Photocatalytic CO2Reduction Using a Robust Multifunctional Iridium Complex toward the Selective Formation of Formic Acid

Kenji Kamada, Jieun Jung, Taku Wakabayashi, Keita Sekizawa, Shunsuke Sato, Takeshi Morikawa, Shunichi Fukuzumi, Susumu Saito

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A highly efficient tetradentate PNNP-type Ir photocatalyst, Mes-IrPCY2, was developed for the reduction of carbon dioxide. The photocatalyst furnished formic acid (HCO2H) with 87% selectivity together with carbon monoxide to achieve a turnover number of 2560, which is the highest among CO2 reduction photocatalysts without an additional photosensitizer. Mes-IrPCY2 exhibited outstanding photocatalytic CO2 reduction activity in the presence of the sacrificial electron source 1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]imidazole (BIH) in CO2-saturated N,N-dimethylacetamide under irradiation with visible light. The quantum yield was determined to be 49% for the generation of HCO2H and CO. Electron paramagnetic resonance and UV-vis spectroscopy studies of Mes-IrPCY2 with a sacrificial electron donor revealed that the one-electron-reduced species is the key intermediate for the selective formation of HCO2H.

Original languageEnglish
Pages (from-to)10261-10266
Number of pages6
JournalJournal of the American Chemical Society
Issue number23
StatePublished - 10 Jun 2020

Bibliographical note

Funding Information:
We thank Dr. Kin-ichi Oyama (Nagoya University) for elemental analysis. This work was supported by a Grant-in-Aid for Early-Career Scientists (18K14241 to J.J.), a Grant-in-Aid for Scientific Research (B) (19H02713 to S.S.), and a Grant-in-Aid (16H02268 to S.F.) from the Japanese Society for the Promotion of Science (JSPS), by the Asahi Glass Foundation (Step-Up Grant to S.S.), by a Grant-in-Aid for Scientific Research on Innovative Areas (18H04247 to S.S.) from the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT), and by the Ministry of the Environment of the Government of Japan.

Publisher Copyright:
Copyright © 2020 American Chemical Society.


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