Hopes for clean, renewable energy up after water split into oxygen and hydrogen

Washington – Researchers have raised hopes for potentially creating a clean and renewable source of energy after they split water into hydrogen, oxygen by using light, nanoparticles.
The research by the University of Houston involved the use of cobalt oxide nanoparticles to split water into hydrogen and oxygen.

Jiming Bao, lead author of the paper and an assistant professor in the Department of Electrical and Computer Engineering at UH, said that the research found a new photocatalyst and demonstrated the potential of nanotechnology in engineering a material’s property, although more work remains to be done.

Bao said photocatalytic water-splitting experiments have been tried since the 1970s, but this was the first to use cobalt oxide and the first to use neutral water under visible light at a high energy conversion efficiency without co-catalysts or sacrificial chemicals.

Researchers prepared the nanoparticles in two ways, using femtosecond laser ablation and through mechanical ball milling. Despite some differences, Bao said both worked equally well.

Different sources of light were used, ranging from a laser to white light simulating the solar spectrum. He said he would expect the reaction to work equally well using natural sunlight.

Once the nanoparticles are added and light applied, the water separates into hydrogen and oxygen almost immediately, producing twice as much hydrogen as oxygen, as expected from the 2:1 hydrogen to oxygen ratio in H2O water molecules, Bao said.

The experiment has potential as a source of renewable fuel, but at a solar-to-hydrogen efficiency rate of around 5 percent, the conversion rate is still too low to be commercially viable.

The study has been published online in Nature Nanotechnology.