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Synthesis of carbon nano-onions doped with nitrogen using spray pyrolisis

EDUARDO TOVAR MARTINEZ JOSE ADAN MORENO TORRES JORGE VALENTIN CABRERA SALAZAR MARISOL REYES REYES Luis Felipe Cházaro Ruiz ROMAN LOPEZ SANDOVAL (2018)

"In this work, we have synthesized carbon nano-onions (CNOs) doped with nitrogen and iron carbide core. These nanostructures were synthesized pyrolysing various alcohol-benzylamine reaction mixtures. These CNOs showed a certain degree of functionalization of their surfaces, depending of the solvent, as well as n-type doping due to the inclusion of N atoms in the graphene layers. Ratios of O atoms to C atoms as well as to N atoms of the pyrolyzed solution play an important role in the morphology of the CNOs and on the phase of the iron core. Differences in the morphology of the samples have an important effect on their electrical conductivity as well as in their electrochemical properties. Synthesized samples showing well-defined CNOs, the sintering between them is negligible, have a low conductivity and higher capacitance, while those samples showing the best conductivities and lower capacitances, the CNOs in samples are connected between them by turbostratic graphite ribbons, in similar way to the CNOs synthesized from carbon nanodiamond annealed in argon atmosphere."

Article

Electrochemical performance Raman-spectroscopy Oxygen Nanotubes Reduction Nanodiamond Nanoparticles Graphene Soot Microscopy BIOLOGÍA Y QUÍMICA QUÍMICA QUÍMICA

Structural Analysis of Carbon Nanotubes of Various Diameters Grown by Spray Pyrolysis using Raman Spectroscopy

ELSA GABRIELA ORDOÑEZ CASANOVA MANUEL ROMAN AGUIRRE ALFREDO AGUILAR ELGUEZABAL FRANCISCO ESPINOSA MAGAÑA (2015)

Carbon nanotubes of various diameters and length were grown through the alternative spray pyrolysis method [1-2], using propanol, buthanol and cyclohexanol as the carbon source, at temperatures higher than 700°C. In this investigation,we present a comparative analysis of the structures and morphology of the three samples by Raman spectroscopy in order to verify whether it is possible, by using this method, to obtain carbon nanotubes of small diameters at a low cost. The Raman spectra were acquired by the LabRam Horiba HR system using a He- Ne laser at 632.8 nm and 14.2 mW, equipped with a CCD detector column at 75 ° C. The resolution obtained was of approximately 1 cm -1

Conference proceedings

Raman spectroscopy BIOLOGÍA Y QUÍMICA QUÍMICA QUÍMICA FÍSICA OTRAS

Synthesis of crystalline silica-carbonate biomorphs of Ba(II) under the presence of RNA and positively and negatively charged ITO electrodes: obtainment of graphite via bioreduction of CO2 and Its Implications to the chemical origin of life on primitive earth

Abel MORENO Mayra Cuéllar_Cruz (2020)

Since Earth was formed, in the Precambrian era up until our present days, electric current has participated in the morphology and chemical composition of organic and inorganic structures. Attempting to elucidate the mechanism by which electric current participated in the creation of the first cell in the Precambrian era is an intriguing and of a permanent subject of interest to be studied. One way of emulating the formation of structures similar to those that might have existed in the Precambrian era in the presence of a biomolecule and an electric current source is to use as a model, the silica-carbonate of alkaline earth metal compounds known as biomorphs. The objective of this work was to assess the influence exerted by an electric current (negatively or positively charged indium tin oxide electrodes) on the formation of biomorphs in the presence of RNA. The compounds obtained under both electric charges were visualized through scanning electron microscopy (SEM), and their chemical composition was analyzed through Raman spectroscopy. The biomorphs obtained under a positive electric current correspond to aragonite-type BaCO3(I) and calcite-type BaCO3(II). Whereas, under a negative current, carbon graphite and aragonite-type BaCO3(I) were obtained. To the best of our knowledge, this is the first evidence showing that the presence of RNA and the electric current is fundamental in the rearrangement of atoms, suggesting that organic and inorganic compounds have coexisted since the primitive era.

