Artificial leaves could provide cheap energy

Scientists produced a design concept they hope will make it possible to manufacture fuel by photosynthesis.

If successful, it could help pave the way to a green and cost-efficient ”hydrogen economy”.

Photosynthesis enables plants to use energy from sunlight to convert carbon dioxide and water into organic compounds.

The chemistry involved is complex and has never been reproduced artificially,

Today, a team of Chinese scientists revealed the blueprint of an ”Artificial Inorganic Leaf” (AIL) based on Mother Nature’s own design.

A working version could be used to capture solar energy and use it efficiently to split water into oxygen and hydrogen, its component elements.

”Our results may represent an important first step towards the design of novel artificial solar energy transduction systems based on natural paradigms,” said lead researcher Dr Tongziang Fan, from Shanghai Jiaotong University in Shanghai.

Hydrogen is the ultimate clean fuel, producing nothing but water vapour when burned.

Some motor companies, such as Toyota, have already developed hydrogen-fuelled cars. Fuel cells, which generate electricity from a chemical reaction, also rely on hydrogen.

But the problem with hydrogen is that it is energy-consuming and costly to produce using traditional methods.

The new research was presented today at the annual meeting of the American Chemical Society in San Francisco.

Dr Fan’s team used the leaves of the Chinese plant Anemone vitifolia as a ”template” for the artificial leaf.

The concept employs tiny particles of titanium dioxide, a well known photocatalyst that allows sunlight to drive chemical reactions

DIT scientists winning fight on superbugs

RESEARCHERS at the Dublin Institute of Technology (DIT) have made a major breakthrough in the fight against deadly superbugs.

The researchers have developed a light-activated powder which is effective against lethal bug MRSA.

The anti-bacterial powder, which can be added to paint to cover surfaces in hospitals, prisons and in homes, reduces the need for repeated cleaning using chemicals such as bleach.

Scientists have said that the patented self-sterilising material has the potential to greatly improve hygiene in hospitals and schools.

Dr John Colreavy, centre director of Centre for Research in Engineering Surface Technology (CREST) in DIT, headed the research for the innovative product and explained that the antibacterial properties work once a light is switched on.

“It just doesn’t kill the bugs on the surface but it actually breaks down all of the dead matter until you arrive at carbon dioxide and water,” he said.

“Most hygiene technologies kill the bacteria but the dead matter is a very good foundation for even worse challenges on that surface.

“It’s like a vigilant technology, it kills the bacteria, it works all the time there is light and it removes all the matter from the surface,” he added.

Dr Colreavy explained that current hygiene coatings that use photoactive Titanium dioxide (TiO2) materials have serious limitations as they only work outdoors due to the need for UV light.

“Photocatalytic materials are materials that absorb light and form a sort of charge on the surface,” Dr Colreavy said.

The organic compounds including bacteria and dirt are then broken down by the hydroxyl radical to form water and carbon dioxide.

Another key benefit is that no chemicals or metals are leached during the process, which makes it environmentally friendly, and TiO2 is commonly used in suncream and paints due to its non-toxicity to humans and animals.

“While we don’t say it replaces good hygiene practices, we are saying that it is the second line of defence,” he said.

The product will be launched officially later this year and researchers at DIT aim to have the first product on the market by 2011.

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New Color Pigment is Powered by the Sun

Rockwood Pigments, a leading manufacturer of innovative inorganic pigments and business unit of Rockwood Holdings Inc. (NYSE: ROC – News), announces the introduction of a new generation of iron oxide color pigment fused with functional properties that respond to sunlight to enable surfaces to self-clean, reduce air pollutants and inhibit microbial growth. The new pigment, called Solarox™ (patent-pending), is the first colored pigment of its kind with photo-catalytic properties.

Rockwood Pigments, in collaboration with the University of Turin, world-renowned for its expertise in the field of photo-catalysis, has developed a manufacturing process which merges the coloring power of iron oxide pigments with the photo-catalytic properties of titanium dioxide. The resulting Solarox™ pigment is available in the complete range of yellow, red and black iron oxide color shades that can be blended to create a spectrum of brown, gold, tan and buff color combinations.

