Hydrogen is one of the cleanest fuels around, turning into water when it is burned. However, common methods to harvest hydrogen are not so clean as they involve fossil fuels, or are not cost effective. Researchers at the RMIT University in Australia have developed a new kind of photocatalytic paint material that is able to absorb water vapour from the air and split it to generate hydrogen.

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-sulphide, also acts as a semi-conductor and catalyses the splitting of water atoms into hydrogen and oxygen.

When mixed with titanium oxide particles, the new compound becomes a sunlight-absorbing material that produces hydrogen fuel from solar energy and moist air.

Titanium oxide is already widely used as the white pigment in wall paint. With the addition of the new material, a simple brick wall can become an energy harvesting and fuel production real estate.

The new photocatalytic paint has various advantages. There is no need to use clean or filtered water, as opposed to traditional methods to make hydrogen. Anywhere that has water vapour in the air can produce fuel, including, for instance, in hot but dry climates near the ocean. The seawater evaporates and can be turned into hydrogen.

While the idea is great, of course, as we are in desperate need of clean energy and lots of it, the researchers do not say anything about how the hydrogen is captured and stored, and thus can be used. Perhaps that will be the next step in the research.

Photos: Pexels / Daniel Case / Shakko / NASA / Lauren Harnett