Titanium Dioxide is a Serious Molecule

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Titanium dioxide is a common white pigment used in paint, sunscreen, and food colour. But it is as a photocatalyst that TiO2 is likely to truly throw its weight around. TiO2 can -- in the presence of ultraviolet light (in sunlight) -- break down almost any organic material into CO2 and H2O. As a photocatalyst, TiO2 has the potential to detoxify wastewater, split H2O into hydrogen and oxygen, and generate electricity in the presence of light, among other things. And TiO2 is just about as cheap as dirt so it can be used to control odour in kitty litter.

In Japan, they are using TiO2 to make self-cleaning walls and windows.

Photo-catalysts are substances that mediate chemical reactions and are activated by light energy. When organic matter comes into contact with them, it is oxidized at an increased rate and decomposes into water and carbon dioxide. Walls and windows coated with this property are thus enabled to break down any organic dirt that sticks to them.

...in 2007 ECO-TEX [utilized] a painting technique involving three-layers. The undercoat and pigment are applied as usual, but a third layer of transparent titanium oxide is then applied and fixed. This enables the titanium oxide to be fixed on the surface of the paint, enhancing its cleaning power to repel dirt, its durability, and the design potential of the paint.

According to TOTO, coating the outside walls of an average two-story house with ECO-EX has the same cleaning effect as 15 poplar trees, which are known for their air-purifying properties...The dirt-removing effect of these products greatly reduces the time and cost expended in keeping the outside walls of a building clean. _digitaljournal

As reported previously at Al Fin, clothing that incorporates TiO2 would be essentially self-cleaning in terms of organic dirt and stain. Just expose the clothing to the sun and it will self-clean.

TiO2 is a potent photocatalyst, so you probably would not want to inject it into your blood stream. Who knows what reactions would be catalysed? Who knows? An Xu, Yunfei Chai and Tom K. Hei. They studied the effect of TiO2 in mice.

Conclusions: Our results provided novel information that both TiO2 nanoparticles and C60 were taken up by cells and induced kilo-base pair deletion mutations in a transgenic mouse mutation system. The induction of ONOO [peroxynitrite anions] may be a critical signaling event for nanoparticle genotoxicity. _7thSpace

Since most mutations are not helpful to the organism, we will need to be sure that humans do not breathe TiO2 nanoparticles or otherwise take them into the body in large numbers.

Never Wash Another Diaper or Menstrual Rag

Sure, I know that most people use disposable diapers and sanitary napkins or tampons. But now, using new titanium diapers and sanitary rags, they can keep using the same ones over and over. Why? Because the new titanium oxide nanocrystal materials obliterate organic material. You may have read earlier this year about the titanium dioxide nanocrystal-impregnated wool fibers that literally consume red wine stains. But those voracious nanocrystals will not just drink wine. They'll eat or drink virtually any organic material you care to feed them. They positively love colonic bacteria, and bacteria of all kinds.

When exposed to sunlight, these exciting wee crystals will even split water into oxygen and hydrogen. And now, it is becoming much easier and cheaper to create these diminutive crystalline obliterators, thanks to work done in Australia and China.

The new crystals - which are more than five times more effective at splitting water than unmodified anatase - were made by adjusting the crystal structure on the surface of the crystals. These surfaces, known as facets, typically form in the most thermally stable configuration, designated {101}, which contains mostly 6-coordinate titanium atoms.

However, an alternative surface configuration called {001} where most of the titanium atoms are only 5-coordinate, has been found to be far more reactive. 'The high percentage of "unsaturated" titanium atoms in {001} allows stronger interactions with adsorbed molecules, such as water, resulting in a surface that is many times more reactive,' explains Max Lu, the leader of the team at the University of Queensland, Australia.

...The team demonstrated their results by making crystals at a uniform size of about one micrometre. Whereas only a few percent of the facets in naturally-occurring anatase crystals are the more reactive {001} kind, around 50 per cent of the facets in the new crystals are of this type. __RSC__via__NextEnergyNews

So you may actually want to buy two titanium diapers for your next baby. One for it to wear, and the other to filter your home water, and to generate hydrogen for your home and automobile fuel cells.

But you will only need to buy one titanium sanitary napkin or tampon, unless you have multiple menstruating females in your home with synchronised menstrual cycles. Babies are too young to question your judgment when you provide them with hand-me-down, never-washed titanium diapers from earlier siblings. But teenaged daughters can be a bit fastidious about things like that, so be forewarned.

For the cost of one more titanium diaper, you can provide clean air for your household by duct-taping one of the diapers over your central air and heat outlet. Think of it. Clean air, clean water, free hydrogen . . . and endless recyclable nappies. Not a bad deal.