“Solarox™ represents a completely new approach in color pigment development as we combine the aesthetic appeal of color with the functional power of photo-catalysis, powered by natural light,” says Rockwood Pigment’s President, Andrew Ross. “Through this development, we believe that we will accelerate the interest in and consumption of construction products with photo-catalytic properties. The initial response from customers reinforces our belief in the ultimate success of this product launch. Solarox™ will revolutionise the way color is used, moving beyond aesthetic appeal to providing a positive benefit to our environment”.

Solarox™ pigments demonstrate the same high-durability, fade-resistance and wide application of standard iron oxides. Tests at the University of Turin have confirmed the powerful photo-catalytic properties of Solarox™ and its suitability for use in construction materials such as concrete masonry, pavers, plaster, stucco, roofing materials, wall renderings and decorative concrete.

Mr. Ross adds “It is easy to adopt Solarox™ technology in traditional concrete products. The concrete product manufacturing process will not be altered. There is no new pigment handling equipment required and no need for product reformulation, other than switching to Solarox™. A customer currently making colored concrete products can easily incorporate the benefits of photo-catalytic properties simply by substituting conventional iron oxide pigments with Solarox™.”

Interest in photo-catalytic properties in construction materials is increasing in response to the desire for environmentally compatible construction materials for new-build projects, refurbishments, renovations and the growing trend towards ‘green’ buildings.

Solarox™ pigments comply with existing industry standards for iron oxides. They are compliant with ASTM and European DIN/ISO standards and classified as non-hazardous.

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For further information on Solarox™ visit www.rockwoodpigments.com.

New technology allows concrete to come clean

A recently completed major renovation of the Sun Life Financial Centre in Waterloo is one of a small, but growing number of projects where special cement has been incorporated so that buildings can harness the sun to self clean and de-pollute themselves.

The financial centre’s concrete “smartcast” roof top pavers were manufactured by Hanson Hardscapes using a unique formula which includes special aggregates and admixtures with TX Active photocatalytic white cement.

First used in 2001 in the construction of a landmark church in Rome, the cement has been used in the construction of several prestigious architectural-style buildings in Europe and has now established a foothold in the North American construction market.

The cement, which contains titanium dioxide, speeds up the natural oxidation process in the concrete, says Dan Schaffer, product manager for Essroc, the North American subsidiary of the Italcementi Group, the developer.

It’s a process known as photocatalysis, in which a substance known as a photocatalyst uses light to expedite the rate of a natural oxidation process, he explains.

“There’s nothing magical about it. Essentially sunlight is being used as a strong agent to oxidate primary pollutants such as sulphur dioxide, VOCs and carbon monoxide.”

The photocatalytic action destroys the various organic air pollutants such as car exhaust fumes, industrial and residential emissions that come in contact with the concrete surface. As a result, buildings can maintain its original appearance, he says.

The cement was used for the first time in the production of the precast panels that form the three distinctive “sails” of Rome’s Dives in Misericordia Church, designed by American architect Richard Meier.

It was created by the Italcementi Group to meet the rigid specifications of the architect and Vatican officials who wanted a church that would maintain its appearance in Rome’s smoggy environment, says Schaffer.

The successful application subsequently led to is use in the building of a police headquarters in Bordeaux France and sparked a major independent technical study on its uses by members of the PICADA PROJECT, a non-profit organization comprised of manufacturers and research testing laboratories, says Schaffer.

It was introduced in North America in 2007 and been used in the construction of approximately 20 buildings such as a 75-foot high- Bell Tower at a college in Georgia. “At that height, keeping the precast panels clean through conventional methods would be difficult and costly,” he says.

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Chemists describe solar energy progress and challenges

Scientists are making progress toward development of an “artificial leaf” that mimics a real leaf’s chemical magic with photosynthesis — but instead converts sunlight and water into a liquid fuel such as methanol for cars and trucks. That is among the conclusions in a newly-available report from top authorities on solar energy who met at the 1st Annual Chemical Sciences and Society Symposium. The gathering launched a new effort to initiate international cooperation and innovative thinking on the global energy challenge.
The three-day symposium, which took place in Germany this past summer, included 30 chemists from China, Germany, Japan, the United Kingdom and the United States. It was organized through a joint effort of the science and technology funding agencies and chemical societies of each country, including the U. S. National Science Foundation and the American Chemical Society (ACS), the world’s largest scientific society. The symposium series was initiated though the ACS Committee on International Activities in order to offer a unique forum whereby global challenges could be tackled in an open, discussion-based setting, fostering innovative solutions to some of the world’s most daunting challenges.

