Supercritical preparation of hexagonal γ-alumina nanosheets and its electrocatalytic properties

Ma, Chuanli; Chang, Yong-Kui; Ye, Weichun; Shang, Wei; Wang, Chunming

doi:10.1016/j.jcis.2007.07.077

Cited by 46 publications

(24 citation statements)

References 51 publications

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“…Four types of deconvoluted XPS peaks were resolved, and their BE values were assigned to the three samples. The first peak in the O 1s spectra at 531.96 eV was assigned to atomic oxygen in the γ-Al 2 O 3 lattice [34,36]. The peak at 530.83 eV was assigned to the dissociatively adsorbed oxygen and implied a stronger bond between the adsorbed oxygen atoms and aluminium atoms [36].…”

Section: Resultsmentioning

confidence: 99%

“…The first peak in the O 1s spectra at 531.96 eV was assigned to atomic oxygen in the γ-Al 2 O 3 lattice [34,36]. The peak at 530.83 eV was assigned to the dissociatively adsorbed oxygen and implied a stronger bond between the adsorbed oxygen atoms and aluminium atoms [36]. The peak at 530.10 eV (for A and AFSG) was assigned to the hydroxyl oxygen (represented as O 2 -/hydroxyl in Table 2).…”

Section: Resultsmentioning

confidence: 99%

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Low Concentration Fe-Doped Alumina Catalysts Using Sol-Gel and Impregnation Methods: The Synthesis, Characterization and Catalytic Performance during the Combustion of Trichloroethylene

et al. 2014

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The role of iron in two modes of integration into alumina catalysts was studied at 0.39 wt% Fe and tested in trichloroethylene combustion. One modified alumina was synthesized using the sol-gel method with Fe added in situ during hydrolysis; another modification was performed using calcined alumina, prepared using the sol-gel method and impregnated with Fe. Several characterization techniques were used to study the level of Fe modification in the γ-Al2O3 phase formed and to correlate the catalytic properties during trichloroethylene (TCE) combustion. The introduction of Fe in situ during the sol-gel process influenced the crystallite size, and three iron species were generated, namely, magnetite, maghemite and hematite. The impregnated Fe-alumina formed hematite and maghemite, which were highly dispersed on the γ-Al2O3 surface. The X-ray photoelectron spectra (XPS), FT-IR and Mössbauer spectroscopy analyses revealed how Fe interacted with the γ-Al2O3 lattice in both catalysts. The impregnated Fe-catalyst showed the best catalytic performance compared to the catalyst that was Fe-doped in situ by the sol-gel method; both had better catalytic activity than pure alumina. This difference in activity was correlated with the accessibility of the reactants to the hematite iron species on the surface. The chlorine poisoning for all three catalysts was less than 1.8%.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Low Concentration Fe-Doped Alumina Catalysts Using Sol-Gel and Impregnation Methods: The Synthesis, Characterization and Catalytic Performance during the Combustion of Trichloroethylene

et al. 2014

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“…Para la relación 1.00, donde sólo hay Al presente, se observa una banda alrededor de los 900 cm −1 correspondiente a la deformación de los enlaces Al-OH, y una banda alrededor de los 1600 cm −1 que puede asignarse a las vibraciones de estiramiento y doblamiento de los enlaces con el grupo OH o agua ocluida dentro del sólido. Las bandas que se observan en el intervalo de los 300 a 1000 cm −1 se asignan a las vibraciones características de los enlaces Al-OH y O-Al-O-Al de la alúmina (Mac et al, 2008). En cuanto a las relaciones de Zn-Al entre 0.20 y 0. se observan marcadamente las bandas características de la hidrotalcita en la zona entre los 1000 y 400 cm −1 .…”

Section: Resultados Y Discusionesunclassified

ESTUDIO DE LA ESTABILIDAD ESTRUCTURAL DE ÓXIDOS MIXTOS Zn-Al TIPO HIDROTALCITA EN PRECURSORES CATALÍTICOS CoNiMo FRENTE HDS DE TIOFENO

Álvarez¹,

Linares²

2017

Rev. Fac. Cienc.

