Friday, 01 August 2014
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Isis innovation investigates sand-powered fuel cells

A new method that combines silicon and water to produce hydrogen could serve as a source of emergency gas for future fuel cell vehicles.

The technique developed by an Oxford University research team led by chemist John Foord generates hydrogen locally at low temperatures.

Project manager Dr Jamie Ferguson, who is helping commercialise Foord’s work through the university’s spin-out company Isis Innovation, explained combining silicon and water to produce hydrogen has been considered by others before but technical hurdles stood in their way.

Under normal conditions, silicon does not largely react to water. While it initially rapidly reacts, Ferguson said, it stops abruptly as soon as an oxide layer is formed.

Foord and his team were able to overcome this, he said, by developing a new method for grinding silica, otherwise known as sand, into silicon nanopowder. When in this nano-state, it is claimed silicon will readily generate hydrogen when contacted with water at temperatures between 70 and 90 degrees Celsius.

Ferguson said one of the main advantages is the only byproduct is sand, which can be safely disposed or recycled.

In addition to developing a new method for milling sand into silicon nanopowder, Foord’s team also developed a material that encapsulates the silicon nanopowder particles. Ferguson said this was done to shield the particles from the air because the silicon nanopowder is so reactive it could theoretically generate hydrogen with exposure to even minimal amounts of water.

While initially being targeted for emergency supplies of hydrogen or lower power fuel cell applications such as laptops or communication devices, the technology has potential to be scaled up.

Foord and his team view local generation of hydrogen as a more plausible alternative to other methods proposed for fuelling portable hydrogen fuel cells.

While hydrogen is energy rich compared to petroleum on a per-weight basis, it is relatively poor on a volumetric basis. This means in portable fuel cell applications, significant volumes of hydrogen will need to be carried on-board unless high pressure or cryogenic hydrogen storage is used. These methods, however, both have significant energy penalties.

Ferguson said the new Oxford method could be considered as a different way of looking at hydrogen storage, ‘except the hydrogen storage here is the water,’ he added.

Ferguson said the team is now currently open to offers from company to license its technology.


Readers' comments (10)

  • Do you get enough power out to run the grinding machine?
    The raw material harvesting is probably low energy use.Is much energy required to clean the raw material?
    I'm sure that carrying the raw material to the grinder taked less energy than hauling all that oil around the world.
    Sounds like a great idea and the twist to store the H in water is good thinking.
    Keep us informed.
    JEA

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  • There is no need of the storage if you do it on board of the vehicle

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  • The research for production of hydrogen for fuel cell by using silicon nanopowder is remarkable. The whole team of researchers is highly appreciated and expected to exhibit more innovation.

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  • If it is ground on board the vehicle, I wonder if it could incorporated into the breaking system. I know this would not be much use on long motorway journeys, but if might be in urban use.

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  • I suspect that silicon nanopowder is at least as carcinogenic as asbestos, so any grinding operations would need to take place under stringent controls.

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  • There seems to be some confusion in the write up between silicon (a quasi-metal) and silicon oxide/silica, the main constituent of common sand and many more .. see, e.g.:- http://www.mii.org/Minerals/photosil.html

    "Silicon is the second most common element in the Earth's crust, comprising 25.7% of the Earth’s crust by weight…. It is shiny, dark gray with a tint of blue. Silicon, atomic number of 14, is a semi-metallic or metalloid, because it has several of the metallic characteristics.

    Silicon is never found in its natural state, but rather in combination with oxygen as a silicate ion (SiO4) in silica-rich rocks such as obsidian, granite, diorite, and sandstone. Feldspar and quartz are the most significant silicate minerals. Silicon alloys with a variety of metals, including iron, aluminum, copper, nickel, manganese and ferrochromium.

    Silica is processed into two intermediate products- silicon and ferrosilicon. Silicon is known in the ferroalloy and chemical industries as “silicon metal.” The ultra pure form of silicon (>99.99% Si) is distinguished from silicon metal by the term “semiconductor-grade silicon.” The terms “silicon metal” and “silicon” are used interchangeably.

    Silicon is used in ceramics and in making glass. Ferrosilicon is crushed into a variety of forms and sold as bulk metal. Depending on its intended use, it can be mixed with aluminum and calcium. It is a very heavy alloy. When it comes into contact with moist air or water, an explosive chemical reaction occurs in which hydrogen is released. Consequently there are very strict laws about the shipping of ferrosilicon it must be kept perfectly clean and dry. .."

    Some imaginative scientists have suggested the possibility of alien life systems based on silicon instead of carbon.

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  • "Foord and his team were able to overcome this, he said, by developing a new method for grinding silica, otherwise known as sand, into silicon nanopowder."

    Sand is NOT silicon. Sand is silicon dioxide. The sand has to undergo a reduction process to eliminate the oxygen, then a coating process to isolate the silicon from oxygen or water, then an exposure process to water (H2O) where upon it oxidizes by pulling the oxygen from a water molecule and releases a diatomic hydrogen molecule.

    It looks like a lot of energy is needed to reduce the silica (silicon dioxide) to pure silicon and use of a isolating material (environmental contamination, perhaps) to get a bit of pure hydrogen.

    Why not put that energy into pulling carbon dioxide from the atmosphere, reducing the CO2 to carbon, splitting water and adding the hydrogen to the carbon to make a new hydrocarbon? Clean the atmosphere and make a energy dense fuel at the same time. Still takes energy. More energy into the formation of the 'fuel' that the fuel contains according to the 2nd law of thermodynamics. College level Thermodynamics!!

    Perpetual motion machines by other names still are not patentable!

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  • What about the energy to create the silicon, which I assume is gotten by driving the oxygen off of silicon dioxide?

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  • Does this mean you would fuel up with nanosand and water ? Heavy stuff to carry around unless you only need a little bit of it! Disposal of sand byproduct in front of wheels would work great on icy or snow packed roads in Canada but would be a nuisance in summer.

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  • It was the weight of water and silica or silicon that struck me too. The nice thing about petrochemical fuels is the energy density per gram. Still its great to see exploration of alternate methods of obtaining fuel. Just wish the articles were a little more detailed.

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