A “white paper” entitled “Powering the World with Sunlight,” describes highlights of the symposium and is available along with related materials here.

“The sun provides more energy to the Earth in an hour than the world consumes in a year,” the report states. “Compare that single hour to the one million years required for the Earth to accumulate the same amount of energy in the form of fossil fuels. Fossil fuels are not a sustainable resource, and we must break our dependence on them. Solar power is among the most promising alternatives.”
The symposium focused on four main topics:
•Mimicking photosynthesis using synthetic materials such as the “artificial leaf”
•Production and use of biofuels as a form of stored solar energy
•Developing innovative, more efficient solar cells
•Storage and distribution of solar energy

Highlights of the symposium include a talk by Kazunari Domen, Ph.D., of the University of Tokyo in Japan. Domen described current research on developing more efficient and affordable catalysts for producing hydrogen using a new water-splitting technology called “photocatalytic overall water splitting.” The technology uses light-activated nanoparticles, each 1/50,000 the width of a human hair, to convert water to hydrogen. This technique is more efficient and less expensive than current technologies, he said.

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Toward a nanomedicine for brain cancer

In an advance toward better treatments for the most serious form of brain cancer, scientists in Illinois are reporting development of the first nanoparticles that seek out and destroy brain cancer cells without damaging nearby healthy cells. The study is scheduled for the Sept. 9 issue of ACS’ Nano Letters (“A High-Performance Nanobio Photocatalyst for Targeted Brain Cancer Therapy”).

Brain cancer cells like those in this tumor could someday become the target of nanoparticles that in lab experiments seek out and destroy brain cancer cells without harming healthy cells.

Elena Rozhkova and colleagues note the pressing need for new ways to treat the disease, glioblastoma multiforme (GBM), which often causes death within months of diagnosis. Recent studies show that titanium dioxide nanoparticles, a type of light-sensitive material widely used in sunscreens, cosmetics, and even wastewater treatment, can destroy some cancer cells when the chemical is exposed to ultraviolet light. However, scientists have had difficulty getting nanoparticles, each about 1/50,000th the width of a human hair, to target and enter cancer cells while avoiding healthy cells.

The scientists’ solution involves chemically linking titanium dioxide nanoparticles to an antibody that recognizes and attaches to GMB cells. When they exposed cultured human GMB cells to these so-called “nanobio hybrids,” the nanoparticles killed up to 80 percent of the brain cancer cells after 5 minutes of exposure to focused white light. The results suggest that these nanoparticles could become a promising part of brain cancer therapy, when used during surgery, the researchers say.

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TiO2 coating to combat Swine flu

The TouchClean coating is an anatase titanium dioxide-based nano technology photocatalyst which destroys bacteria, spores, viruses, mould, odours and pollutants.

By Mike Pryce

A LEADING manufacturer of door handles is helping businesses, schools and hospitals fight the threat of swine flu with its anti-bacterial coating service.

Dortrend International is based in Stourport-on-Severn and is the only UK distributor of TouchClean.

The anti-bacterial coating has the technology and components to kill and stop the spread of the swine flu virus on surfaces, walls and equipment.

Philip Dean, managing director, said: “It is an extremely worrying time for the region and the country with the spread of swine flu continuing to infect and have such a significant impact on the public, hospitals, schools and businesses.

“Since the outbreak we have been working flat out to supply the health, education and food sectors with a solution which stops the return or outbreak of swine flu for up to 12 months.”

The TouchClean coating is an anatase titanium dioxide-based nano technology photocatalyst which destroys bacteria, spores, viruses, mould, odours and pollutants.

Dortrend International is working with schools, hospitals, GP surgeries, businesses and food preparation factories both in the West Midlands and the UK in a bid to contain and protect against the spread of the H1N1 virus.

The firm’s process also protects against other deadly viruses such as MRSA, SARS, clostridium difficile and E. coli for 10 years.

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