Recent progress in photocatalysts for overall water splitting under visible light

Abstract

Photocatalytic overall water splitting promises to enable a sustainable large-scale hydrogen-based energy system using solar light, and great attention has been paid to the development of photocatalysts. It is necessary to develop photocatalysts that function under visible light to utilize sunlight efficiently. We have proposed non-oxide materials as candidates for visible-light-driven photocatalysts for overall water splitting, and this manuscript presents our recent research in photocatalyst development. Some oxynitride photocatalysts, modified with appropriate cocatalysts, showed performance for overall water splitting under visible light irradiation. The modification with cocatalysts drastically improved the efficiency of photocatalytic reactions, indicating the importance of controlling the surface active sites. Two-step excitation systems, known as Z-schemes, can significantly expand the range of light available for water splitting to longer wavelengths.