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In this study, a comparative analysis is made of TiO modified with Pt or Au in NO photoxidation under different radiation and humidity conditions. The metals were deposited on the TiO surface using two methods, photodeposition and chemical reduction. All catalysts were supported on borosilicate 3.3 plates using a dip-coating technique. These modified photocatalysts were characterized by X-ray diffraction analysis (XRD), UV–vis diffuse reflectance spectra (DRS), Brunauer-Emmett-Teller measurements (BET), transmission electron microscopy (TEM) and X-ray photoelectron spectrum analysis (XPS). It was found from the XPS results that Pt and oxidized Pt species coexist on the samples obtained by photodeposition and chemical reduction. In the case of Au, though other oxidation states were also detected the dominant oxidation state for both catalysts is Au. TEM results showed most Au-C particles are below 5 nm, whereas for Au-P the nanoparticles are slightly bigger. With UV irradiation, the Pt modified catalysts do not show any significant improvement in NO photocatalytic oxidation in comparison with the unmodified P25. For Au, both modified photocatalysts (Au-P and Au-C) exceed the photocatalytic efficiency of the unmodified P25, with Au-C giving slightly better results. The incorporation of metals on the TiO increases its activity in the visible region., We are grateful for the financial support of the Spanish Ministry of Economy and Competitiveness through the project IPT-2012-0927-420000 (HORMIFOT) and thank the Spanish Ministry of Science and Innovation for the UNLP10-3E-726 infrastructure co-financed with ERDF funds. Part of this work was supported by research funding from Project Ref. CTQ2015-64664-C2-2-P (MINECO/FEDER, EU). XPS and other research services of SITIUS University of Seville are also acknowledged. M.J. Hernández Rodríguez and E. Pulido Melián would also like to thank the University of Las Palmas de Gran Canaria for, respectively, their research training grant and postdoctoral contract.

A comparison is made in this study of the effectiveness of various commercial catalysts in the oxidation of NO by heterogeneous photocatalysis. The following catalysts were considered: Aeroxide TiO P25, Aeroxide TiO P90, Hombikat UV-100, Kronos vlp7000, CristalACTIV PC105, CristalACTIV PC500, Kemira 650 and Anatasa Aldrich. All catalysts were deposited by a dip-coating technique onto borosilicate 3.3 glass plates. Optimization of catalyst load showed no significant enhancement of photoactivity, in general, above a deposited mass of 1.16 mg cm. Differences between photocatalyst activity were more apparent at longer illumination times. Photoactivity decreased in the presence of humidity and differences in the adsorbed products were detected. Photocatalyst activity was strongly influenced by specific surface area, with the best results obtained by the catalysts with the largest surface area, namely the PC500, Hombikat and Kronos. Photocatalyst stability was demonstrated in successive reuse cycles., We are grateful for the financial support of the Spanish Ministry of Economy and Competitiveness through the project IPT-2012-0927-420000 (HORMIFOT) and CTQ2011-24784 and thank the Spanish Ministry of Science and Innovation for the UNLP10-3E-726 infrastructure, co-financed with ERDF funds. M.J. Hernández Rodríguez and E. Pulido Melián would also like to thank the University of Las Palmas de Gran Canaria for their research training grant and postdoctoral contract, respectively.

This work studied the degradation and adsorption of dimethylphthalate (DMP) using various TiO-based photocatalysts: TiO Aeroxide P25, Kronos vlp7000, Hombikat UV-100, Kemira 650 and a synthesized photocatalyst named SG750. As the photocatalysts with mixed anatase and rutile phases, P25 and SG750, showed greater activity than those of pure phase, an in-depth study was undertaken of these two catalysts in the adsorption and degradation of DMP. The degradation results were fitted with a high degree of correlation to the Langmuir-Hinshelwood model and those for adsorption to the Freundlich model. The Freundlich constants showed good correlation with FTIR observations of the DMP-P25 and DMP-SG750 interactions. These two photocatalysts were additionally modified by photodeposition with Pt and Au (0.5–1.5 wt%) to study the effect of these metals on degradation and mineralization kinetics., E. Pulido Melián would like to thank the University of Las Palmas de Gran Canaria for her postdoctoral contract.

TiO 2 nanoparticles have been prepared by amine template-assisted sol–gel precipitation and further hydrothermal treatment. We have investigated the effect of different amines (hydrazine and triethylamine) in the final surface and structural properties. It has been stated that the different amounts of amine could act as an interesting template upon hydrothermal treatment. Further thermal treatment also leads to a significant improvement in the photocatalytic properties of the studied systems. Surface and morphological features notably differ from TiO 2 prepared using different synthetic routes. Wide surface and structural characterization of the samples have been carried out, and correlations with precipitatio npH are pointed out from this characterization. In all cases, amine template TiO 2 obtained exhibit high conversion values for phenol photo-oxidation reaction. Further calcination treatment of all the studied systems clearly leads to photocatalytic conversions higher than that exhibited by TiO 2 Degussa P25.