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. Artículo Investigación RESUMEN: La industria petrolera, es una de las principales fuentes responsable de emisiones atmosféricas tales como: CO, CO 2 , SO 2 , NO x , hidrocarburos y partículas suspendidas, la cual busca mitigar la contaminación ambiental originada en sus refinerías utilizando algunos procesos, como el hidrotratamiento (HDT). El corazón del HDT, son los catalizadores empleados, en función al soporte catalítico y los metales usados durante su formulación. Es por ello, que esta investigación se centró en estudiar la estabilidad estructural de óxidos mixtos Zn-Al tipo hidrotalcita (HT) en precursores catalíticos CoNiMo frente HDS de tiofeno, a una temperatura de calcinación de 450 • C. Inicialmente, se sintetizó el soporte catalítico HT a relaciones variables de Zn-Al de 0.00 a 1.00Al, una vez obtenido el intervalo óptimo de la HT (0.00-0.33Al), se procedió a formular los precursores catalíticos CoMo NiMo, a través de dos etapas de calcinación, la primera se impregna el soporte tipo hidrotalcita (HT) sin calcinar con los metales CoNi y CoMo, luego de impregnar con dichos metales se calcina por única vez; mientras que en la segunda etapa, se calcina los só-lidos antes de impregnar y después de la impregnación con los metales antes mencionados. Los resultados obtenidos denotan un excelente comportamiento para los catalizadores con doble etapa de calcinación, siendo los precursores CoMo más efectivos que NiMo; esto puede justificarse por las características fisicoquímicas de las fases de los metales involucrados y de sus vacantes de coordinación.

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“…The high frequency areas (680-1000 cm À1 ) are associated due to the stretching vibration band of AlO 4 tetrahedral [15]. In addition, the c-Al 2 O 3 exhibits a new absorption band at 1406 cm À1 which could be assigned as due to the longitudinal acoustical mode vibration of the nano-c-Al 2 O 3 [16]. Alumina possess well-defined hydroxyl bands whose nature and intensity are affected by alumina impurity content [17].…”

Section: Ft-irmentioning

confidence: 98%

Influence of Pt nanoparticles modified by La and Ce oxides on catalytic dehydrocyclization of n-alkanes

A.H.Samia

Mohammed

Faramawy

et al. 2015

Egyptian Journal of Petroleum

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Catalytic reforming accounts for a large share of the world's gasoline production, it is the most important source of aromatics for the petrochemical industry. In addition, reforming of hydrocarbon on the dual-function catalysts has been found to form fundamentally different products in hydrogen diluents. Typical catalysts employed for this reforming process are Pt/Al 2 O 3 and Pt-M/Al 2 O 3 , M being the promoter. These solids are characterized by both acid and metal functions which catalyze dehydrocyclization, dehydrogenation, isomerization and cracking processes. In this regard, information about cerium and lanthanum, as promoters, is hardly revealed. The present work aims to study the performance of Pt/Al 2 O 3 catalysts modified by lanthanum or cerium during the conversion of cyclohexane, n-hexane and n-heptane. Catalytic activities of the prepared catalysts were tested using a micro catalytic pulse technique. Physicochemical characterization of the solid catalysts such as, surface area (S BET ), Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), hydrogen-temperature programed reduction (H 2 -TPR), hydrogen-temperature-programed desorption (H 2 -TPD), CO 2 -TPD, NH 3 -TPD, high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) were depicted. Results indicated clearly that Pt/Al 2 O 3 catalyst is selective toward dehydrogenation to benzene which could be explained as due to the decrease in the active acid sites and the comparative segregation of the alumina support especially at 3% load of CeO. The presence of La 2 O 3 in the Pt/Al 2 O 3 catalyst promotes aromatization of n-hexane and n-heptane, also the dehydrocyclization of n-hexane is more difficult than that of n-heptane. Thus, modification of the Pt/Al 2 O 3 catalyst by La, resulted in a more active and selective reforming catalyst. ª 2015 The Authors. Production and hosting by Elsevier B.V. on behalf of Egyptian Petroleum Research Institute. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

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Supercritical preparation of hexagonal γ-alumina nanosheets and its electrocatalytic properties

Cited by 46 publications

References 51 publications

Low Concentration Fe-Doped Alumina Catalysts Using Sol-Gel and Impregnation Methods: The Synthesis, Characterization and Catalytic Performance during the Combustion of Trichloroethylene

Low Concentration Fe-Doped Alumina Catalysts Using Sol-Gel and Impregnation Methods: The Synthesis, Characterization and Catalytic Performance during the Combustion of Trichloroethylene

ESTUDIO DE LA ESTABILIDAD ESTRUCTURAL DE ÓXIDOS MIXTOS Zn-Al TIPO HIDROTALCITA EN PRECURSORES CATALÍTICOS CoNiMo FRENTE HDS DE TIOFENO

Influence of Pt nanoparticles modified by La and Ce oxides on catalytic dehydrocyclization of n-alkanes

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