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Lima-Gutierrez J.,Autonomous University of Puebla | Lima-Gutierrez J.,Ibero-American University of Mexico | Palomino-Merino R.,Autonomous University of Puebla | Arroyo Carrasco M.L.,Autonomous University of Puebla | And 3 more authors.
Journal of Nanomaterials | Year: 2013

A novel nanohybrid material based on MMA-Silica has been synthesized with an organic dye dopant (R6G) to tailor the optical properties. This novel material can be used on several devices such as active laser media for an organic solid state laser, OLEDs, or as a characterization media for new organic dye molecules. Thin films were deposited by dip-coating and characterized by absorption and reflection UV-VIS, photoluminescence, SEM, and Z-scan technique to verify their nonlinear behavior. R6G dye dopant has been used to verify that the nanohybrid matrix does not inhibit its optical properties. © 2013 J. Lima-Gutiérrez et al. Source


Gonzalez-Rivera Y.A.,Autonomous University of Puebla | Meza-Rocha A.N.,Autonomous University of Puebla | Aquino-Meneses L.,CINVESTAV | Jimenez-Sandoval S.,CINVESTAV | And 6 more authors.
Ceramics International | Year: 2016

Nd3+ doped ZnV2O6 and Zn2V2O7 samples were synthetized by using melt-quenching method. X-ray diffraction patterns indicate that both samples are polycrystalline. The crystallinity was also verified by Raman scattering, from which the different vibrational modes of ZnV2O6 and Zn2V2O7 were detected. Electron dispersive spectroscopy (EDS) analysis shows that the Nd3+ incorporation into the ZnV2O6 and Zn2V2O7 hosts is around 0.9±0.1 and 0.2±0.1 at%, respectively. The micrographs obtained by Scanning Electron Microscopy, reveal that the Nd3+ doped ZnV2O6 sample is predominantly composed by micro-rods, whereas the Nd3+ doped Zn2V2O7 one is only composed by irregular blocks. The band gap energies (Eg) were calculated from the diffuse reflectance spectra by the Kubelka-Munk equation; Eg values resulted to be 2.24 and 2.86eV for the Nd3+ doped ZnV2O6 and Zn2V2O7 samples, respectively. By means of two points dark conductivity measurements, conductivity values in the 10-4-10-6 and 10-6-10-8(Ωcm)-1range for the Nd3+ doped ZnV2O6 and Zn2V2O7 samples were measured, respectively. The conductivity as a function of the temperature indicated a semiconductor behavior. The photoluminescence spectra upon Ar+ laser excitation at 488nm, exhibited the Nd3+ characteristics emissions. For instance, the Nd3+ doped ZnV2O6 sample displayed the Nd3+ 4F5/2→4I9/2 and 4F3/2→4I9/2 emissions; while the Nd3+ doped Zn2V2O7 one showed the Nd3+ characteristic emissions associated with the 4G7/2, 4F9/2, 4F5/2 and 4F3/2→4I9/2 transitions. The lifetimes were 80 and 130μs for the Nd3+ doped ZnV2O6 and Zn2V2O7 samples, respectively. All these results suggest a successful synthesis of Nd3+ doped zinc vanadate compounds by the melt-quenching technique. © 2016. Source


Sanchez-Marquez J.A.,University of Guanajuato | Fuentes-Ramirez R.,University of Guanajuato | Cano-Rodriguez I.,University of Guanajuato | Gamino-Arroyo Z.,University of Guanajuato | And 3 more authors.
International Journal of Polymer Science | Year: 2015

Membranes made of carbon nanotubes and cellulose acetate with polyacrylic acid were designed in order to study their properties and their applicability for chromium removal. The membranes were prepared by phase inversion method using cellulose acetate and polyacrylic acid. Carbon nanotubes were added to the membrane during their process of synthesis in proportions of 1% by weight. The pores in the material are formed in layers, giving the effect of depth and forming a network. Both the carbon nanotubes and membranes were characterized by IR, Raman, and SEM spectroscopy. In addition, the concentration of acidic and basic sites and the surface charge in the materials were determined. The concentration of acid sites for oxidized nanotubes was 4.0 meq/g. The removal of Cr(VI) was studied as a function of contact time and of initial concentration of Cr(VI). The removal of Cr(VI) (90%) mainly occurs in a contact time from 32 to 64 h when the initial concentration of Cr(VI) is 1 mg/L. © 2015 J. A. Sánchez-Márquez et al. Source


Hernandez M.A.,Autonomous University of Puebla | Rojas F.,Metropolitan Autonomous University | Portillo R.,Autonomous University of Puebla | Salgado M.A.,Autonomous University of Puebla | And 2 more authors.
International Journal of Nanotechnology | Year: 2016

This paper deals with the emergence of pores in natural erionite zeolite during ion-exchange treatment with aqueous Na+, Mg2+ and Ca2+ solutions of different concentrations. The exchange took place at variable time and temperature of exposure. The effect of this cationic exchange upon the zeolite micropores is analysed by scanning electron microscopy, energy dispersive X-ray spectroscopy and N2 adsorption at 76 K. The characterisation results suggest the presence of Na+ at the pores' mouth that causes an increased adsorption inside nanocavities as well as on the external area of the exchanged zeolites. The generation of pores emerging in erionite zeolites after ion exchange was evaluated through Dubinin-Astakhov and classical Barrett- Joyner-Halenda methods. Depending on the exchanging conditions, Na+ was found to be well distributed and accessible for N2 adsorption. The results indicate that the tested exchange treatments with Na+ favour creation of emerging pores, as an increase of the adsorption capacity occurs. © 2016 Inderscience Enterprises Ltd. Source


Gonzalez-Rivera Y.A.,Autonomous University of Puebla | Cervantes-Juarez E.,Autonomous University of Puebla | Aquino-Meneses L.,Autonomous University of Puebla | Lozada-Morales R.,Autonomous University of Puebla | And 9 more authors.
Journal of Luminescence | Year: 2014

A group of samples from the CdO-V2O5 binary system, particularly with high V2O5 content, doped with Er 3+ were prepared. The set of samples was fabricated using the conventional melt-quenching method. Depending on the proportion of the used reactants, the existence of V2O5 and of CdV 2O6 was identified from X-ray diffraction measurements and Raman spectroscopy. Depending on the relative concentrations of CdO and V 2O5, different types of morphologies for each sample were found in a scanning electron microscope. Their chemical composition was measured from energy dispersive spectroscopy in the same instrument. An effective Er-doping of the order of 1.0±0.35 at% was found for each sample. From optical absorption data, the composition dependent optical band gap was determined with values between 1.94 and 2.29 eV. Finally, photoluminescence experiments showed, in the samples with the highest V2O5 content, wide bands associated to oxygen vacancies. For the rest of the samples emissions from electronic transitions of Er3+ ions were detected. © 2014 Elsevier B.V. Source

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