Print Email Facebook Twitter Photophysical Characterization of Ru Nanoclusters on Nanostructured TiO2 by Time-Resolved Photoluminescence Spectroscopy Title Photophysical Characterization of Ru Nanoclusters on Nanostructured TiO2 by Time-Resolved Photoluminescence Spectroscopy Author Wenderich, Kasper (University of Twente) Zhu, Kaijian (University of Twente) Bu, Yibin (University of Twente) Tichelaar, F.D. (TU Delft QN/Afdelingsbureau; Kavli institute of nanoscience Delft) Mul, Guido (University of Twente) Huijser, Annemarie (University of Twente) Date 2023 Abstract Despite the promising performance of Ru nanoparticles or nanoclusters on nanostructured TiO2 in photocatalytic and photothermal reactions, a mechanistic understanding of the photophysics is limited. The aim of this study is to uncover the nature of light-induced processes in Ru/TiO2 and the role of UV versus visible excitation by time-resolved photoluminescence (PL) spectroscopy. The PL at a 267 nm excitation is predominantly due to TiO2, with a minor contribution of the Ru nanoclusters. Relative to TiO2, the PL of Ru/TiO2 following a 267 nm excitation is significantly blue-shifted, and the bathochromic shift with time is smaller. We show by global analysis of the spectrotemporal PL behavior that for both TiO2 and Ru/TiO2 the bathochromic shift with time is likely caused by the diffusion of electrons from the TiO2 bulk toward the surface. During this directional motion, electrons may recombine (non)radiatively with relatively immobile hole polarons, causing the PL spectrum to red-shift with time following excitation. The blue-shifted PL spectra and smaller bathochromic shift with time for Ru/TiO2 relative to TiO2 indicate surface PL quenching, likely due to charge transfer from the TiO2 surface into the Ru nanoclusters. When deposited on SiO2 and excited at 532 nm, Ru shows a strong emission. The PL of Ru when deposited on TiO2 is completely quenched, demonstrating interfacial charge separation following photoexcitation of the Ru nanoclusters with a close to unity quantum yield. The nature of the charge-transfer phenomena is discussed, and the obtained insights indicate that Ru nanoclusters should be deposited on semiconducting supports to enable highly effective photo(thermal)catalysis. To reference this document use: http://resolver.tudelft.nl/uuid:abf814c4-bdc9-4ca5-b8de-4ef3a6f3ec0c DOI https://doi.org/10.1021/acs.jpcc.3c04075 ISSN 1932-7447 Source The Journal of Physical Chemistry C, 127 (29), 14353-14362 Part of collection Institutional Repository Document type journal article Rights © 2023 Kasper Wenderich, Kaijian Zhu, Yibin Bu, F.D. Tichelaar, Guido Mul, Annemarie Huijser Files PDF acs.jpcc.3c04075.pdf 3.45 MB Close viewer /islandora/object/uuid:abf814c4-bdc9-4ca5-b8de-4ef3a6f3ec0c/datastream/OBJ/view