24-12-2012, 11:02 PM
University of Pennsylvania (USA) tested an experimental device, which may be a prototype of a new type of solar power plants. Usually in such stations are either semiconductors or system for direct heating of sunlight gases or liquids, which are then set in motion the heat engines, rotating electrical generators. device, which was invented by Professor Thomas Mallouk and his fellow converts sunlight into electricity using a chemical process.
In this case, it is not only a source of electrical current, but also decomposes water into oxygen and hydrogen. This new device mimics the action of photosynthesis systems with which nature has endowed many plants and even bacteria - though still with a very low efficiency. Like all electrochemical generators, it has two electrodes immersed in an electrolyte - in this case, an aqueous solution of common salt . The negative electrode, the cathode is made of pure platinum. The design of the anode, the positive electrode, is much more complicated.
It is made out of titanium dioxide and coated organic pigment mixed with iridium oxide. Blue pigment absorbs sunlight, which are much more energy than red, yellow or green. Solar rays knock out of its molecules, free electrons that enter into reactions that lead to the dissociation of water into hydrogen and oxygen. These reactions occur only in the presence of a catalyst, which serves as iridium oxide. However, in its current form, the new generator can not decompose water without assistance. This gives a little less voltage volts, while for the dissociation of water takes about a quarter volts. So it produces oxygen and hydrogen only when it is connected to an external source, which gives boost.
In addition, its efficiency is less than three tenths of one percent - is ten times lower than that of the natural systems of photosynthesis. However, the developers believe that the elimination of these difficulties - a trick. February 18, they informed about their results at delegates met in Boston annual meeting of the American Society in support of science.
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