In this work, we present an investigation concerning the evaluation of the catalytic
properties of Ni nanoparticles supported on ZrO2, SiO2, and MgAl2O4 for CO2 hydrogenation
to methane. The supports were prepared by coprecipitation and sol-gel, while Ni was incorporated
by impregnation (10–20 wt %). X-ray diffraction, nitrogen physisorption, temperature-programmed
reduction, H2 pulse chemisorption, Raman spectroscopy, X-ray photoelectron spectroscopy,
and transmission electron microscopy were the main characterization techniques employed.
A laboratory fixed-bed reactor operated at atmospheric pressure, a temperature range of 350–500 C,
and a stoichiometric H2/CO2 molar ratio was used for catalyst evaluation. The most outstanding
results were obtained with nickel catalysts supported on ZrO2 with CO2 conversions of close to
60%, and selectivity to methane formation was 100% on a dry basis, with high stability after 250 h of
reaction time. The majority presence of tetragonal zirconia, as well as the strong Ni–ZrO2 interaction,
were responsible for the high catalytic performance of the Ni/ZrO2 catalysts.
In this work, we present an investigation concerning the evaluation of the catalytic
properties of Ni nanoparticles supported on ZrO2, SiO2, and MgAl2O4 for CO2 hydrogenation
to methane. The supports were prepared by coprecipitation and sol-gel, while Ni was incorporated
by impregnation (10–20 wt %). X-ray diffraction, nitrogen physisorption, temperature-programmed
reduction, H2 pulse chemisorption, Raman spectroscopy, X-ray photoelectron spectroscopy,
and transmission electron microscopy were the main characterization techniques employed.
A laboratory fixed-bed reactor operated at atmospheric pressure, a temperature range of 350–500 °C,
and a stoichiometric H2/CO2 molar ratio was used for catalyst evaluation. The most outstanding
results were obtained with nickel catalysts supported on ZrO2 with CO2 conversions of close to
60%, and selectivity to methane formation was 100% on a dry basis, with high stability after 250 h of
reaction time. The majority presence of tetragonal zirconia, as well as the strong Ni–ZrO2 interaction,
were responsible for the high catalytic performance of the Ni/ZrO2 catalysts.
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El presente trabajo data sobre el análisis de factores que afectan el procedimiento de fabricación de una doble emulsión vía choque-térmico utilizando la metodología de diseño de experimentos (DoE). Los factores evaluados fueron temperatura, velocidad de agitación, tiempo de agitación, velocidad de adición, orden de adición y condición de adición. Los resultados indican que es posible obtener una doble emulsión en una sola etapa. La temperatura de la fase oleosa; a 100 °C y el tiempo de agitación; a 120 s. resultan ser clave para este proceso si se adiciona la parte caliente a la parte fría de forma rápida. La metodología DoE permite optimizar los parámetros de procedimiento de fabricación de una doble emulsión en una sola etapa.
El presente trabajo data sobre el análisis de factores que afectan el procedimiento de fabricación de una doble emulsión vía choque-térmico utilizando la metodología de diseño de experimentos (DoE). Los factores evaluados fueron temperatura, velocidad de agitación, tiempo de agitación, velocidad de adición, orden de adición y condición de adición. Los resultados indican que es posible obtener una doble emulsión en una sola etapa. La temperatura de la fase oleosa; a 100 °C y el tiempo de agitación; a 120 s. resultan ser clave para este proceso si se adiciona la parte caliente a la parte fría de forma rápida. La metodología DoE permite optimizar los parámetros de procedimiento de fabricación de una doble emulsión en una sola etapa.
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El desarrollo de nuevas tecnologías permite el diseño y automatización de equipos a bajo costo. Este trabajo propone el diseño, construcción y validación de un tensiómetro digital utilizando las nuevas tecnologías Arduino® e impresión 3D. La calibración del tensiómetro es llevada a cabo utilizando ocho soluciones estándares. Una superficie de PTFE® es utilizada para realizar su validación. Los resultados indican que este tensiómetro puede medir propiedades interfaciales, superficiales y energéticas de superficie de manera precisa. Para tensión superficial, el error encontrado es de ±1.70 mN/m. Este equipo puede ser utilizado para el desarrollo de diversos aditivos industriales tales como agentes humectantes, desmoldantes, plastificantes y promotores de adhesión.
El desarrollo de nuevas tecnologías permite el diseño y automatización de equipos a bajo costo. Este trabajo propone el diseño, construcción y validación de un tensiómetro digital utilizando las nuevas tecnologías Arduino® e impresión 3D. La calibración del tensiómetro es llevada a cabo utilizando ocho soluciones estándares. Una superficie de PTFE® es utilizada para realizar su validación. Los resultados indican que este tensiómetro puede medir propiedades interfaciales, superficiales y energéticas de superficie de manera precisa. Para tensión superficial, el error encontrado es de ±1.70 mN/m. Este equipo puede ser utilizado para el desarrollo de diversos aditivos industriales tales como agentes humectantes, desmoldantes, plastificantes y promotores de adhesión.
