Japan's Tokyo Institute of Technology (Tokyo Tech) had announced the discovery that the surfaces of an inorganic component of cement selectively absorbs and splits carbon dioxide (CO2) molecules at room temperature. Their discovery is expected to offer a new technology to help reduce CO2 emissions -- a major cause of global warming -- and recycle it as a carbon source.

 

It is known that CO2 is chemically stable and cannot be split without high temperature/pressure conditions and/or active reductants, such as hydrogen. Tokyo Tech has studied its unique physical properties since they succeeded in manufacturing C12A7 electride from C12A7, a binary compound in a lime-alumina system. They demonstrated that C12A7 electride surfaces can selectively absorb CO2 molecules at room temperature and that the gas derived from gaseous CO2 is carbon monoxide (CO). The CO2 gas phase can therefore be split into CO molecules and oxygen atoms. CO can then be reused as a carbon source.

 

Oxygen atoms tend to remain on the surface of C12A7, as compared with CO, and this problem would need to be resolved for industrial applications. This issue is likely to be overcome by combining this technology with other chemical reactions that consume oxygen.