A research group led by Assistant Professor Hiroyuki Takeda of Tokyo Institute of Technology, in collaboration with the National Institute of Advanced Industrial Science and Technology, will irradiate a photocatalyst consisting of a copper complex and a manganese complex with visible light to efficiently recycle carbon dioxide. succeeded in.It is expected that the artificial photosynthesis system will be scaled up as a measure against global warming.
The world's carbon dioxide (CO2) emissions are estimated to be over 300 billion tons per year.The photocatalytic technology that reduces carbon dioxide is called artificial photosynthesis, and if it is put into practical use, it can suppress the atmospheric concentration of CO2, which is a greenhouse gas, and can be a substitute for fossil resources in the future.However, the existing high-performance photocatalysts are not widely used due to the problem of material cost, and the CO2 reduction photocatalysts using base metals have low durability and insufficient efficiency.
This time, the research group has developed a photocatalytic system that combines a luminescent copper complex and a manganese complex, and irradiates it with visible light to convert carbon dioxide into carbon monoxide (CO) and formic acid (HCOOH) at normal temperature and pressure with high efficiency. I succeeded in giving back.The quantum yield, which is the ratio of the number of molecules of the reaction product to the amount of irradiated light, is 57%, and the number of turnovers, which indicates how many times the catalyst has functioned during the reaction, is 1300 or more, which is highly efficient and durable. Is shown.These values are significantly higher than other photocatalysts made of base metals, and are equal to or better than high-efficiency metal complexes made of precious metals such as ruthenium (Ru) and rhenium (Re) and rare metals.
Copper is used as a raw material for electric wires and 2-yen coins, and manganese is used as a positive electrode for dry batteries.This time, it was found that a highly efficient COXNUMX reduction photocatalytic reaction can be promoted even with such abundant and low-cost base metal-only photocatalyst.
In the future, the company plans to improve the function of this new photocatalyst and aim to integrate it with a semiconductor photocatalyst that uses a large amount of inexpensive water present on the earth as a reducing agent.