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Mesoporous TiO2, ZrO2 and ZrO2-TiO2 mixed oxides were synthesized by the sol-gel method and the
Au/TiO2, Au/ZrO2 and Au/ZrO2-TiO2 catalysts were prepared by deposition-precipitation method using
urea solution as a precipitating agent. These materials were characterized by UV–vis spectroscopy, X-ray
diffraction (XRD), N2 adsorption-desorption isotherms, transmission electron microscopy (TEM), X-ray
photoelectron spectroscopy (XPS), and in situ FTIR-pyridine (FTIR-Py) adsorption. XRD patterns of the
samples confirmed the formation of ZrTiO4 phase in the ZrO2-TiO2 mixed oxides. TEM micrographs
showed that nanosized gold particles on the catalyst had an average diameter smaller than 5 nm. Metallic
gold (Au0) and oxidized Au species (Au+
n ) on the surface of the catalysts were evidenced by UV–vis
and XPS characterization. In the partial oxidation of methanol (POM) reaction, among the six catalysts,
the high metallic Au0/Au+ ratio and low surface acidity in the Au/ZrO2 catalysts are chiefly responsible
for the highest hydrogen production rate in the whole temperature range between 210 and 300 ◦C.
Methanol decomposition as secondary reaction was favored on TiO2-based catalysts at higher temperature,
producing a large amount of CO. Formation of ZrO2-TiO2 solid solution resulted in generation of both
Brønsted and Lewis acid sites; as a result, dehydrogenation and oxidative dehydrogenation of methanol
was allowed over Au/ZrO2-TiO2 catalysts.
Mesoporous TiO2, ZrO2 and ZrO2-TiO2 mixed oxides were synthesized by the sol-gel method and the
Au/TiO2, Au/ZrO2 and Au/ZrO2-TiO2 catalysts were prepared by deposition-precipitation method using
urea solution as a precipitating agent. These materials were characterized by UV–vis spectroscopy, X-ray
diffraction (XRD), N2 adsorption-desorption isotherms, transmission electron microscopy (TEM), X-ray
photoelectron spectroscopy (XPS), and in situ FTIR-pyridine (FTIR-Py) adsorption. XRD patterns of the
samples confirmed the formation of ZrTiO4 phase in the ZrO2-TiO2 mixed oxides. TEM micrographs
showed that nanosized gold particles on the catalyst had an average diameter smaller than 5 nm. Metallic
gold (Au0) and oxidized Au species (Au+
n ) on the surface of the catalysts were evidenced by UV–vis
and XPS characterization. In the partial oxidation of methanol (POM) reaction, among the six catalysts,
the high metallic Au0/Au+ ratio and low surface acidity in the Au/ZrO2 catalysts are chiefly responsible
for the highest hydrogen production rate in the whole temperature range between 210 and 300 ◦C.
Methanol decomposition as secondary reaction was favored on TiO2-based catalysts at higher temperature,
producing a large amount of CO. Formation of ZrO2-TiO2 solid solution resulted in generation of both
Brønsted and Lewis acid sites; as a result, dehydrogenation and oxidative dehydrogenation of methanol
was allowed over Au/ZrO2-TiO2 catalysts.
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Catalytic decomposition of methane is an alternative route for steam reforming to produce hydrogen.
For this process, Ni-based and Co-based catalysts are well known for their activity. This paper presents
the synthesis and characterization of Ni/Ce–SiO2 and Co/Ce–TiO2 catalysts prepared by the
sol–gel method. Several techniques such as XRD, H2-TPR, SEM/EDS and HRTEM were employed for
catalysts characterization. The effect of a fixed amount of Ni or Co supported on mixed supports
(Ce–SiO2 or Ce–TiO2) on the CH4 decomposition reaction was tested. Based on the results, it is concluded
that, metal and supports, as well as the route of synthesis play an important role in the catalytic
activity for this reaction.
Catalytic decomposition of methane is an alternative route for steam reforming to produce hydrogen.
For this process, Ni-based and Co-based catalysts are well known for their activity. This paper presents
the synthesis and characterization of Ni/Ce–SiO2 and Co/Ce–TiO2 catalysts prepared by the
sol–gel method. Several techniques such as XRD, H2-TPR, SEM/EDS and HRTEM were employed for
catalysts characterization. The effect of a fixed amount of Ni or Co supported on mixed supports
(Ce–SiO2 or Ce–TiO2) on the CH4 decomposition reaction was tested. Based on the results, it is concluded
that, metal and supports, as well as the route of synthesis play an important role in the catalytic
activity for this reaction.
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