Dye-sensitized H2 evolution from water facilitated by photoinduced electron transfer between molecules on the inside and the outside of a carbon nanotube

• Published in: Journal of applied physics 2021-01, Vol.129 (1)
• Main Authors: Tajima, Tomoyuki, Yamagami, Masahiro, Sagawa, Ryohei, Miyake, Hideaki, Takaguchi, Yutaka
• Format: Article
• Language: English
• Subjects: Applied physics; Catalysts; Dyes; Electron transfer; Electrons; Encapsulation; Hydrogen evolution; Photocatalysis; Polyvinylpyrrolidone; Relay; Single wall carbon nanotubes
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/5.0026896

Dye-encapsulated single-walled carbon nanotubes (dye@SWCNTs) were physically modified to fabricate a water-dispersible dye@SWCNT/dendrimer hybrid. A photocatalytic H2 evolution reaction that uses this dye@SWCNT hybrid as a particulate photocatalyst was conducted in the presence of an electron-relay molecule [methyl viologen (MV2+)], a co-catalyst [PVP–Pt; poly(vinylpyrrolidone)], and a sacrificial donor [1-benzyl-1,4-dihydronicotinamide]. Photoinduced electron transfer occurs between the encapsulated dye molecule inside the SWCNT and the MV2+ ion outside the SWCNT. This is followed by the relay of the electron to the co-catalyst, which reduces H+ to generate H2. The external quantum yield of the H2 evolution reached a maximum of 8.5% under irradiation with light at 510 nm. Notably, the photoinduced electron transfer between the molecules on the inside and the outside of the SWCNT proceeded smoothly despite the possibility of energy migration from the encapsulated dye to the SWCNT or the possibility of charge recombination.