Jul 07 2022

Expectations are rising for green hydrogen production through water electrolysis¹ using electricity derived from sunlight to move toward realizing a sustainable carbon-neutral society. It is essential to develop a highly-efficient water electrolysis cell² that operates at low overvoltage³ and combine it with a solar cell appropriate for its maximum output to achieve high solar-to-hydrogen efficiency (STH)⁴. The research group of TSUBONOUCHI Yuta (Specially Appointed Assistant Professor), ZAKI NABEIH AHMED Zahran (Specially Appointed Associate Professor) and Professor YAGI Masayuki of the Department of Materials Science and Technology, Faculty of Engineering, Niigata University collaborated with the research group of Dr. SAYAMA Kazuhiro, Dr. SUGAYA Takeyoshi, Dr. MISEKI Yugo and Dr. MAKITA Kikuo of the Global Zero Emission Research Center (GZR) in the National Institute of Advanced Industrial Science and Technology (AIST) have developed a green hydrogen production system through solar water splitting using a highly-efficient water electrolysis cell and a solar cell, demonstrating that hydrogen can be produced stably for one month with the world's highest level of STH (13.9%).

Research Results

• Succeeded in developing a highly-efficient water electrolysis cell that operates at low overvoltage.
• Developed solar water splitting that uses a highly-efficient water electrolysis cell and a solar cell.
• Demonstrated stable water production with the world's highest solar-to hydrogen efficiency (13.9%).

Glossary

1. Water electrolysis: A technology that uses electrical energy to split water into oxygen and hydrogen in order to produce hydrogen.
2. Water electrolysis cell: An electrolytic tank for electrolyzing water.
3. Overvoltage: The difference between the voltage required to actually cause the reaction and the theoretical voltage of the reaction. The lower this value, the more efficient the water electrolysis cell.
4. Solar-to-hydrogen efficiency (STH): The efficiency at which solar energy is converted into hydrogen energy.

Publication Details

Journal: ACS Applied Energy Materials
Title: Perfect Matching Factor between a Customized Double-Junction GaAs Photovoltaic Device and an Electrolyzer for Efficient Solar Water Splitting
Authors: Zaki N. Zahran, Yugo Miseki, Eman A. Mohamed, Yuta Tsubonouchi, Kikuo Makita, Takeyoshi Sugaya, Kazuhiro Sayama, Masayuki Yagi
DOI: 10.1021/acsaem.2c00768