[15p-A24-1~10] Materials and Physics of Solar-Hydrogen Production Catalysts

[15p-A24-4] Z-scheme type photocatalysis systems for visible light induced water splitting

〇Ryu Abe¹ (1.Kyoto Univ.)

Keywords:semiconductor photocatalyst, solar hydrogen production, visible light

Photocatalytic water splitting using semiconductor materials has attracted considerable interest due to its potential for clean production of H₂ from water by utilizing abundant solar light. The developments of water-splitting systems that can efficiently use visible light have been a major challenge for many years in order to realize efficient conversion of solar light. We have developed a new type of photocatalysis system that can split water into H₂ and O₂ under visible light irradiation, which was inspired by the two-step photoexcitation (Z-scheme) mechanism of natural photosynthesis in green plants. In this system, the water splitting reaction is broken up into two stages: one for H₂ evolution and the other for O₂ evolution; these are combined by using a shuttle redox couple (Red/Ox) in the solution. The introduction of a Z-scheme mechanism reduces the energy required to drive each photocatalysis process, extending the usable wavelengths significantly from that in conventional water splitting systems based on one-step photoexcitation in single semiconductor material. In this presentation, the basic concept of Z-scheme water splitting, as well as newly-developed materials for, will be introduced.