Article

https://doi.org/10.1021/acsomega.0c00068

BIOLOGÍA Y QUÍMICA Raman-Spectroscopy Glassy-carbon Reduction Complex Dioxide

Characterization of nanostructured SnO2 films deposited by reactive DC-magnetron sputtering

MIGUEL ANGEL CAMACHO LOPEZ JOSE ROMAN GALEANA CAMACHO ALEJANDRO ESPARZA GARCIA CELIA ANGELINA SANCHEZ PEREZ Christian Julien (2013)

Nanostructured tin oxide thin films were deposited on silicon and glass slides substrates by reactive DC-Magnetron sputtering using a tin target in a mixture of argon and oxygen gases. The substrate temperature was varied in the range from 53 to 243 oC, keeping the other deposition parameters constant. The tin oxide films were characterized by: Scanning Electron Microscopy, Energy Dispersive Spectrometry, X Ray Diffraction, microRaman spectroscopy and UV-VIS spectroscopy. It was found that the substrate temperature has an effect mainly on the structural, morphological and optical properties of the thin films. At 53 and 90 oC the tetragonal crystalline phase was obtained while a mixture of crystalline phases (o-SnO2 and t-SnO2) was obtained at 148, 185 and 243 oC.

Article

Física, Astronomía y Matemáticas DC-magnetron sputtering tin oxide raman spectroscopy CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA

Characterization of silicon rich oxides with tunable optical band gap on sapphire substrates by photoluminescence, UV/Vis and raman spectroscopy

JOSE ALBERTO LUNA LOPEZ MARIANO ACEVES MIJARES (2008)

A detailed analysis of the optical properties of silicon rich oxides (SRO) thin films and the factors that influence them is presented. SRO films with different Si content were synthesized via LPCVD (low pressure chemical vapor deposition) on sapphire substrates. Photoluminescence (PL), UV/Vis and Raman spectroscopy were used to characterize the samples. An intense emission in blue region was found. An interesting fact is that the optical band gap correlates linearly with the reactants ratio, which allows the tuning of the band gap. The influence of parameters such as substrate, Si content, annealing temperature and annealing time on the optical properties are discussed and the possible mechanisms of the photoluminescence are compared with our experimental data.

Se presenta un análisis detallado de las propiedades ópticas de películas delgadas de oxido de silicio rico en silicio (SRO) y los factores que tienen influencia en las propiedades físicas. Películas de SRO con diferente contenido de silicio fueron depositadas por LPCVD (Deposito químico en fase vapor a baja presiónlow pressure chemical vapor deposition) sobre substratos de zafiro. Fotoluminiscencia (FL) espectroscopia UV/Vis y Raman se usaron para caracterizar las muestras. Se encontró una intensa emisión en la región azul. La característica más interesante es la banda prohibida óptica, que se correlaciona linealmente con la razón de los reactivos, lo cual permite el ajuste de la banda prohibida. Las influencias de los parámetros como el substrato, contenido de silicio, temperatura y tiempo de recocido en las propiedades ópticas se discuten y los posibles mecanismos de fotoluminiscencia son comparados con los datos experimentales.

Article

Silicon rich oxides Optical properties Photoluminiscence Silicon nano crystals Nanostructured materials Luminescence Raman spectroscopy Silicon rich oxides Óxidos de silicio Propiedades ópticas Fotoluminiscencia CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ELECTRÓNICA

Characterization of a C-based coating applied on an AA6063 alloy and developed by a novel electrochemical synthesis route

Adriana Gallegos-Melgar YAEL GONZALEZ LOPEZ Arturo Abúndez-Pliego Francisco Javier Flores Ruiz J.C. Díaz-Guillén Jose Antonio Betancourt Cantera Maricruz Hernandez-Hernandez Luis Gerardo Trápaga Martínez Carlos Agustín Poblano Salas Jorge Leobardo Acevedo Dávila Jan Mayén Chaires (2020)

This research aimed to obtain a C-based coating electrochemically applied on an AA6063 alloy. Two electrochemical cells were designed and manufactured to obtain the C-based coating film on flat and cylindrical samples. Structural and microstructural characterizations were performed along with fatigue and corrosion performance testing. The structural and microstructural characterization revealed that the C-based coating deposited on AA6063 corresponded to carbon nanofibers and/or polycrystalline graphite. The performance testing showed an increase in fatigue life along with a decrease in corrosion resistance. The fracture surfaces of the fatigued samples were inspected by Scanning Electron Microscopy and 3D optical microscopy to correlate them with fatigue life estimation. The aforementioned process is a step towards the future development of a complete coating system that will overcome corrosion susceptibility. The carbon film obtained by this electrochemical route has not previously been reported elsewhere.

