Facile synthesis of efficient visible active C-doped TiO2 nanomaterials with high surface area for the simultaneous removal of phenol and Cr(VI)

Nicolas Xanthopoulos
Pergamon-Elsevier Science Ltd, 2015
Article

Résumé

A single step synthesis of carbon doped TiO2 (anatase) nanomaterials have been reported by using combustion synthesis using ascorbic acid and citric acid fuels. X-ray diffraction studies indicated the formation of nanosized anatase titania, whereas, transmission electron microscopy confirmed the formation of nanosized TiO2 anatase. The carbon doping into TiO2 matrix was identified by X-ray photoelectron spectroscopy, whereas, thermogravirnetric study quantified the carbon doping. Diffuse reflettance UV-vis spectra indicated the band gap of less than 3 eV, a prerequisite for the photocatalytic activity under visible light irradiation. The N-2 adsorption studies revealed the high surface area (upto 290 m(2)/g) of the synthesized photocatalysts. Typical photocatalytic activity data indicated that the simultaneous removal of Cr(VI) and phenol is advantageous than degradation of the individual pollutants. (C) 2014 Elsevier Ltd. All rights reserved.

Official source

https://infoscience.epfl.ch/record/205377?ln=fr

À propos de ce résultat

Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.

Concepts associés

Chargement

Publications associées

Chargement

Nicolas Xanthopoulos
Pergamon-Elsevier Science Ltd, 2015
Article

Résumé

Official source

https://infoscience.epfl.ch/record/205377?ln=fr

À propos de ce résultat

Concepts associés (14)

vignette|upright=1.4|Machine XPS avec un analyseur de masse (A), des lentilles électromagnétiques (B), une chambre d'ultra-vide (C), une source de rayon X (D) et une pompe à vide (E) La spectrométrie

vignette|upright=1.5|Principe de fonctionnement du microscope électronique en transmission. vignette|Un microscope électronique en transmission (1976). La microscopie électronique en transmission (ME

redresse=.9|vignette|Bandes d'un semiconducteur. La bande interdite d'un matériau, ou gap, est l'intervalle, situé entre la bande de valence et la bande de conduction, dans lequel la densité d'états

Afficher plus

Concepts associés

Chargement

Publications associées (38)

Publications associées

Chargement

Effect of fuels on combustion synthesis of TiO2 - Towards efficient photocatalysts for methylene blue oxidation and Cr (VI) reduction under natural sunlight

Nicolas Xanthopoulos

A facile synthesis of carbon and nitrogen co-doped nano-TiO2 with pure anatase phase and high surface area was achieved by using combustion synthesis without the need of surfactants in a single step approach. Organic fuels such as hexamine, triethyl amine and glycine were tested as different fuels with titanylnitrate as the common oxidant. Effect of mixture of fuels has also been studied by taking the combinations of the above mentioned fuels. X-ray diffraction confirms the anatase phase titania and nano-crystalline size of the prepared catalysts was confirmed by transmission electron microscopy (TEM). N-2 adsorption confirmed the high surface area of nanocrystalline titania. Red shifts in UV-Vis absorption spectra was assigned due to the C and N-doping into the TiO2 matrix, whereas the presence of C and N in the TiO2 matrix was confirmed by X-ray photoelectron spectroscopy. Photocatalytic activity of the catalysts has been estimated from the oxidation of methylene blue (MB) and reduction of Cr (VI) under natural sunlight in open atmosphere. Among the TiO2 catalysts prepared, the one obtained with glycine as the fuel showed the best photocatalytic activity, which was correlated to the number of moles of gases evolved during the synthesis. (C) 2013 Elsevier B.V. All rights reserved.

Elsevier Science Sa2013

Chargement

Combustion synthesized TiO2 for enhanced photocatalytic activity under the direct sunlight-optimization of titanylnitrate synthesis

Vincent Laporte

Optimized synthesis of Ti-precursor 'titanylnitrate' for one step combustion synthesis of N- and C-doped TiO2 catalysts were reported and characterized by using powder X-ray diffraction (XRD), transmission electron microscopy (TEM), diffused reflectance UV-vis spectroscopy, N-2 adsorption and X-ray photoelectron spectroscopy (XPS). XRD confirmed the formation of TiO2 anatase and nano-crystallite size which was further confirmed by TEM. UV-DRS confirmed the decrease in the band gap to less than 3.0 eV, which was assigned due to the presence of C and N in the framework of TiO2 as confirmed by Xray photoelectron spectroscopy. Degradation of methylene blue in aqueous solution under the direct sunlight was carried out and typical results indicated the better performance of the synthesized catalysts than Degussa P-25. (C) 2012 Elsevier Ltd. All rights reserved.

Pergamon-Elsevier Science Ltd2012

Chargement

Effect of Crystallographic Phase (β vs. γ) and Surface Area on Gas Phase Nitroarene Hydrogenation Over Mo2N and Au/Mo2N

Fernando Cardenas Lizana, Lioubov Kiwi, Daniel André Samuel Lamey, Vincent Laporte

The catalytic action of Mo2N and Au/Mo2N has been assessed in the selective gas phase hydrogenation of p-chloronitrobenzene (p-CNB) to p-chloroaniline (p-CAN). The nitrides were synthesised via temperature programmed treatment of MoO3 in H-2 + N-2 and Au introduced by deposition-precipitation with urea. We have examined the influence of nitride crystallographic phase (tetragonal beta-Mo2N vs. cubic gamma-Mo2N) and surface area (7-66 m(2) g(-1)) on the catalytic response. Catalyst activation by temperature programmed reduction has been monitored and the reduced catalysts characterised in terms of BET area/pore volume, H-2 chemisorption/temperature programmed desorption (TPD), powder X-ray diffraction (XRD), elemental analysis, scanning (SEM) and transmission (TEM) electron microscopy and X-ray photoelectron spectroscopy (XPS) measurements. The formation of beta- and gamma-Mo2N was confirmed by XRD and TEM. gamma-Mo2N exhibits a platelet morphology whereas beta-Mo2N is characterised by an aggregation of small crystallites. Hydrogen chemisorption and TPD analysis have established a greater hydrogen uptake capacity (per unit area) for beta-Mo2N relative to gamma-Mo2N, which is associated with surface nitrogen deficiency, i.e. higher surface Mo/N for beta-Mo2N. Incorporation of Au on both nitrides resulted in an increase in surface hydrogen. The Au phase takes the form of nano-scale particles with a mean size of 7 and 4 nm on beta-Mo2N and gamma-Mo2N, respectively. Both beta-Mo2N and gamma-Mo2N promoted the exclusive hydrogenation of p-CNB to p-CAN where the beta-form delivered a higher specific (per m(2)) rate; the specific rate for gamma-Mo2N was independent of surface area. The inclusion of Au on both nitrides served to enhance p-CAN production.

Springer US2012

Chargement