American scientists are investigating ways of harnessing the properties of ruthenium in order to produce clean hydrogen energy more efficiently.

Researchers from Virginia Polytechnic and State University say that decades of work in the field are now starting to yield results, as they develop catalysts which can use the sun's energy to extract hydrogen from water.

By developing a large molecule, or 'supramolecular complex', the team have sought to create the most efficient means for taking energy from the largest part of the sunlight's spectrum.

This molecule is composed of elements including rhodium, ruthenium, chlorine, carbon, nitrogen and hydrogen.

The materials are said to be the ideal combination to absorb the maximum level of energy from photons, with the supramolecular complex being used to separate hydrogen gas from water.

Karen Brewer, an associate professor of chemistry at Virginia Tech, explained to Technology Research News: "The hydrogen gas would then be used as a fuel and combusted in the presence of oxygen in air to produce water and energy, either in the form of heat for a combustion engine or electricity from a fuel cell."

Ms Brewer said that the team had "worked for many years on trying to understand the properties of these supramolecular complexes well enough".

"Understanding the interactions of light with complex molecular systems could have broad impact in a variety of processes that involve light energy," she added.

Now the researchers say they are working on ways in which they can incorporate the technology into applications, and how to tweak the efficiency of the process.