A team from Australia’s RMIT University created a “solar paint” that generates its own energy. The sunlight-absorbing substance absorbs and splits water atoms, resulting in hydrogen that could someday be used to power fuel cells and conventional combustion engines.

Distinguished Professor Kourosh Kalantar-zadeh (left) and Dr. Torben Daeneke (right).

According to RMIT lead researcher Dr. Torben Daeneke, the paint converts a brick wall into energy-harvesting real estate.

"Any place that has water vapor in the air, even remote areas far from water, can produce fuel,” said Daeneke.

Tech Briefs spoke with Daeneke’s colleague and fellow researcher Distinguished Professor Kourosh Kalantar-zadeh.

Tech Briefs: What is the solar paint made of?

Kourosh Kalantar-zadeh: The solar paint is a mix of molybdenum sulphides and titanium oxides. Molybdenum sulphide, which is polymeric and one dimensional (made of very small-dimension pores), can strongly absorb water moisture. Titanium oxide provides the correct semiconducting mix with molybdenum sulphide for splitting the water into hydrogen and oxygen.

Tech Briefs: How does the solar paint work? How can the walls of a home generate energy?

Kalantar-zadeh: The paint strongly absorbs water molecules from the air, and then uses the Sun’s light energy to split the molecules into oxygen and hydrogen gases. With membranes, we separate the hydrogen gas to be used as a storage energy material (see Figure). The system can adsorb every bit of the water molecules in the air. This water in the air is highly purified and easy to use.

Tech Briefs: Where can the generated energy be used?

Kalantar-zadeh: The hydrogen can be used in combustion heat engines (like the engines of cars) and in fuel cells to produce energy.

Tech Briefs: What are your biggest challenges in getting this solar paint to operate effectively?

A diagram of the RMIT-developed solar paint. (Credit: RMIT)

Kalantar-zadeh: The photo-splitting process needs to be performed at a higher rate to avoid surface saturation. We still need to turn off the system every five minutes to replenish the surface from excess moisture, as the photo-splitting rate is slightly lower than the water absorption. We want to make the system more efficient.

Tech Briefs: How do you envision this technology being used in the future?

Kalantar-zadeh: It will be widespread. It is a technology that can shift the energy economy to a hydrogen economy. This disruptive concept has the potential to change many of the current technologies as we know them.


Read the RMIT Press Release: “Solar Paint Offers Endless Energy from Water Vapour. 

Learn about NASA’s Solar Panel and System Design to Reduce Heating.

Read more Energy tech briefs.