A two-step photoexcitation system for photocatalytic water splitting into hydrogen and oxygen under visible light irradiation

Ryu Abe

Research output: Chapter in Book/Report/Conference proceedingConference PaperResearchpeer-review


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 (Zscheme) 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 (∼460 nm for H2 evolution and ∼600 nm for O2evolution) from that in conventional water splitting systems (∼460 nm) based on one-step photoexcitation in single semiconductor material.

Original languageEnglish
Title of host publicationSolar Hydrogen and Nanotechnology VI
Publication statusPublished - 2011
Externally publishedYes
EventSolar Hydrogen and Nanotechnology VI - San Diego, CA, United States of America
Duration: 23 Aug 201125 Aug 2011


ConferenceSolar Hydrogen and Nanotechnology VI
CountryUnited States of America
CitySan Diego, CA


  • hydrogen
  • photocatalyst
  • photosynthesis
  • redox couple
  • visible light
  • water splitting
  • z-scheme

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