A team from the UPC and the Catalan Institute of Nanoscience and Nanotechnology (ICN2) has designed an efficient and stable photocatalyst capable of producing hydrogen directly using sunlight. The results are published in the journal Nature Communications.
Hydrogen is essential for that energy transition, as long as it is produced from renewable sources (green hydrogen). It has long been known that electrons in some semiconductors can participate in chemical reactions when illuminated by sunlight.
This is the case with titanium dioxide, a cheap and harmless material that is widely used as a white pigment in paints, plastics, papers, inks and cosmetics. The excited electrons in titanium dioxide are capable of generating hydrogen from the protons in water and organic compounds. However, hydrogen production is very low because the electrons tend to relax rather than react, so the efficiency of the process is too low from a practical point of view.
This limitation can be overcome by bringing titanium dioxide into contact with metal nanoparticles, which act as electron filters, extending the life of the electrons in an excited state so that they can react and produce hydrogen. This allows us to achieve hundreds of times higher yields.
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