Electrochemical supercapacitor behavior of nanoparticulate rutile-type Ru1-xVxO2

ArticleJournal of Power Sources. 160(2):1480-1486 (2006)journal articl

Dip-coated La2Ti2O7 as a buffer layer for growth of Bi3.25La0.75Ti3O12 films with enhanced (0 1 1) orientation

Thin-films of La2Ti2O7 were obtained by dip-coating process using a precursor salt in nitric acid solution. The effects of solution concentration, withdrawal speed, post-annealing duration and temperature were investigated both on grain size and orientation of the La2Ti2O7 thin layers. In addition, a target with the required stoichiometry for PVD deposition of La-substituted Bi4Ti3O12 (BLT) was successfully sintered by spark plasma sintering (SPS) at 750 ◦C. Finally (0 1 1)-oriented BLT ferroelectric films have been grown by RF sputtering on (1 1 0)-oriented La2Ti2O7 polycrystalline thin-film. A preferential orientation of BLT thin films has been obtained after annealing at a temperature lower than 650 ◦C

Synthesis and physicochemical characterization of pigments based on molybdenum «ZnO-MoO3: Co2+»

International audienceMolybdatesZn1-xCoxMoO4(0≤ x ≤0.3) were elaborated by the Sol-Gel method with pH=3.The results obtained by DRX show a single-phase domain startingfrom 500°C for x ≤ 0.3 isostructural to ZnMoO4.The powder ofZn0.7Co0.3MoO4treated at 500°C and 700°C is formed by nano-sized primary crystallitesof size between 80 and 160nm. The colorimetric parameters (L a* b*) of powders obtained at 700°C present adegree of high bluing

Sol–gel synthesis and sintering of submicronic copper molybdate (α-CuMoO4) powders

A sol–gel method was proposed to prepare copper II molybdate α-CuMoO4 powders. A gel was first obtained via the polymerizable complex method, using citric acid as complexing and polymerizing agent, dried at 120 °C and decomposed at 300 °C. A calcination in the temperature range 400–500 °C for 2 h led to the pure phase α-CuMoO4. The different powders obtained were characterized by X ray diffraction analysis and by transmission (TEM) and scanning (SEM) electron microscopies. Ceramics were prepared using conventional sintering and spark plasma sintering (SPS) techniques. A maximal relative density of 94.8% was reached after conventional sintering at 520 °C for 2 h. In the case of SPS, the densification was optimized by varying the temperature, the time and the applied pressure. Higher densities, up to 98.7%, were obtained at very low temperature, i.e., 300 °C, for 5 min only under a pressure of 225 MPa

Luminescence in sulfides : a rich history and a bright future

Sulfide-based luminescent materials have attracted a lot of attention for a wide range of photo-, cathodo- and electroluminescent applications. Upon doping with Ce3+ and Eu2+, the luminescence can be varied over the entire visible region by appropriately choosing the composition of the sulfide host. Main application areas are flat panel displays based on thin film electroluminescence, field emission displays and ZnS-based powder electroluminescence for backlights. For these applications, special attention is given to BaAl2S4:Eu, ZnS:Mn and ZnS:Cu. Recently, sulfide materials have regained interest due to their ability (in contrast to oxide materials) to provide a broad band, Eu2+-based red emission for use as a color conversion material in white-light emitting diodes (LEDs). The potential application of rare-earth doped binary alkaline-earth sulfides, like CaS and SrS, thiogallates, thioaluminates and thiosilicates as conversion phosphors is discussed. Finally, this review concludes with the size-dependent luminescence in intrinsic colloidal quantum dots like PbS and CdS, and with the luminescence in doped nanoparticles

PEMBUATAN DAN KARAKTERISASI NANOKOMPOSIT MFe2O4 DAN MFe2O4-SiO2 (M = Cu, Ni)

 Nanocomposites of MFe2O4 and MFe2O4-SiO2 (M= Cu, Ni) were prepared by complexation and complexs polymerization methods using citric acid as complexing agent, tetraethylorthosilicate (TEOS), metal (Cu, Ni) nitrate and iron chloride as precursors. FT-IR spectroscopy was used to analysis the complexation and polymerization process. The decomposition of material was investigated by TG-DTA. Microstructure characterization was carried out by XRD and SEM. Peaks in XRD pattern indicate that the nanocomposites products consist of copper iron oxide (CuFe2O4) and (NiFe2O4) crystals, copper iron oxide crystal distributed in silica (CuFe2O4-SiO2) and nickel iron oxide crystal distributed in silica (NiFe2O4-SiO2). SEM images of CuFe2O4 and NiFe2O4 show that the composites have porous and spherical texture. The surface texture of CuFe2O4-SiO2 composite is triangel like and has porous but NiFe2O4-SiO2 is not regulated texture and has porous.  Keywords: MFe2O4, MFe2O4/SiO2, citric acid and complexs polymerization method  

Estudio de la incidencia del ion tipo A’ en la fase Ruddlesden-Popper (RP) de fórmula A’2la2Ti3O10 y su intercambio iónico sobre la actividad fotocatalítica para la producción de H2

La obtención de hidrógeno por medio de fuentes limpias y renovables usando la actividad fotocatalítica de las de capas perovskitas en la fase Ruddlesden-Popper (RP) de fórmula A’2La2Ti3O10, el objetivo de este proyecto, enfocó su estudio en el ion tipo A’ sintetizando tres compuestos usando K, Na y Li. Además, se realizó un intercambio iónico de los metales alcalinos en medio ácido para analizar los compuestos iniciales y los intercambiados en cuanto a su capacidad de intercambio, por medio de Absorción Atómica. Posteriormente se realizó la impregnación a las muestras intercambiadas con Oxido de Níquel (NiO). El propósito, evaluar la influencia de éste co-catalizador en la producción de hidrógeno, por fotocatálisis, usando como técnica de seguimiento cromatografía de gases. Se obtuvo como resultado que los fotocatalizadores con mayor porcentaje de degradación fueron los de Sodio y Potasio, impregnados con co-catalizador a una concentración de 0,1 %. Se confirmó, además, la actividad de los fotocatalizadores. Esta confirmación se llevó a cabo tras degradación de un colorante (azul de metileno) bajo radiación de lámpara de luz negra

Structural and microstructural characterization of CuMo(1-x)WxO4 (x ≤ 0.12) ceramics sintered by spark plasma sintering

Cupric molybdate CuMoO4is an interesting material due to their rich electrical, optical and magnetic properties. In this work, Solid solutions CuMo(1-x)WxO4(x≤0.12) were obtained by pyrolysis at 400 -700°C for 2 hours of a polymeric precursors elaborated by polymerizable complex method. For x ≤ 0.075, they were isostructural with α-CuMoO4 and for 0.075<x≤0.12, they were isostructural with γ-CuMoO4. Spark Plasma Sintering (SPS) at 300°C for 5 min under an applied pressure of 200 MPa led to variety CuMoO4-III for tungsten contents in the range 0.075-0.12

Synthesis and physicochemical characterization of pigments based on molybdenum «ZnO-MoO3: Co2+»

MolybdatesZn1-xCoxMoO4(0≤ x ≤0.3) were elaborated by the Sol-Gel method with pH=3.The results obtained by DRX show a single-phase domain startingfrom 500°C for x ≤ 0.3 isostructural to ZnMoO4.The powder ofZn0.7Co0.3MoO4treated at 500°C and 700°C is formed by nano-sized primary crystallitesof size between 80 and 160nm. The colorimetric parameters (L a* b*) of powders obtained at 700°C present adegree of high bluing