abstract
A new and original method, based on a non-aqueous sol-gel process, has been successfully established to produce quasi-spherical monodispersed TiO2 nanoparticles (NPs) and also noble metals (NM)@TiO2 heterostructures (NM=Au, Pt, Ag, 2 wt%), in one-pot and at low temperature. This has been achieved by using titanium oxyacetylacetonate as new single source precursors. This system has been deeply investigated by advanced characterization techniques. By using NMR, we have demonstrated the relatively complex mechanism behind this apparently simple synthesis, mediated by the reaction of the solvent and generated species, with many separate organic and organometallic molecules identified as being involved in the mechanism. The morphology and structure of the NM@TiO2 heterostructures were investigated by advanced scanning transmission electron microscopy while the chemical state of the noble metal nanoparticles was check by X-ray photoelectron spectroscopy (XPS). Undoped and noble metal (Au, Pt, Ag) decorated quasi/spherical TiO2 nanoparticles worked also as sensing interfaces, leading to the development of a highly sensitive conductometric NO gas sensor under both dark and UV-vis light irradiation, in the first result of its kind. Furthermore, the photocatalytic activity (PCA) was also evaluated, in the gas-solid phase, by monitoring the degradation of NOx under solar-light irradiation. Au-modified TiO2 showed improved photocatalytic efficiencies, compared to unmodified TiO2. Crown Copyright (C) 2017 Published by Elsevier B.V. All rights reserved.
keywords
GOLD NANOPARTICLES; TIO2 NANOCRYSTALS; TITANIUM-DIOXIDE; ROOM-TEMPERATURE; OPTICAL-PROPERTIES; LIGHT IRRADIATION; PARTICLE-SIZE; NANO-TITANIA; FERMI-LEVEL; THIN-FILMS
subject category
Chemistry; Engineering
authors
Karmaoui, M; Lajaunie, L; Tobaldi, DM; Leonardi, G; Benbayer, C; Arenal, R; Labrincha, JA; Neri, G
our authors
David Maria Tobaldi
Researcher
João António Labrincha Baptista
Full professoracknowledgements
M. Karmaoui thanks Fundacao para a Ciencia e a Tecnologia (FCT) for Grant No. SFRH/BPD/74477/2010. "This work was developed in the scope of the project CICECO-Aveiro Institute of Materials (Ref. FCT UID/CTM/50011/2013), financed by national funds through the FCT/MEC and when applicable co-financed by FEDER under the PT2020 Partnership Agreement". Authors acknowledge the PEstC/CTM/LA0011/2013 programme. The XPS, STEM and EDS studies were conducted at the Laboratorio de Microscopias Avanzadas, Instituto de Nanociencia de Aragon, Universidad de Zaragoza, Spain. R. Arenal gratefully acknowledges the, support from the Spanish Ministerio de Economia y Cornpetitividad (MAT2016-79776-P), from the Government of Aragon and the European Social Fund under the project "Construyendo Europa desde Aragon" 2014-2020 (grant number E/26). L. Lajaunie acknowledges Dr. Guillermo Antorrena (INA, Zaragoza) for the XPS measurements and fruitful discussions.