Ultrafast Surface-Specific Spectroscopy of Water at a Photoexcited TiO2 Model Water-Splitting Photocatalyst

© 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH..

A critical step in photocatalytic water dissociation is the hole-mediated oxidation reaction. Molecular-level insights into the mechanism of this complex reaction under realistic conditions with high temporal resolution are highly desirable. Here, we use femtosecond time-resolved, surface-specific vibrational sum frequency generation spectroscopy to study the photo-induced reaction directly at the interface of the photocatalyst TiO2 in contact with liquid water at room temperature. Thanks to the inherent surface specificity of the spectroscopic method, we can follow the reaction of solely the interfacial water molecules directly at the interface at timescales on which the reaction takes place. Following the generation of holes at the surface immediately after photoexcitation of the catalyst with UV light, water dissociation occurs on a sub-20 ps timescale. The reaction mechanism is similar at pH 3 and 11. In both cases, we observe the conversion of H2 O into Ti-OH groups and the deprotonation of pre-existing Ti-OH groups. This study provides unique experimental insights into the early steps of the photo-induced dissociation processes at the photocatalyst-water interface, relevant to the design of improved photocatalysts.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:63

Enthalten in:

Angewandte Chemie (International ed. in English) - 63(2024), 8 vom: 19. Feb., Seite e202312123

Sprache:

Englisch

Beteiligte Personen:

Backus, Ellen H G [VerfasserIn]
Hosseinpour, Saman [VerfasserIn]
Ramanan, Charusheela [VerfasserIn]
Sun, Shumei [VerfasserIn]
Schlegel, Simon J [VerfasserIn]
Zelenka, Moritz [VerfasserIn]
Jia, Xiaoyu [VerfasserIn]
Gebhard, Maximilian [VerfasserIn]
Devi, Anjana [VerfasserIn]
Wang, Hai I [VerfasserIn]
Bonn, Mischa [VerfasserIn]

Links:

Volltext

Themen:

Interface
Journal Article
Photocatalyst
Sum Frequency Generation
Time-Resolved Spectroscopy
Titanium Dioxide

Anmerkungen:

Date Revised 12.02.2024

published: Print-Electronic

Citation Status PubMed-not-MEDLINE

doi:

10.1002/anie.202312123

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM365020745