Ishitani has been interested in artificial photosynthesis for a long time.
His group has developed molecular technology for metal-complex photocatalysts for CO2 reduction and hybridized them with various semiconductor materials. He recently succeeded to construct Z-scheme photocatalytic systems which efficiently reduce CO2 by using water as a reductant and visible light as an energy source, and photocatalytic and electrocatalytic systems for direct reduction of low concentration CO2.
Artificial photosynthesis will be a key technology for human beings, whereas the basic studies, such as photochemistry of metal complexes and semiconductors and photofunctional chemistry, have not been developed sufficiently. His group is trying to solve the following problems: (1) creation of photocatalytic metal complexes for transforming solar energy to chemical energy, (2) artificial systems expressing the similar function to nature photosynthesis, and (3) establishment of strategy and synthetic methods for metal complexes controlling the transfer of photon or electrons.
The Japanese Photochemistry Association Award, the Japanese Photochemistry Association, 2007
Commendation for Science and Technology, the Minister of Education, Culture, Sports, Science and Technology, Japan, 2017
Koike, K., D.C. Grills, Y. Tamaki, E. Fujita, K. Okubo, Y. Yamazaki, M. Saigo, T. Mukuta, K. Onda and O. Ishitani. "Investigation of excited state, reductive quenching, and intramolecular electron transfer of Ru(II)-Re(I) supramolecular photocatalysts for CO2 reduction using time-resolved IR measurements." Chem. Sci. 9 (2018): 2961-2974.
Cometto, C., R. Kuriki, L. Chen, K. Maeda, T-C. Lau, O. Ishitani and M. Robert "A Carbon Nitride/Fe Quaterpyridine Catalytic System for Photostimulated CO2-to-CO Conversion with Visible Light." J. Am. Chem. Soc. 140 (2018): 7437-7440.
Kumagai, H., G. Sahara, K. Maeda, M. Higashi, R. Abe and O. Ishitani. "Hybrid photocathode consisting of a CuGaO2 p-type semiconductor and a Ru(II)–Re(I) supramolecular photocatalyst: non-biased visible-light-driven CO2 reduction with water oxidation." Chem. Sci. 8 (2017): 4242-4249.
Nakajima, T., Y. Tamaki, K. Ueno, E. Kato, T. Nishikawa, K. Ohkubo, Y. Yamazaki, T. Morimoto and O. Ishitani. "Photocatalytic Reduction of Low Concentration of CO2." J. Am. Chem. Soc. 138 (2016): 13818-13821.
Morimoto, T., C. Nishiura, M. Tanaka, J. Rohacova, Y. Nakagawa, Y. Funada, K. Koike, Y. Yamamoto, S. Shishido, T. Kojima, T. Saeki, T. Ozeki and O. Ishitani. "Ring-Shaped Re(I) Multinuclear Complexes with Unique Photofunctional Properties." J. Am. Chem. Soc. 135 (2013): 13266-13269.