Author contributions: Conceptualization, A.G.-M., Y.G.-L., A.A. and J.M.; Data curation, Y.G.-L., F.J.F.-R., J.C.D.-G., J.A.B.-C., M.H.-H. and J.M.; Formal analysis, A.G.-M. and J.M.; Funding acquisition, A.A., G.T.-M. and C.A.P.-S.; Investigation, A.G.-M., Y.G.-L., F.J.F.-R., J.C.D.-G., J.A.B.-C., M.H.-H. and J.M.; Methodology, A.G.-M., A.A. and F.J.F.-R.; Project administration, J.M.; Resources, J.L.A.-D.; Supervision, A.G.-M. and J.L.A.-D.; Writing—original draft, A.G.-M.; Writing—review & editing, G.T.-M., C.A.P.-S. and J.M. All authors have read and agreed to the published version of the manuscript.

Funding: The funding for this research was provided by CONACYT through the project grant INFR-293468 and FOINS 2016-01-2488.

Acknowledgments: We thank Cátedras CONACYT and CONACYT National System of Researchers for supporting the researchers with ID numbers 2309 and 5150. we suggest to move the funding information to the Funding section.

Conflicts of interest: The authors declare no conflict of interest.

Article

C-based coating Raman spectroscopy AFM characterization Fatigue Corrosion INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS INGENIERÍA Y TECNOLOGÍA QUÍMICAS TECNOLOGÍA DE LA CORROSIÓN TECNOLOGÍA DE LA CORROSIÓN

Clasificación de piel utilizando técnicas ópticas

JOSE FABIAN VILLA MANRIQUEZ (2013)

Uno de los principales problemas encontrados al realizar mediciones de espectros

Raman en la piel es el de conocer la cantidad de potencia que se debe hacer incidir

sobre ésta para obtener la mejor señal Raman. Esto es importante cuando se utiliza

un láser como fuente de excitación pues se debe tener precaución para no inducir quemaduras.

Por ello, la importancia de un clasificador de piel mediante humectación,

el cual ayudaría a seleccionar la potencia adecuada para medir el espectro. En este

trabajo se hizo un estudio de la espectroscopia Raman en tejido biológico in vivo

para encontrar las principales bandas del colágeno, con el fin de clasificar la piel

mediante humectación y determinar mediante espectroscopia Raman si la piel se encuentra

humectada o no-humectada; ya que la humectación es un factor importante

el cual influye en la intensidad del espectro Raman. Para dicha clasificación se utilizó

la técnica de la función discriminante lineal de Fisher analizando las principales

bandas del colágeno en los espectros Raman para obtener los coeficientes de dicha

función y con la ayuda de un analizador de humectación comercial (skin moisture

analyzer SK-III) se corroboraron los resultados obtenidos con una sensitividad de

91.66% en la mejor zona de medición la cual fue el dedo índice, por lo que concluimos

que la espectroscopia Raman es un técnica factible para la clasificación de

la piel mediante humectación.

Master thesis

Raman spectroscopy Biological tissues Skin Pincipal component analysis PCA CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ÓPTICA

High-pressure characterization of multifunctional CrVO4

Pablo Botella Vives SINHUE LOPEZ MORENO Daniel Errandonea Francisco Javier Manjon Juan Angel Sans Tresserras David Vie Alberto Vomiero (2020)

