“…Take sunlight, add water, and there you have it: free energy.
Plants have been doing this for quite some time, splitting water’s hydrogen apart from its oxygen …
… but our efforts to turn water into a source of free hydrogen fuel by mimicking them have borne no fruit.
The problem is that splitting water takes more energy than conventional solar-cell technology can realistically deliver.
But now we may be tantalisingly close to having economically viable sun-powered water splitters …
…and with it all the clean-burning fuel we want.
In 2008, Daniel Nocera at the Massachusetts Institute of Technology and his team unveiled a revolutionary approach to splitting water.
They used a cheap cobalt-phosphate catalyst and titanium oxide electrodes that need far less electricity than conventional electrolysis to split water.
That raised the possibility of stealing plants’ trick and using sunlight to power the reaction.
However, the number of photovoltaic cells needed for such devices mean it cannot compete on price with fossil fuels, says Daniel Gamelin, a chemist at the University of Washington in Seattle.
But Gamelin and his team thought they could bring down the costs by incorporating some of that photovoltaic technology in Nocera’s water-splitting device …
… creating a so-called photoelectrochemical (PEC) water splitter…”
go to source/story>>>Green machine: Perfecting the plant way to power – tech – 01 September 2010 – New Scientist
