Scientists one step closer to turning water into fuel

30 Oct 2015

Researchers in the US have investigated a new way to turn water into fuel, developing a method that sees sunlight separating the liquid into hydrogen and oxygen and creating clean, cheap fuel.

There are a handful of mysteries that have really stumped scientists across various fields. The search for dark matter has astronomers all over the globe banging their heads against nearby walls.

Manufacturing gold is another. But turning water to fuel, cheaply, and easily, is up there as one of the biggest challenges we face at the moment.

That might be about to change, though, as two scientists at the University of Chicago and the University of Wisconsin have made an important contribution to the effort.

Their research – published in Nature Communications – offers brand new conceptual tools that could, potentially, lead to a simple, cheap and clean extrapolation of hydrogen from water.

Doing the splits

Giulia Galli and Kyoung-Shin Choi investigated ways in which electrodes used for splitting water absorb solar photons, while at the same time improving the flow of electrons from one electrode to another.

The challenge encountered by splitting water is two-fold. First, the solar spectrum must be at its maximum to get electrons up to a level where they change states. Secondly, they must create a flow of current when they change.

Choi worked out that a specific heated electrode – made of bismuth vanadate, while flowing nitrogen gas over it – meant some of the nitrogen was incorporated into the compound. This meant that photon absorption and electron transport increased.

Now run the numbers

Galli then ran the numbers and realised that nitrogen was doing much more, extracting oxygen from the compound and speeding up the process throughout the split.

What’s key, though, is the nitrogen lowered the energy needed to boot the electrons into shape, meaning more solar energy could be used. Or, rather, the solar energy could achieve more.

“Now we understand what’s going on at the microscopic level,” said Galli to the University of Chicago. “So people can use these concepts in other systems to try to improve their efficiency. These are very general concepts that could also be applied to other materials.”

Turning water into fuel

This image depicts the water-splitting process in a light-sensitive electrode which researchers established in an experimental and computational study – Illustration by Peter Allen

Water car image, via Shutterstock

Gordon Hunt was a journalist with Silicon Republic