Foam Metals: Lighter than Water and More Uses than You Can Imagine

Scientists are just beginning to find uses for foam metals: metals that are 90% air bubbles, many of which will float on water. One interesting new use was discovered by University of Quebec at Montreal researchers: producing hydrogen from water.

Metafoam Technologies Inc. proudly announces that its metal foam electrodes have yielded promising results for hydrogen production....Metafoam's nickel foams used as porous electrodes in water electrolysis have shown exciting results thanks to their high surface area. Actually, Metafoam's material has reached roughness factors 2 to 25 times higher than standard porous meshes and competing metal foams.____Source__via__NextEnergy

Metal foams can be made to possess a wide range of properties.

Metal foams are a new class of material, as yet imperfectly characterised, but with alluring properties.

They are light and stiff, they have good energy-absorbing characteristics (making them good for crash-protection and packaging) and they have attractive heat-transfer properties (used to cool electronic equipment and as heat exchangers in engines).

Some have open cells (Figure 1), very much like polymer foams but with the characteristics of metals (ductility, electrical conductivity, weld ability, and so forth).

Others have closed cells, like metallic cork.

And they are visually appealing, suggesting use in industrial design.

There are currently some 12 producers marketing a range of metal foams, mostly based on aluminum, but other metals – copper, nickel, stainless steel and titanium – can be foamed and are available on order.

The most promising applications for metal foams appear to be as cores for light-stiff sandwich panels; as stiffeners to inhibit buckling in light shell structures; as energy absorbing units, both inside and outside of motor vehicles and trains; as efficient heat exchanges to cool high powered electronics (by blowing air through the open cells of the aluminum foam, like that of Figure 1, attached to the heat source) and as light cores for shell casting. Several industrial designers have seen potential in exploiting the reflectivity and light-filtering of open cell foams, and the interesting textures of those with closed cells.___Source

The uses for metal foams listed in the above paragraph are clearly already out of date, given the entry of metal foams into the catalysis and electrode business. Many more uses for these interesting materials are waiting to be found.

We at Al Fin have been looking for suitable materials for building "Seasteads"--floating cities on the ocean. Such materials would need to be lightweight but strong, and resistant to corrosive forces common on the sea. It is easy to visualize many areas of seastead construction that might involve the use of closed cell metal foams.

As better forms of molecular manufacturing come on line, we should expect better metal foams, with custom designed surface area ratios, and complex mixes of materials for specific purposes, to be created.

Fuller Spectrum Solar Energy Harvesting: Transparent Window Collectors Capture Ultraviolet End of Spectrum

Full spectrum sunlight ranges from the longer infrared wavelengths to the shorter wavelength ultraviolet. While nano-antennas can capture up to 70% of infrared radiation, a new nano-silicon technology from Octillion (OCTL) can capture between 50% and 60% of ultraviolet energy. When incorporated into windows, such "solar collectors" allow most visible light through, while capturing the energy from the shorter wavelength photons.

Octillion’s NanoPower Window(TM) technology uses silicon nanoparticles that have the potential to convert conventional home, office and industrial glass windows into those capable of converting solar energy into electricity. The silicon nanoparticles are created through a unique electrochemical and ultrasound process that produces identically sized (1 to 4 nanometers in diameter) highly luminescent nanoparticles of silicon that provide varying wavelengths of photoluminescence with high quantum down-conversion efficiency of short wavelengths (50% to 60%).

“Our silicon nanoparticles are the foundation of our NanoPower Windows,” states Mr. Nicholas S. Cucinelli, President and CEO of Octillion Corp. “In fact, independent tests have shown that the same silicon nanoparticles used in Octillion’s NanoPower Window(TM) are also able to enhance the power output of conventional solar cells by up to 70% in the ultraviolet light range and 10% in the visible.

... When thin films of silicon nanoparticles are deposited (sprayed) onto silicon substrates, ultraviolet light is absorbed and converted into electrical current. With appropriate connections, the films act as nanosilicon photovoltaic solar cells that convert solar radiation to electrical energy.

Source

H/T and Image Credit to Next Energy News

One can easily see how the Octillion technology would complement both conventional PV and nano-antenna solar energy. Clearly, the convergence of nano-technology and solar energy is creating a huge opportunity for renewable energy.

Update: Click on "Read More" below for information about another nano-solar approach to extend the spectrum of PV.

Combining doped thin film metal oxide nano-particles with nano quantum dot crystals, gives a potentially much more efficient PV system.

