Universidad Nacional Autónoma de México - CNyN

1st International Symposium on Nanoscience and Nanomaterials
Keywords: inhomogeneous thin film, optical spectroscopy.
Optical spectroscopy applied to thin film growth, is a noninvasive technique, which allows us, to
monitor emission lines and control the refractive index of the film. In this work we established the connection
between plasma spectra and resulting inhomogeneous thin film made by reactive sputtering. Our goal is to get
prescribed index profile of oxynitride inhomogeneous thin films, monitoring the emission spectra of the
plasma. We growth films with variation in refractive index, by controlling the flux rate between two gases,
oxygen and nitrogen in order to change the film stoichiometry. The plasma was monitored with a
spectrometer in the entire visible spectrum. By analyzing the spectral lines of Ar, N and O we observed their
temporal evolution during the growth of the layers. In-situ spectroscopic ellipsometry is used to characterize
the resulting coating, to obtain refractive index and thickness. We are able to grow films with 1.46 to 2.1
refractive index, depending the concentration of Si 3 N 4 or SiO 2 . The mixture is simulated with effective
medium approximation (EMA) model. We present results of inhomogeneous thin films with their
corresponding line spectra evolution, to emphasize the possibility of monitoring stoichiometry during the
deposition process. Partial support from the Conacyt-Mexico project 60351 and DGAPA-UNAM projects
IN100910 is acknowledged, Miss Abundiz thanks Conacyt for her scholarship.
O-018
MICROSTRUCTURAL STUDIES THROUGH HIGH RESOLUTION TRANSMISSION ELECTRON
MICROSCOPY AND X - RAY DIFFRACTOMETRY OF HDS CATALYTIC NANOMATERIALS
E. M. Rivera-Muñoz 1,a , R. Huirache-Acuña 2,b , R. Nava 3,c , C.V. Loricera 4,d , B. Pawelec 4,e
1 Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, A.P. 1-
1010 Querétaro, Qro. C.P. 76000, Mexico
2 Facultad de Ingeniería Química, Universidad Michoacana de San Nicolás de Hidalgo, Ciudad Universitaria,
Morelia, 58060, México.
3 Facultad de Ingeniería, Universidad Autónoma de Querétaro, Centro Universitario, Cerro de las campanas,
76000, Querétaro, Mexico
4 Instituto de Catálisis y Petroleoquímica, CSIC, c/ Marie Curie, 2, Cantoblanco, 28049 Madrid, Spain
a emrivera@fata.unam.mx, b rafael_huirache@yahoo.it, c rufino@uaq.mx, d cristinavalero@icp.csic.es,
e bgarcia@icp.csic.es
Keywords: HRTEM, HDS catalysts, SBA-15, SBA-16.
Mesoporous SBA-15 and SBA-16 materials were used as supports of novel ternary Co(Ni)-Mo-W
hydrodesulphurization (HDS) catalysts. These materials have shown a high catalytic activity in HDS of
dibenzothiophene (DBT) reactions, even much higher compared with commercial catalysts. An exploration
was made on structure of both the supports as well as on tri-metallic sulfide HDS catalysts prepared by
simultaneous impregnation via incipient wetness method. Prior to the catalytic test, the catalytic materials
were sulfided ex situ at atmospheric pressure in a tubular furnace heated up 673 K under a flow of H 2 S in
hydrogen (15%) and kept under those conditions for 4 h. The sulfided catalysts were tested in the HDS of
DBT performed in a batch reactor at 623 K and total pressure of 3.1 MPa. The calcined and fresh sulfide
catalysts were characterized by a variety of techniques, such as N 2 adsorption-desorption isotherms, TPD of
NH 3 , XRD and HRTEM. It has been found that both the morphology of the supports as its modification with
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