The effects of Pt cocatalyst particle size on charge transfer kinetics in dye-sensitized SrTiO3 photocatalysts for hydrogen evolution studied by time-resolved emission/absorption spectroscopy

• Published in: Applied catalysis. A, General Vol. 654; no. C; p. 119086
• Main Authors: Nishioka, Shunta, Hojo, Koya, Saito, Daiki, Yamamoto, Issei, Mallouk, Thomas E., Maeda, Kazuhiko
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.03.2023; Elsevier
• Subjects: Dye-sensitized photocatalysts; Hydrogen production; Laser flash photolysis; Metal nanoparticles; Metal nanoparticles; Dye-sensitized photocatalysts; Laser flash photolysis; Hydrogen production
• ISSN: 0926-860X; 1873-3875
• DOI: 10.1016/j.apcata.2023.119086

Dye-sensitized H2 evolution systems were constructed from Pt-loaded SrTiO3 and Ru(II) complex photosensitizers as building blocks, and the impact of the Pt cocatalyst was investigated. In the presence of a stronger electron donor (sodium ascorbate), SrTiO3 loaded with larger Pt particles showed higher activity. On the other hand, the sample having smaller Pt particles gave higher activity in the presence of a weaker electron donor (ethylenediaminetetraacetic acid disodium salt dihydrate). Time-resolved emission/absorption measurements revealed that the larger Pt particles facilitated electron injection from the excited Ru sensitizer to Pt/SrTiO3, while the smaller one improved charge carrier separation by suppressing the back electron transfer reaction from Pt/SrTiO3 to the oxidized sensitizer. These results show that the cocatalyst particle size can affect the kinetics of the electron injection and carrier separation processes. Judicious choice of the Pt particle size can therefore improve the H2 evolution activity in accordance with the reaction system. [Display omitted] •The size of Pt particles on SrTiO3 was controlled by changing the number of photodeposition steps.•The H2 evolution activity of SrTiO3 sensitized by a Ru(II) complex depended on the Pt particle size and electron donor.•Time-resolved spectroscopy measurements revealed changes in the excited carrier dynamics caused by the Pt particle size.