Photo-induced enhanced Raman spectroscopy as a probe for photocatalytic surfaces

Sultan Ben-Jaber; Daniel Glass; Thomas Brick; Stefan A Maier; Ivan P Parkin; Emiliano Cortés; William J Peveler; Raúl Quesada-Cabrera

doi:10.1098/rsta.2022.0343

Photo-induced enhanced Raman spectroscopy as a probe for photocatalytic surfaces

Philos Trans A Math Phys Eng Sci. 2023 Oct 30;381(2259):20220343. doi: 10.1098/rsta.2022.0343. Epub 2023 Sep 11.

Authors

Sultan Ben-Jaber^{1

2}, Daniel Glass^{1

3}, Thomas Brick³, Stefan A Maier^{3

4}, Ivan P Parkin¹, Emiliano Cortés^{3

5}, William J Peveler⁶, Raúl Quesada-Cabrera^{1

7}

Affiliations

¹ Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK.
² Department of Science and Forensics, King Fahad Security College, Riyadh, Saudi Arabia.
³ The Blackett Laboratory, Department of Physics, Imperial College London, London SW7 2AZ, UK.
⁴ School of Physics and Astronomy, Monash University, Clayton, Victoria 3800, Australia.
⁵ Chair in Hybrid Nanosystems, Faculty of Physics, Ludwig Maximilians Universität München, 80799 München, Germany.
⁶ School of Chemistry, Joseph Black Building, University of Glasgow, Glasgow G12 8QQ, UK.
⁷ Department of Chemistry, Institute of Environmental Studies and Natural Resources (i-UNAT), Universidad de Las Palmas de Gran Canaria, Campus de Tafira, Las Palmas de GC 35017, Spain.

Abstract

Photo-induced enhanced Raman spectroscopy (PIERS) has emerged as a highly sensitive surface-enhanced Raman spectroscopy (SERS) technique for the detection of ultra-low concentrations of organic molecules. The PIERS mechanism has been largely attributed to UV-induced formation of surface oxygen vacancies (V_o) in semiconductor materials, although alternative interpretations have been suggested. Very recently, PIERS has been proposed as a surface probe for photocatalytic materials, following V_o formation and healing kinetics. This work establishes comparison between PIERS and V_o-induced SERS approaches in defected noble-metal-free titanium dioxide (TiO_2-x) films to further confirm the role of V_o in PIERS. Upon application of three post-treatment methods (namely UV-induction, vacuum annealing and argon etching), correlation of V_o kinetics and distribution could be established. A proposed mechanism and further discussion on PIERS as a probe to explore photocatalytic materials are also presented. This article is part of the theme issue 'Exploring the length scales, timescales and chemistry of challenging materials (Part 2)'.

Keywords: defected titanium dioxide; oxygen vacancies; photo-induced enhanced Raman spectroscopy; photocatalysis; surface-enhanced Raman spectroscopy.