RMIT researchers have created a new solar paint that absorbs moisture from the air and uses sunlight to split water atoms and harvest hydrogen as fuel.

The paint is a mix of titanium oxide, a common white pigment in wall paints, and a new material, synthetic molybdenum-sulphide, that acts like a silica gel sachet in the way it absorbs moisture.

But the new material also acts as a semi-conductor to catalyse the splitting of water into hydrogen and oxygen molecules, said RMIT lead researcher Dr Kourosh Kalantar-zadeh.

"Basically we are talking about producing fuel from the sun and water vapour in the air," he said. "It is a super simple idea that we have implemented very successfully. It can rival the photovoltaic cells we put on the roof."

He said hydrogen was the cleanest source of energy and could be used in fuel cells as well as conventional combustion engines as an alternative to fossil fuels.

His colleague, Dr Torben Daeneke said the solar paint was an attractive alternative as it required cheap materials, was easy to apply, and could transform everyday surfaces into energy-harvesting, fuel-producing real estate. 

"Our new development has a big range of advantages," Dr Daeneke said. "There's no need for clean or filtered water to feed the system. Any place that has water vapour in the air, even remote areas far from water, can produce fuel."

Dr Kalantar-zadeh added humidity was the key factor but the system worked in dry and hot climates near oceans without trouble.

The initial research published in the American Chemical Society's journal ACS Nano, proved the concept.

"What we have developed is the component that creates the fuel and converts the energy into hydrogen gas," Dr Daeneke said.

"For the final product we would need to incorporate this paint with membranes that are commercially available to harvest the hydrogen selectively and store it as gas for example."

The RMIT research team has released the findings to the public domain, rather than patent it, so the design can be improved upon by the scientific community and fast-tracked for commercial use.

Dr Kalantar-zadeh said he hoped to see solar paint on city buildings and in the suburbs within years. 

"People need such technology," he said.  "We can sit on it for years and years and go through commercialisation by ourselves, but like this I hope we are doing a favour to the community."