Article originally published on dailymail in July 20th 2015.
Nanowire technology may allow new types of hydrogen fuel cell for vehicles
- Scientists created a grid of tiny wires of gallium phosphide to split water
- This harnessed the sun's energy to generate hydrogen and oxygen
- They say this can be used to create a fuel cell that could power vehicles
- The new technology is 10 times more efficient than previous solar fuel cells
Solar-powered cars have come a step closer after scientists discovered a way to create compact fuel cells that use the power of the sun to generate hydrogen.
Researchers claim their method has increased the efficiency of using solar cells to split water into its constituent elements – hydrogen and oxygen – by a factor of ten.
They say the technique could finally allow cars and other vehicles to be fitted with solar panels, overcoming problems such as keeping the vehicles running at night.
Rather than powering the car directly, the solar panels could produce hydrogen and oxygen from water to produce a fuel cell that can power the vehicles.
The scientists behind the technology say this could provide a new clean replacement for traditional fossil fuels that they have termed 'solar fuel'.
Professor Erik Bakkers, a nanoscientist at Delft University of Technology in Delft, the Netherlands, who led the work, said: 'Photoelectrochemical hydrogen production from solar energy and water offers a clean and sustainable fuel option for the futureThey also say their approach also uses ten thousands times less of the rare-metal semiconductor used in modern solar panels, gallium phosphide.
'For the nanowires we needed ten thousand less precious gallium phosphide material than in cells with a flat surface.
'That makes these kinds of cells potentially a great deal cheaper.'
Creating hydrogen from solar energy has been possible for some time, but it is extremely inefficient and expensive as the amount of energy produced from solar panels is low.
Most solar cells uses silicon based semiconductors to generate electricity from the sun, more recently gallium phosphide has emerged as a new material.
Some approaches have connected a solar cell to a battery, which stores up the energy until there is sufficient to split the water into hydrogen and oxygen but this makes the technology heavy and impractical for vehicles.
The researchers, whose work is published in the journal Nature Communications, used a grid of tiny wires of gallium phosphide measuring 500 nanometres long and 90 nanometres thick.
The gallium phosphide can convert sunlight into electricity and split the water all in one, producing a solar fuel cell.
Energy can be released from the fuel cell by converting the hydrogen and oxygen back into water, releasing electricity.
This could lead to new compact solar-powered fuel cells that can be used on vehicles.
They found this could be used to directly split the water and could boost the yield of hydrogen by a factor of ten to achieve a record for solar cell electrochemical hydrogen production by converting 2.9 per cent of water into hydrogen.
However, the researchers say they have still some way to go before they can reach the sort of yields that can be obtained using batteries – which can convert 15 per cent of water into hydrogen.
Solar powered vehicles usually rely upon solar panels producing electricity to generate power for the vehicle, but these either need large batteries to keep going after dark or cannot operate at night.
Professor Bakkers said the new approach they had developed could allow solar energy to be 'stored' as hydrogen and oxygen for use even after dark.
He said: 'Gallium phosphide is also able to extract oxygen from the water – so you then actually have a fuel cell in which you can temporarily store your solar energy.
'In short, for a solar fuels future we cannot ignore gallium phosphide any longer.