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New Photocatalyst Paves Way for Large-scale Artificial Photosynthesis

2019/01/16 14:09
CleanTech Labo
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The newly-developed photocatalyst consisting of Cu complex and Mn complex (source: JST, TI Tech)

A Japanese research group made a photocatalyst consisting of copper (Cu) complex and manganese (Mn) complex and found that it is possible to reduce carbon dioxide (CO2) to carbon monoxide (CO) and formic acid (HCOOH) with a high efficiency by irradiating the photocatalyst with visible light.

This was announced Nov 28, 2018. The group consists of researchers from Tokyo Institute of Technology (TI Tech) and National Institute of Advanced Industrial Science and Technology (AIST).

High-efficiency CO2 reduction photocatalytic reaction had been realized only with photocatalysts using, for example, (1) rhenium (Re), a rare metal that barely exists on the earth, and (2) ruthenium (Ru), a very expensive precious metal. On the other hand, photocatalysts using base metals that are inexpensive and available in large quantities had a low durability and low efficiency.

This time, the research group developed a photocatalyst system combining luminescent Cu complex and Mn complex. The efficiency and durability of the photocatalyst are 57% (quantum yield) and more than 1,300 times (the number of turnovers), respectively, which are far higher than those of conventional catalysts using base metals and equivalent to or higher than high-efficiency catalysts using precious and rare metals.

The research group claims that the latest achievement is the first step toward realizing large-scale artificial photosynthesis. The group aims to improve the functions of the new photocatalyst and combine it with a semiconductor photocatalyst that uses water, which is inexpensive and exists in large quantity on the earth, as a reducing agent.

The development of the new photocatalyst was conducted with help from Core Research for Evolutional Science and Technology (CREST), a project of Japan Science and Technology Agency (JST). The research results were published on the Journal of the American Chemical Society Nov 27, 2018 (local time).

Original Japanese article