Combustion synthesis of cadmium sulphide nanomaterials for efficient visible light driven hydrogen production from water

Danièle Laub, Nicolas Xanthopoulos
Indian Acad Sciences, 2014
Article

Anion-doped cadmium sulphide nanomaterials have been synthesized by using combustion method at normal atmospheric conditions. Oxidant/fuel ratios have been optimized in order to obtain CdS with best characteristics. Formation of CdS and size of crystallite were identified by X-ray diffraction and confirmed by transmission electron microscopy. X-ray photoelectron spectroscopy confirmed the presence of C and N in the CdS matrix. The observed enhanced photocatalytic activity of the CdS nanomaterials for the hydrogen production from water (2120 mu mol/h) can be attributed to high crystallinity, low band gap and less exciton recombination due to the C and N doping.

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Danièle Laub, Nicolas Xanthopoulos
Indian Acad Sciences, 2014
Article

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https://infoscience.epfl.ch/record/202538?ln=fr

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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

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.

Pergamon-Elsevier Science Ltd2015

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Combinatorial High-Vacuum Chemical Vapor Deposition of Textured Hafnium-Doped Lithium Niobate Thin Films on Sapphire

Giacomo Benvenuti, Ali Dabirian, Scott Harada, Patrik Hoffmann, Yury Kuzminykh, Paul Muralt, Silviu Cosmin Sandu, Estelle Wagner

Combinatorial high-vacuum chemical vapor deposition (HV-CVD) was used to identify the conditions required to obtain hafnium-doped lithium niobate thin films on sapphire {001} substrates. Niobium tetraethoxydimethylaminoethoxide (Nb(OEt)(4)(dmae)), lithium tert-butoxide (Li(OBut)), and hafnium tert-butoxide (Hf(OBut)(4)) were used as precursors. X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicated that a single phase of textured {001} Hf-doped lithium niobate film was obtained under certain precursor flux conditions. The lithium content ([Li]/([Li] + [Nb])) of the textured film was estimated using Raman spectroscopy to be about 49 mol %. The presence of hafnium inside the films was confirmed by X-ray photoelectron spectroscopy (XPS) measurements, and the hafnium content of the textured film ([Hf]/([Hf] + [Nb])) was estimated to be about 3 mol %. XPS data confirmed that Hf and Nb, respectively, are in the +4 and +5 oxidation states inside the film. The film consists of nearly parallel {001} hafnium-doped lithium niobate columns with different in-plane orientations.

2011

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Performance and characterization of Ag-cotton and Ag/TiO2 loaded textiles during the abatement of E. coli

Juan Kiwi, Danièle Laub, César Pulgarin

The bacterial inactivation of Escherichia coli on Ag–cotton textiles were investigated under different experimental conditions with novel Ag-nanoparticles fixed on cotton textiles. The evaluation of the bactericide performance of the Ag–cotton was compared with the one observed for Ag–TiO2–cotton loaded textiles. The procedure used allowed us to prepare highly dispersed Ag-cluster species, 2–4 nm in size, as observed by transmission electron microscopy (TEM). By depth profile analysis, the X-ray photoelectron spectroscopy (XPS) revealed that the Ag profile in the 15 topmost layers remained almost constant before and after E. coli inactivation. The cotton loading was fairly low and of the order of 0.10 wt.% Ag/wt. of cotton. By infrared spectroscopy no modification of the Ag–cotton could be detected before or after E. coli inactivation due to the small absorption coefficient of Ag and the very low metal loading of Ag on the cotton. The E. coli was completely abated on Ag–cotton textiles immediately after the contact took place, due to the strong bacteriostatic effect of the dispersed silver clusters on the cotton surface.

2006

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