Activity

　　A research team led by Professor Domen, Division for Supra-Disciplinary Research of RISM, in collaboration with Japan Technological Research Association of Artificial Photosynthetic Chemical Process (ARPChem), The University of Tokyo, National Institute of Advanced Industrial Science and Technology, and Miyazaki University, has developed a semi-transparent photoanode made of a tantalum nitride nanorod photocatalyst that generates oxygen by sunlight-driven water splitting with high efficiency. The team achieved a solar-to-hydrogen energy conversion efficiency of 10%, one of the highest among tantalum nitride-based photoanode systems.

The photoanode developed effectively separates the charge carriers generated by sunlight absorption and drives the oxygen evolution reaction. Its transparent property allows the construction of a tandem cell for water splitting with high solar energy conversion efficiencies.

Research team at Shinshu University, including Prof. Domen and Prof. Hisatomi, analyzed the tantalum nitride photocatalysts and cocatalysts on the surface.

Hydrogen produced using solar energy is expected to be a next-generation green energy with no CO2 emissions. Based on the scientific findings from this research, the team aims to improve the solar energy conversion efficiency with particulate photocatalyst sheets to produce hydrogen in low cost and to achieve the social implementation of hydrogen production using photocatalysts.

　　This achievement is a result of the research commissioned by New Energy and Industrial Technology Development Organization (NEDO). Based on the scientific findings led by this research, the team continues to research in the project of the "Development of Technology for Producing Raw Materials for Plastics Using CO2 and Other Sources", one of the NEDO's Green Innovation Fund Projects. The project aims to improve the solar-to-hydrogen energy conversion efficiency of particulate photocatalyst sheets for more affordable hydrogen production and achieve the social implementation of hydrogen production through photocatalysts.

The results of this research were published online on August 15, 2023(CET) in a scientific journal, Advanced Energy Materials.

Yuiry Pihosh, Vikas, Nandal, Tomohiro, Higashi, Ryota Shoji, Raman Bekarevich, Hiroshi, Nishiyama, Taro Yamada, Valeria Nicolosi, Takashi Hisatomi, Hiroyuki Matsuzaki, Kazuhiko Seki, Kazunari Domen, Tantalum Nitride-Enabled Solar Water Splitting with Efficiency Above 10%, Advanced Energy Materials (2023) https://doi.org/10.1002/aenm.202301327

Image: Developed semi-transparent oxygen-generating photoanode composed of nanorod-shaped tantalum nitride (Ta3N5-NR)