Solar Water-Splitting Could Become New Renewable Energy Source

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Written By: Emma Websdale

Hopes for a new clean and renewable source of energy have risen after researchers from the University of Houston split water into hydrogen and oxygen using nanoparticles.

452038535University of Houston research, recently published in the journal Nature Nanotechnology, paves the way for a potential new source of renewable energy, as scientists use cobalt oxide nanoparticles as a catalyst to split water into hydrogen and oxygen.

Although photocatalytic water-splitting experiments have been performed since the 1970s, this is the first time scientists have used cobalt oxide and neutral water under visible light at a high-energy conversion efficiency without the use of sacrificial chemicals (highly active chemicals that are used to prevent a less active material surface from corroding).

The researchers, including scientists from the Institute of Energy Technology (INTE) of the Universitat Politècnica de Catalunya BarcelonaTech (UPC), the University of Auckland, and the King Abdullah University of Science and Technology in Saudi Arabia, have developed a highly active catalyst power that has fused the optical properties of three-dimensional photonic crystals and 2-3 nanometer gold nanoparticles. By harnessing the properties of these crystals and precious-metal nanoparticles, scientists can separate the water into hydrogen and oxygen almost immediately. The scientists report that the new photocatalyst produces more hydrogen than any other method developed so far.

Hosting great potential for renewable energy, this method was also tested by researchers at UPC, who managed to produce 0.025 liters of hydrogen in one hour using one gram of catalyst. Calculations based on eight hours of sunlight daily indicate that an estimated area of 10 X 10 kilometers would be required to produce hydrogen on an industrial scale.

Compared to conventional plants that run on fossil fuels at 800°C, the new photocatalyst system can operate at room temperature. By using solar energy, it can produce hydrogen using 100% renewable energy.

Although the new catalyst brings hope for a new renewable source, Jiming Bao, lead author of the paper and an assistant professor in the Department of Electrical and Computer Engineering at the University of Houston, says that further investigations into improved conversion rate are required for the technology to become commercially viable. Other unresolved issues include reductions in the technology’s cost and extending the lifespan of cobalt oxide nanoparticles.