Two nanotech methods for engineering solar cell materials have shown particular promise. One uses thin films of metal oxide nanoparticles, such as titanium dioxide, doped with other elements, such as nitrogen. Another strategy employs quantum dots--nanosize crystals--that strongly absorb visible light. These tiny semiconductors inject electrons into a metal oxide film, or "sensitize" it, to increase solar energy conversion. Both doping and quantum dot sensitization extend the visible light absorption of the metal oxide materials.

Combining these two approaches appears to yield better solar cell materials than either one alone does, according to Jin Zhang, professor of chemistry at the University of California, Santa Cruz. Zhang led a team of researchers from California, Mexico, and China that created a thin film doped with nitrogen and sensitized with quantum dots. When tested, the new nanocomposite material performed better than predicted--as if the functioning of the whole material was greater than the sum of its two individual components. ... The resulting hybrid material offered a combination of advantages. Nitrogen doping allowed the material to absorb a broad range of light energy, including energy from the visible region of the electromagnetic spectrum. The quantum dots also enhanced visible light absorption and boosted the photocurrent and power conversion of the material.

When compared with materials that were just doped with nitrogen or just embedded with cadmium selenide quantum dots, the nanocomposite showed higher performance, as measured by the "incident photon to current conversion efficiency" (IPCE), the team reported. The nanocomposite's IPCE was as much as three times greater than the sum of the IPCEs for the two other materials, Zhang said.

Physorg

Breakthroughs in Solar Cell Technology from Australia and South Africa

Photovoltaic solar cells are poised for much greater utilisation, worldwide. According to The Energy Blog, the costs of solar power will be cut in half by 2010, and cost comparable to nuclear energy by no later than 2030.

News reports from researchers in Australia and South Africa suggest that the price reductions may even occur sooner than the predictions of mainstream energy analysts suggest. At the University of Queensland, plastics and nanotech crystals are replacing the silicon in the solar cells--greatly reducing potential production costs.

UQ Master of Physics student Michael Deceglie is working on improving the stability and overall efficiency of solar cells.

Mr Deceglie is testing two new ways of making solar cells out of dye-sensitized solar cell and a combined nanocrystal polymer solar cell.

The dye-sensitized cells use dye molecules to inject electrons into a thin titanium dioxide film while the polymer cell is a thin film of plastic mixed with microscopic crystals that channel the charge through the cell.

Mr Deceglie said both methods could produce solar cells that had similar efficiencies to current silicon technology but were cheaper more flexible, easier to produce and more environmentally friendly.

“Since electrons don't move well in the polymers, we incorporate nanocrystals with the polymer to provide a pathway along which electrons can move to generate electrical current,” Mr Deceglie said.

“The dye-sensitzed device works in a manner similar to phosynthesis in plants.”

Source.

South African researchers have developed another alternative approach to photovoltaic solar cells, using a unique metal alloy in flexible, very thin layers.

In a scientific breakthrough that has stunned the world, a team of South African scientists, led by Professor Vivian Alberts, has developed a revolutionary new, highly efficient solar power technology” and “The South African solar panels consist of a thin layer of a unique metal alloy that converts light into energy.”

The photo-responsive alloy can operate on virtually all flexible surfaces. The new panels are approximately five microns thick (a human hair is 20 microns thick) while the older silicon panels are 350 microns thick. Alberts claims the cost of the South African technology is a fraction of the cost for less effective silicon solar panels.”

This claim is corroborated in today’s story in the South Africa Mining Weekly, where alongside the report about Eskom’s solar thermal project there is this: “The University of Johannesburg’s Professor Vivian Alberts, from the department of physics, has developed solar panels that may just take this technology further into the main-stream, owing to the cost reductions he has achieved.

Alberts’ invention is five micro-metres thick, combining several semiconductor materials which are as effective, if not more so, than silicon. As it uses no silicon, costs are dramatically lower. It makes use of normal window glass as a substrate, with molybdenum applied as back contact, followed by the core component, being a compound semiconductor comprising five elements - copper, indium, gallium, selenium and sulphide, replacing the silicon - with cadmium sulphide as a buffer layer, followed by an intrinsic zinc oxide layer and, finally, a conductive zinc-oxide layer. The most expensive part of the panel is the glass,” said Alberts.

Source.

Hat tips to keelynet.com and what's next in scitech.

The high cost of solar cell grade silicon has driven the production costs of photovoltaics upward. But scientists and engineers are always looking for ways to improve technology, to get around the roadblocks to economic utilisation. See this Energy Blog article for information about a new silicon feedstock for photovoltaics.

When eminent scientists predict that something is impossible, they are almost certainly wrong. Thomas Kuhn merely reminded us of something that young innovators have known throughout human history--sometimes the older scientists with vested interests in the old ways of thinking have to die off, before humans can move on.