Shape-controlled Synthesis of Silver and Palladium Nanocrystals using beta-Cyclodextrin

International @ MATERIAUX+GBEInternational audienceNon

Effect of cerium content and post-thermal treatment on doped anisotropic TiO2 nanomaterials and kinetic study of the photodegradation of formic acid

SSCI-VIDE+CARE:ECI2D+MME:HKO:GBE:CGUInternational audienceIn this work, the design of cerium doped TiO2 nanomaterials with tuned structural and textural properties is reported. The influence of the cerium content of doped TiO2 solids (x = 1 to 5 wt%) on the photocatalytic degradation of formic acid using UV-A light was evaluated.The best photocatalytic activity was reached for 1 wt% of cerium.The effect of post-thermal treatments was also herein highlighted by varying the calcination temperature between 400 degrees C and 700 degrees C for simultaneously doped- and cerium-free TiO2 samples. Characterization was performed by means of nitrogen adsorption-desorption isotherms at 77K, X-ray diffraction, Raman spectroscopy, Photoluminescence (PL) spectroscopy, and diffuse reflectance UV-vis spectroscopy. The presence of Ce limits the growth of TiO2 crystallite sizes during the post-thermal treatment and favors stabilization of the TiO2 anatase phase. The presence of cerium also increases the number of surface defects and transforms them to non-radiative centers able to capture the photogenerated electrons as observed by PL spectroscopy. This would leave photogenerated holes available improving consequentlythe photocatalytic activity for the oxidation of formic acid. Finally, a possible pathway mechanism is proposed to confirm the obtained results. (C) 2015 Published by Elsevier B.V

Impact of reduction degree of graphene oxide on the photocatalytic activity of graphene oxide/TiO2 nanotubes

SSCI-VIDE+CARE:ECI2D+GBE:CGU:MHMNational audienceNon

Impact of reduction degree of graphene oxide on the photocatalytic activity of graphene oxide/TiO2 nanotubes

SSCI-VIDE+CARE:ECI2D+GBE:CGU:MHMInternational audienceNon

Enhanced Photocatalytic Activity of Reduced Graphene Oxide / TiO2 Nanotubes Composites For Formic Acid Degradation

SSCI-VIDE+CARE:ECI2D+MHM:CGU:GBEInternational audienceReduced graphene oxide(RGO)/ TiO2 nanotubes composites were herein studied considering the effect of the GO reduction treatment and of its loading on textural, structural, electronic and optical properties of TiO2 nanotubes (NT). The resulting GO-NT composites were then evaluated for the photocatalytic degradation of formic acid in aquous solution and compared to their GO-free NT conterpart and to P25 used as references. Results emphasize a strong increase of the electron affinity and conductivity of the GO-NT composites particularly at low loading (1wt% GO) and if GO in only partially reduced (XPS). A remarkable gain in photocatalytic activity is then observed with a photocatalytic efficiency 3 and 1.9 times higher than for P25 and NT respectively

Design of TiO2 nanorods and nanotubes doped with lanthanum and comparative kinetic study in the photodegradation of formic acid

SSCI-VIDE+CARE:ECI2D+MME:GBE:CGU:HKOInternational audienceLanthanum doped 1D-TiO(2)nanomaterials (nanorods and nanotubes) with tuned structural and textural properties have been evaluated in the photocatalytic degradation of formic acid (FA) under UV conditions. La-doped nanorods and nanotubes calcined at 973 K show interesting photocatalytic properties with respect to La-free nanomaterials. The presence of La inhibits TiO2 crystallite growth and increases the lifetime of photo-generated electron-hole pairs. (C) 2014 Elsevier B.V. All rights reserved

Reduced graphene oxide/TiO2 nanotube composites for formic acid photodegradation

SSCI-VIDE+CARE:ECI2D+MHM:GBE:CGU:HKOInternational audienceThe influence on the photocatalytic performance of TiO2 nanotubes (NT) resulting from the addition of graphene oxide (GO) was studied. TiO2 nanotubes (NT) were prepared using alkaline hydrothermal treatment of TiO2 P25 followed by calcination at 400 C under air. GO-NT composites were then obtained by wet impregnation of the as-prepared TiO2 nanotubes onto graphene oxide before reduction under H2 at 200 C. In a first step, the influence of the reduction treatment was evaluated on GO alone to determine its role towards the nature of the oxygen-containing functional groups present. GO-NT composites were also characterized considering both the effect of the reduction treatment and of the GO weight loading on textural, structural, electronic, and optical properties of TiO2 nanotubes. The resulting GO-NT composites were finally evaluated for the photocatalytic degradation of formic acid and compared to TiO2 nanotubes alone and to P25. Results emphasize a strong increase of the electron affinity and conductivity of the GO-NT composites if graphene oxide is reduced at 200 degrees C. These enhanced properties lead to an easier separation of photogenerated charges and to a limitation of the recombination of electron-hole pairs. A dramatic gain in photocatalytic response is observed. Maximum in photocatalytic efficiency is reached at a GO loading of 1.0 wt% while further increase of GO weight loading blocks light penetration and depletes the photocatalytic response. (C) 2017 Elsevier B.V. All rights reserved