Molecular design of benzothiadiazole-based dyes for working with carbon nanotube photocatalysts

Abstract

A donor–acceptor–donor (D–A–D) dye consisting of ferrocene units (donors) and a benzothiadiazole unit (acceptor) was synthesized to use the photosensitizer for hydrogen evolution reaction (HER) from water within semiconducting single-walled carbon nanotube (s-SWCNT). The dye was easily encapsulated into s-SWCNT by a solution method to form dye-encapsulated s-SWCNTs (dye@SWCNTs). Subsequently, physical modification of dye@SWCNTs by a fullerodendron gave dye@SWCNT/fullerodendron nanohybrids having dye/s-SWCNT/C₆₀ coaxial heterojunction. Interestingly, dye@SWCNT/fullerodendron nanohybrids act as the photosensitizer for HER in the presence of sacrificial donor, electron relay, and co-catalyst due to the mobile carrier generation upon photoexcitation of the dye molecules.

Graphical Abstract

Keywords:

• Benzothiadiazole
• thiocarbonyl
• carbon nanotube
• photosensitizer
• water splitting

Acknowledgments

This work was partially supported by JSPS KAKENHI grants 15H03519 (Y. T.) and 16K05895 (T. T.).