Solar paint that produces hydrogen fuel

RMIT researchers have developed a sunlight-absorbing paint that produces hydrogen fuel from solar energy and moist air.

The paint contains a newly developed compound that acts like silica gel, which is used in sachets to absorb moisture and keep food, medicines and electronics fresh and dry. But unlike silica gel, the new material, synthetic molybdenum-sulfide, also acts as a semiconductor and catalyses the splitting of water atoms into hydrogen and oxygen.

“Titanium oxide is the white pigment that is already commonly used in wall paint, meaning that the simple addition of the new material can convert a brick wall into energy harvesting and fuel production real estate,” said RMIT lead researcher Dr Torben Daeneke.

“Our new development has a big range of advantages,” he 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.”

Daeneke’s colleague, Distinguished Professor Kourosh Kalantar-zadeh, said, “Hydrogen is the cleanest source of energy and could be used in fuel cells as well as conventional combustion engines as an alternative to fossil fuels.

“This system can also be used in very dry but hot climates near oceans. The sea water is evaporated by the hot sunlight and the vapour can then be absorbed to produce fuel.

“This is an extraordinary concept — making fuel from the sun and water vapour in the air.”

The research, titled ‘Surface Water Dependent Properties of Sulfur Rich Molybdenum Sulphides – Electrolyteless Gas Phase Water Splitting’ has been published in ACS Nano, a journal of the American Chemical Society.