Last month, I wrote about how scientists (including me) were working on an area known as artificial photosynthesis, whereby solar energy is used to generate hydrogen and oxygen for use as fuels by splitting water molecules. This hydrogen solar fuel would be cheap, clean and sustainable. There are however many challenges that stand in the way of making this commercially viable just yet. One such hurdle is efficiency. However, scientists in Basel have recently devised a new method of optimising the efficiency of the materials used.
When splitting water, both the oxidation and reduction of water to oxygen and hydrogen can be sped up through the use of appropriate catalysts. Finding a catalyst that works alongside a semiconductor material such as titanium (IV) oxide is pretty easy – good old Platinum does the job rather well – however, finding a co-catalyst that can increase the rate of oxidation of water to oxygen and complement the fundamental electronic set-up of these interfacing materials in order to make the system work well is more of a challenge.
Professor Catherine Housecroft and Professor Edwin Constable who both work with the Swiss Federal Laboratories for Materials Science and Technology (known as Empa) have now devised a way of improving the efficiency of artificial photosynthesis by precisely engineering their materials to have the optimal arrangement for the two catalysts to work at their best. Prof. Constable said, “If you don’t do this, it’s like throwing all the different parts of a clock into a bag, giving it a shake and then hoping it will be possible to tell the time.”
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