Scientists Achieve First Part Of Water Splitting, Working To Achieve Second Part

Posted: Feb 29 2016, 2:28pm CST | by , in News | Latest Science News


Water-splitting half-reaction
Photo credit: Lilac Amirav, Technion-Israel Institue of Technology

Considering the fact that water is made up of oxygen and hydrogen (H2O), scientists have been working for a long time to split the oxygen from the hydrogen and then use the results to provide energy that could power cells used for running electronic devices and vehicles.

The researchers from Technion-Israel Institute of Technology in Haifa, Israel, have published a study titled "Perfect Photon-to-Hydrogen Conversion Efficiency" in the journal Nano Letters, detailing their success at achieving the first part of the two-way process and working toward achieving the second part of it.

The first part is known as reduction, and the second part is known as oxidation.

"Our work shows that it is possible to obtain a perfect 100% photon-to-hydrogen production efficiency, under visible light illumination, for the photocatalytic water splitting reduction half-reaction,” Lilac Amirav, one of the researchers. The others are Philip Kalisman and Yifat Nakibli.

“These results shatter the previous benchmarks for all systems, and leave little to no room for improvement for this particular half-reaction. With a stable system and a turnover frequency of 360,000 moles of hydrogen per hour per mole of catalyst, the potential here is real," Amirav added.

Scientists say the three atoms in H2O do not just separate from one another when a H2O molecule splits apart. It requires two separate half-reactions. For the oxidation part, four individual hydrogen atoms are produced along with an O2 molecule which is discarded, and in the reduction part, the four hydrogen atoms are paired up into two H2 molecules by adding electrons, which produces the useful form of hydrogen: H2 gas.

The scientists say they hope to implement their design rules, experience and accumulated knowledge to enable them construct a system that is able to achieve complete water-splitting and genuine solar-to-fuel energy conversion.

According to Amirav, "The photocatalytic hydrogen generation presented here is not yet genuine solar-to-fuel energy conversion, as hole scavengers are still required. CdS is unfortunately not suitable for overall water splitting since prolonged irradiation of its suspensions leads to photocorrosion.

“We have recently demonstrated some breakthrough on this direction as well. The addition of a second co-catalyst, such as IrO2 or Ru, which can scavenge the holes from the semiconductor and mediate their transfer to water, affords CdS-based structures the desired photochemical stability," he said.

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The Author

<a href="/latest_stories/all/all/52" rel="author">Charles I. Omedo</a>
Charles is covering the latest discoveries in science and health as well as new developments in technology. He is the Chief Editor or Intel-News.




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