest white clouds in the zones are made of crystals of frozen ammonia. Darker, lower clouds are created from chemicals including sulphur and phosphorus. The clouds are blown into bands by 350mph winds caused by Jupiter’s rapid rotation.
Noted Jupiter watcher Anthony Wesley, who spotted an impact spot on its surface last year, has tracked the disappearing belt from his back garden in Australia.
‘It was obvious last year that it was fading. It was closely observed by anyone watching Jupiter,’ he told The Planetary Society.
‘There was a big rush on to find out what had changed once it came back into view.’
Mr Wesley said while it was a mystery as to what had caused the belt to fade, the most likely explanation was that it was linked to storm activity that preceded the change.
‘The question now is when will the South Equatorial belt erupt back into activity and reappear?’ Mr Wesley said.
The pattern for this happening is when a brilliant white spot forms in the southern zone. Gradually it will start to spout dark blobs of material which will be stretched by Jupiter’s fierce winds into a new belt, and the planet will return to its familiar ‘tyre track’ appearance.
Jupiter will be closest to Earth on September 24, offering stargazers their best chance of seeing it without its stripe.
Posted by Xeno on May 16, 2010
Brazilian paleontologists have found the near complete fossil of a fearsome predator that roamed the Earth before the dinosaurs.
The 22ft long creature, called Prestosuchus chiniquensis, lived some 238million years ago. It belonged to a family of reptiles called thecodonts and had a large, deep skull with serrated teeth and a long tail.
Weighing 900lbs, the carnivores romated Earth during the Triassic Period 250 to 205 million years ago. Dinosaurs came to dominate from 230million years ago up to their extinction 65million years ago.
The well-preserved creature was found by a team from the Lutheran University of Brazil, in the town of Dona Francisca 160miles from Porto Alegre.
‘It is something that we could never imagine – the quality of preservation and the size of the fossils are sensational,’ Professor Da Silva said.
He added: ‘They were amazing predators. This discovery will allow a better understanding of the anatomy of Prestosuchus and will facilitate a more precise reconstruction of the skeleton of the animal.’
It is also the first find that includes a well preserved hind leg, which will help scientists work out how these ancient creatures moved.
The Prestosuchus was first discovered in Brazil in 1938 by a visiting German paleontologist called Friedrich von Huene.
The remains were found in a sedimentary rock formation, which was a lake millions of years ago.
Paleontologists believe that herbivore creatures stopped to drink at the site and were ambushed by carnivores such as the Prestosuchus.
The team will now evaluate the exposed part of the animal over the next two years. They want to keep the creature, which was a close relative of the crocodile, in Brazil.