In line with the depletion of fossil fuels and the environmental problems our planet faces due to their combustion, developing technology for clean energy generation is a topic of global interest. Among the various methods proposed to generate clean energy, photocatalytic water splitting is showing much promise. This method utilizes solar energy to split water (H2O) molecules and obtain dihydrogen (H2). The H2 can then be used as a carbon-free fuel or as raw material in the production of many important chemicals.
Now, a research team led by Kazuhiko Maeda at Tokyo Tech has developed a new photocatalyst consisting of nanoscale metal oxide sheets and a ruthenium dye molecule, which works according to a mechanism similar to dye-sensitized solar cells. While metal oxides that are photocatalytically active for overall water splitting into H2 and O2 have wide band gaps, dye-sensitized oxides can utilize visible light, the main component of sunlight. The new photocatalyst is capable of generating H2 from water with a turnover frequency of 1960 per hour and an external quantum yield of 2.4%.
These results are the highest recorded for dye-sensitized photocatalysts under visible light, bringing Maeda's team a step closer to the goal of artificial photosynthesis -- replicating the natural process of using water and sunlight to sustainably produce energy.
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