Solar Refineries

Manufacturers are continuously looking for new ways to convert waste carbon dioxide into useful chemicals. These processes require electricity to break the strong double bonds between carbon and oxygen, but using power derived from fossil fuels for this purpose is somewhat self-defeating. So researchers are looking to sunlight-activated catalysts (or photocatalysts) to drive these reactions.

In the past, photocatalysts made from semiconductors have been used; however, these typically need to operate in the ultraviolet (UV) range — which makes up only about 5% of the spectrum — to generate sufficient power. More recently, an emphasis has been placed on developing materials that can harvest energy from the more abundant visible spectrum by carefully engineering the composition and structure of existing catalysts. For example, doping titanium dioxide with nitrogen lowers the amount of energy required to convert carbon dioxide so that the reaction can be driven with natural sunlight rather than more harmful UV light.

Advances like this have the potential to move the chemical industry closer to creating a negative-emissions economy while generating platform molecules for a variety of useful products, including adhesives, foams, floorings and disinfectants.