(69d) Efficient Photocatalysts for CO2 Reduction

Both the problems of the global warming and shortage of the fossil resources have brought about great interest in photochemical utilization of CO₂ with solar energy.   Efficient photocatalysts for CO₂ reduction must be necessary for development of such an important technology.

We have developed novel types of photocatalytic systems using metal complexes and/or semiconductors as a photocatalyst.   I will focus on the following systems in my presentation.

(1)   Architecture of supramolecular photocatalysts driven with visible light, which can efficiently reduce CO₂ selectively to CO or HCOOH.¹

(2)   Z-scheme type photocatalysts by using hybrids composed with the supramolecular photocatalyst and a semiconductor, which can reduce CO₂ with methanol as an electron donor (Scheme).²

References:  

1. Gholamkhass, B.; Mametsuka, H.; Koike, K.; Tanabe, T.; Furue, M.; Ishitani, O. Inorg. Chem. 2005, 44, 2326; Sato, S.; Koike, K.; Inoue, H.; Ishitani, O. Photochem. Photobiol. Sci. 2007, 6, 454; Koike, K.; Naito, S.; Sato, S.; Tamaki, Y.; Ishitani, O. J Photochem. Photobiol. A: Chem. 2009, 207, 109; Tamaki, Y.; Watanabe, K.; Koike, K.; Inoue, H.; Morimoto, T.; Ishitani, O. Faraday Discuss. 2012, 155, 115; Tamaki, Y.; Morimoto, T.; Koike, K.; Ishitani, O. Proc. Natl. Acad. Sci. USA 2012, 109, 15673; Tamaki, Y.; Koike, K.; Morimoto, T.; Yamazaki, Y.; Ishitani, O. Inorg. Chem. 2013, 52, 11902; Tamaki, Y.; Koike, K.; Morimoto, T.; Ishitani, O. J. Catal. 2013, 304, 22; Nakada, A.; Koike, K.; Nakashima, T.; Morimoto, T.; Ishitani, O. Inorg. Chem. 2015, 54, 1800; Kato, E.; Takeda, H.; Koike, K.; Ohkubo, K.; Ishitani, O. Chemical Science 2015, 6, 3003; Tamaki, Y.; Koike, K.; Morimoto, T.; Yamazaki, Y.; Ishitani, O. Inorg. Chem. 2013, 52, 11902.

2. Sekizawa, K.; Maeda, K.; Domen, K.; Koike, K.; Ishitani, O. J. Am. Chem. Soc. 2013, 135, 4596.