Artificial Photosynthesis Research Team

CO2-free fuel and CO2 recycling
Learning from Plants to Create Energy for Humans

We research methods for producing chemicals in a highly economically rational way, to spread artificial photosynthesis technologies for converting solar energy into chemical energy.

Artificial Photosynthesis Research Team

Research themes

  • Development of economical hydrogen production technologies based on a photocatalysis-electrolysis hybrid system that combines photocatalytic reactions with a redox mediator such as iron ions
  • Investigation into hydrogen and high-value-added chemical production technologies
    using semiconductor photoelectrodes and electrode catalysts

Concept for social contributions and implementation

We will realize a paradigm shift in the use of solar energy by constructing an artificial photosynthesis facility.

Research Team Leader / Greetings

Prime Senior Researcher (Leader, Artificial Photosynthesis Research Team)

SAYAMA Kazuhiro

I have been involved in research of photocatalysis and artificial photosynthesis for more than 30 years, ever since I studied at college. I am very fortunate as a researcher to be in an environment where I can devote myself to a single field of study. At GZR, we have deployed a system to search for catalyst materials using robotic technology. This is a deeply familiar area to me, though I wish to actively incorporate new research methods.

SAYAMA Kazuhiro



KON Yoshihiro


KANEKO Masanori


MAYUMI Daisuke

Research Assistant


Technical Staff



● Development of artificial photosynthesis technologies (APT) for utilization of enormous solar energy has been investigated to realize CO2-free and sustainable society.

● APT can convert solar energy into chemical energy (H2, organic compounds, valuable chemicals, etc.), mimicking the mechanism of photosynthesis in plants. 

● Highly efficient and economical APT system should be realized using photocatalyst and photoelectrode prepared by simple processes.

Research topics 1: Water splitting into H2 and O2 using photocatalysts

Powdered semiconductor photocatalysts (oxides and non-oxides) for effective decomposition of water into H2 and O2 is developed. The researches are accelerated by using theoretical chemistry and computational chemistry.

Research topics 2:  H2 production on photocatalysis-electrolysis hybrid system

“Photocatalysis-electrolysis hybrid system” is AIST original technology, and low-cost H2 production with solar energy can be realized by the combination of large photocatalysis pool and low-bias water electrolysis using Fe3+/Fe2+ ion redox mediator.

Research topics 3: Photo-electrochemical process for production of H2 and valuable chemicals to improve economical efficiency

High-value-added chemicals (hydrogen peroxide, hypochlorous acid, etc.) can be produced on oxide photoelectrodes using solar energy, with producing H2 on the counter electrode. These chemicals can be used for sterilizing, bleaching, cleaning, etc. The product selectivities can be ~100% by AIST technology.

Future plan

・ Proposing of innovative systems with economic rationality and reduction of CO2 emission effect by the fusion of artificial and natural photosynthesis.

 ・ Development of high-throughput screening system for materials on photocatalyst and photoelectrode. Utilization of machine learning for big data as research DX.



Kusama, H.; Tokudome, H.; Okunaka, S., Effects of an N-hydroxyimide mediator on the visible-light-induced oxidation of toluene over the bismuth vanadate photocatalyst, J. Photochem. Photobiol. A: Chem. 2023, 444, 115001, 10.1016/j.jphotochem.2023.115001

Published JUL 04 2023

Selected as a HOT article by Energy & Environmental Science

Seki, K.; Miura, T.; Ikoma, T., Origin of the Delayed Fluorescence by Triplet–Triplet Annihilation in Solids with a Power Law Exponent of between -1/2 and -1, J. Phys. Chem. C 2023, 127, 9562-9572, 10.1021/acs.jpcc.3c02128

Published MAY 10 2023

Okunaka, S.; Kameshige, H.; Oozu, S.; Sayama, K.; Tokudome, H. , Effect of polymer additives on photocatalytic and photoelectrochemical properties of BiVO4 prepared from aqueous metal-chelate solution, Jpn. J. Appl. Phys. 2023, 62, SK1030, 10.35848/1347-4065/acc952

Published MAY 04 2023