"The structural stability and physical properties of CrVO(4)under compression were studied by x-ray diffraction, Raman spectroscopy, optical absorption, resistivity measurements, andab initiocalculations up to 10 GPa. High-pressure x-ray diffraction and Raman measurements show that CrVO(4)undergoes a phase transition from the ambient pressure orthorhombic CrVO4-type structure (Cmcm space group, phase III) to the high-pressure monoclinic CrVO4-V phase, which is proposed to be isomorphic to the wolframite structure. Such a phase transition (CrVO4-type -> wolframite), driven by pressure, also was previously observed in indium vanadate. The crystal structure of both phases and the pressure dependence in unit-cell parameters, Raman-active modes, resistivity, and electronic band gap, are reported. Vanadium atoms are sixth-fold coordinated in the wolframite phase, which is related to the collapse in the volume at the phase transition. Besides, we also observed drastic changes in the phonon spectrum, a drop of the band-gap, and a sharp decrease of resistivity. All the observed phenomena are explained with the help of first-principles calculations."

Article

CrVO4-type High-pressure Phase transition X-ray diffraction Raman spectroscopy Optical absorption CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA FÍSICA

Raman Spectroscopy and Microstructural Study of Natural Graphite Processed by High-Energy Ball Mill

JOSE MANUEL MENDOZA DUARTE Ricardo Martínez Sánchez IVANOVICH ESTRADA GUEL (2013)

Las aleaciones de aceros inoxidables súper dúplex (AISD) son utilizadas en la industria

petrolera y química, en plataformas marinas, así como en medios donde se requiera una alta

resistencia a la corrosión. Debido a ello resulta importante evaluar su comportamiento en

diferentes medios, mediante el ensayo CERT (ensayo a velocidad de extensión constante) para

la determinación de la susceptibilidad al agrietamiento por corrosión asistida por esfuerzo (CAE),

del mismo modo se utiliza la técnica de Curvas de polarización cíclicas para correlacionarla con

el ensayo CERT y corroborar si el material es susceptible o no al medio, los resultados

muestran que el acero inoxidable súper-dúplex no es susceptible a corrosión bajo tensión en los

medios ensayados

Conference proceedings

Raman Spectroscopy BIOLOGÍA Y QUÍMICA QUÍMICA QUÍMICA FÍSICA OTRAS

Oxygenated surface of carbon nanotube sponges: electroactivity and magnetic studies

ALEJANDRO JAVIER CORTES LOPEZ Emilio Muñoz Sandoval FLORENTINO LOPEZ URIAS (2019)

"We report the synthesis of nitrogen-doped carbon nanotube sponges (N-CNSs) by pyrolysis of solutions of benzylamine, ferrocene, thiophene, and isopropanol-based mixture at 1020 degrees C for 4 h using an aerosol-assisted chemical vapor deposition system. The precursors were transported through a quartz tube using a dynamic flow of H-2/Ar. We characterized the N-CNSs by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, and thermogravimetric analysis. We found that isopropanol, isopropanol-ethanol, and isopropanol-acetone as precursors promote the formation of complex-entangled carbon fibers making knots and junctions. The N-CNSs displayed an outstanding oxygen concentration reaching a value of 9.2% for those synthesized with only isopropanol. We identified oxygen and nitrogen functional groups; in particular, the carbon fibers produced using only isopropanol exhibited a high concentration of ether groups (C-O bonds). This fact suggests the presence of phenols, carboxyl, methoxy, ethoxy, epoxy, and more complex functional groups. Usually, the functionalization of graphitic materials is carried out through aggressive acid treatments; here, we offer an alternative route to produce a superoxygenated surface. The understanding of the chemical surface of these novel materials represents a huge challenge and offers an opportunity to study complex oxygen functional groups different from the conventional quinone, carboxyl, phenols, carbonyl, methoxy, ethoxy, among others. The cyclic voltammetry measurements confirmed the importance of oxygen in N-CNSs, showing that with high oxygen concentration, the highest anodic and cathodic currents are displayed. N-CNSs displayed ferromagnetic behavior with an outstanding saturation magnetization. We envisage that our sponges are promising for anodes in lithium-ion batteries and magnetic sensor devices."

Article

Chemical-vapor-deposition Thermal-decomposition Raman-spectroscopy Highly efficient Porus carbon Growth Nanostructures Networks Ethylene Sorption BIOLOGÍA Y QUÍMICA QUÍMICA QUÍMICA