The technology that’ll rival solar-powered electricity
Competition could be coming to solar-powered fuel, with new and inexpensive materials nearing the market.
Research published last week in the journal Science has provided the latest boost to the promise of solar-power hydrogen fuel, which could offer power vehicles at a fraction of the cost currently needed.
Kyoung-Shin Choi, the chemistry professor who led the study, said: “In order to make commercially viable devices for solar fuel production, the material and the processing costs should be reduced significantly while achieving a high solar-to-fuel conversion efficiency”, reports Phys.org.
Several big car manufacturers, including Toyota and Nissan, are focusing their energies on commercially producing hydrogen vehicles.
Hydrogen fuel cell buses were introduced in London in 2011, releasing nothing except water into their air.
But currently, solar fuel production isn't really an option. The cost of using the most efficient materials to make sun-capturing semiconductors and catalysts to generate fuel is far too high to compete with petrol.
But Choi and her team managed to use oxide-based materials split water into hydrogen and oxygen using solar energy – a small but significant step forward.
They made solar cells from bismuth vanadate – a mixed-metal oxide – employing the same process used to make gold-plated jewellery or the surface coat of car bodies. This upped the surface area of the compound to an astonishing 32 square metre per gram.
Choi said:
Without fancy equipment, high temperature or high pressure, we made a nanoporous semiconductor of very tiny particles that have a high surface area. More surface area means more contact area with water, and, therefore, more efficient water splitting.
A catalyst was then developed, stacking a pair of cheap catalysts to do the job. Neither would work very well individually, but together, they enable a much faster system.
The solar-to-hydrogen conversion efficiency was 1.7 per cent – the highest reported for any oxide-based photoelectrode system.
The highest recorded efficiency for a solar cell producing electricity is 44.7 per cent.
But the research is a move forward, particularly when it comes to cost.
"Combining this cheap catalyst duo with our nanoporous high surface area semiconductor electrode resulted in the construction of an inexpensive all oxide-based photoelectrode system with a record high efficiency," said Choi.
The professor's confident the approach can be applied to identify how other materials can be even more efficient when combined, giving labs across the world a crucial leg up when it comes to moving product development forward.