Reactive Magnetron Sputter Deposition of Copper on TiO<inf>2</inf> Support for Photoreduction of CO<inf>2</inf> to CH<inf>4</inf>

© Published under licence by IOP Publishing Ltd. In this work, nanocrystalline Cu/TiO2 catalysts have been synthesized by using pulsed direct current (DC) reactive magnetron sputtering of Cu targets in an Ar atmosphere onto P25-TiO2 support. The oscillating bowl was used to make the uniform coating on the substrate. The Cu doping content was varied by adjusting the coating time. The thus-obtained catalysts were characterized by using the X-ray diffraction (XRD), UV-Vis spectroscopy, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). The photocatalytic activities of all catalysts were studied via the photocatalytic reduction of CO2 and H2O to CH4 under UV irradiation, and compared with the pure TiO2 support and conventional-impregnation-made Cu/TiO2. The results showed that the photocatalytic performance of sputtering-made Cu/TiO2 catalyst was much better than the pure TiO2 support. Therefore, reactive magnetron sputtering was a promising technique for deposition of metal onto the support and use as the catalytic process

Synthesis of Cu/TiO2 catalysts by reactive magnetron sputtering deposition and its application for photocatalytic reduction of CO2 and H2O to CH4

© 2019 In the present work, a series of Cu/TiO2 catalysts were successfully synthesized by using pulsed direct current (DC) reactive magnetron sputtering of Cu targets under Ar atmosphere onto various TiO2 supports. The physiochemical properties of the catalysts were characterized by using inductive coupled plasma spectroscopy (ICP), X-ray diffraction (XRD), UV–Vis spectroscopy, N2 physisorption, transmission electron microscopy (TEM), PL spectroscopy, and X-ray photoelectron spectroscopy (XPS). The photocatalytic activities of all the catalysts were studied via the photocatalytic reduction of CO2 and H2O to CH4 under UV light irradiation. The Cu/TiO2 catalysts exhibited higher photocatalytic activity than the uncoated TiO2 supports and the ones made using an impregnation technique. The electron trapping of copper species, which prolonged the electron-hole recombination process, promoted photocatalytic activity of the Cu-doped catalysts. Moreover, the specific morphologies of the Cu species deposited on TiO2 supports and the smaller change of bandgap energy of the sputter coated catalysts also resulted in an improvement of photocatalytic activity under UV light irradiation

Effect of reduction temperature on the characteristics and catalytic properties of TiO2 supported AuPd alloy particles prepared by one-step flame spray pyrolysis in the selective hydrogenation of 1-heptyne

SSCI-VIDE+ATARI+BPO:NSP:EEHInternational audienceThe bimetallic flame spray-synthesized AuPd/TiO2 catalysts (Au:Pd weight ratio 1:1) were reduced for 2 h under H-2 at two different temperatures (40 degrees C and 500 degrees C) and tested in the liquid phase selective hydrogenation of 1-heptyne under mild conditions (30 degrees C and 4 bar H-2). Based on TEM-EDX analysis of individual nanoparticles, reduction at 500 degrees C tends to homogenize the composition of the individual AuPd nanoparticles without significant changes of their average particle size and bulk composition. Higher reaction rate (245 mu mol s(-1) g cat.(-1)) was obtained on the AuPd/TiO2 R40 than on the AuPd/TiO2 R500 (223 mu mol s(-1) g cat.(-1)). Upon reduction at 500 degrees C, the bimetallic AuPd/TiO2 exhibited a similar degree of the strong-metal support interaction (SMSI) effect as the monometallic one. As revealed by XPS results, the ratios of Pd/Ti on both catalysts decreased by ca. 23%, due probably to the migration of TiOx species onto the metals. The highest yield of 1-heptene (similar to 93%) was obtained over the bimetallic AuPd/TiO2 reduced at 40 degrees C in 20 min reaction time under the reaction conditions used. The high temperature reduction is unnecessary for the improvement of catalyst performances when using supported bimetallic AuPd catalysts. (C) 2015 Elsevier B.V. All rights reserved

Variability of particle configurations achievable by 2-nozzle flame syntheses of the Au-Pd-TiO2 system and their catalytic behaviors in the selective hydrogenation of acetylene

SSCI-VIDE+ATARI+FCAInternational audienceFlame spray pyrolysi