Hydrodesulfurization of model diesel using Pt/Al2O3 catalysts prepared by supercritical deposition

Haji, Shaker; Zhang, Ying; Kang, Dafei; Aindow, Mark; Erkey, Can

doi:10.1016/j.cattod.2004.10.011

Cited by 27 publications

(13 citation statements)

References 26 publications

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“…Controlling metal particle size and spatial distribution using a traditional catalyst preparation method (e.g., incipient wetness impregnation) can be problematic, resulting in low dispersion, spatial non-uniformity of the active metal, and unwanted modifications to the textural and chemical properties of the support. Recently, preparation of supported metal catalysts using supercritical carbon dioxide (SC-CO 2 ) as a solvent has received considerable attention [1][2][3][4][5]. Of this work, the preparation of palladium-silica aerogels using [Pd(hfac) 2 ] in SC-CO 2 is particularly relevant to the research presented herein [3].…”

Section: Introductionmentioning

confidence: 96%

Characterization of Pd/γ-Al2O3 Catalysts Prepared Using [Pd(hfac)2] in Liquid CO2

2008

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A series of Pd/c-Al 2 O 3 catalysts was prepared from [Pd(hfac) 2 ] (hfac = hexafluoroacetylacetonate) in liquid carbon dioxide using the method reported by Kim et al. [Chem Mater 18:4710 (2006)]. The catalysts were characterized using CO pulse chemisorption, diffuse-reflectance infrared Fourier transform spectroscopy (DRIFTS), X-ray absorption fine structure (XAFS) spectroscopy, X-ray photoelectron spectroscopy (XPS), and electron microscopy. The catalysts were reduced initially in the high-pressure CO 2 reaction cell using H 2 at 75°C. Samples were removed, stored in a desiccator, and re-reduced in situ at 250°C prior to pulse chemisorption, DRIFTS and XAFS. CO pulse chemisorption evidenced that the Pd dispersion decreased from 55% to 5% as the Pd loading increased from 0.58 to 3.94 wt.%. The asprepared 0.58 and 1.77 wt.% Pd/c-Al 2 O 3 catalysts (after air exposure) contained oxidized Pd species that were converted after in situ reduction to supported Pd particles. The average Pd particle sizes of these two catalysts (16 and 23 Å , respectively) estimated from the first-shell Pd-Pd coordination numbers are in good agreement with the CO chemisorption results. DRIFTS evidenced a prevalence of weakly bound linear CO (m CO = 2083 cm -1 ) adsorbed on the 0.58 wt.% Pd catalyst. A 2.95 wt% Pd catalyst (49 Å average particle size) also exhibited a strong linear CO band (m CO = 2093 cm -1 ).In contrast, CO chemisorption on a commercial 1 wt.% Pd/ Al 2 O 3 catalyst (37 Å average particle size) gave predominantly 2-fold bridging CO species. We infer that the supported Pd particles prepared from [Pd(hfac) 2 ] are rougher on the atomic scale (with a higher percentage of edge and corner atoms) than equivalently sized particles in conventionally prepared Pd/c-Al 2 O 3 catalysts.

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Section: Introductionmentioning

confidence: 96%

Characterization of Pd/γ-Al2O3 Catalysts Prepared Using [Pd(hfac)2] in Liquid CO2

2008

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“…28 The same result on the little inuence of higher temperature on HDS rate was observed by Haji et al when studying the HDS of model diesel on PT/Al 2 O 3 catalysts. 29 Additionally, higher temperatures promote thermal cracking, evidenced by the liquid products collected at 400 C and above that were dark brown; in contrast, the samples collected at lower temperatures were in light brown. This indicated that severe coking 30 due to the high temperature might have contributed to the decline of the sulfur removal efficiency.…”

Section: Hydrodesulfurizationmentioning

confidence: 99%

Recycling the CoMo/Al₂O₃ catalyst for effectively hydro-upgrading shale oil with high sulfur content and viscosity

et al. 2020

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“…Como ya se mencionó antes, en los catalizadores convencionales de HDT los promotores, Ni y Co, cambian la selectividad de la fase activa MoS 2 hacia la ruta DDS en la HDS de DBT (Mijoin et al, 2001). Aunque las razones de este comportamiento son aún objeto de debate (Topsøe, 2007y Grange y Vanhaeren, 1997, los resultados obtenidos en el presente trabajo indican que cuando el Pt actúa como promotor de la fase MoS 2 , en HDS, su efecto sobre la selectividad de la reacción del DBT es similar al del Ni y el Co. De la misma manera, la selectividad hacia la ruta de reacción del DBT de la fase Pt es preferencial hacia DDS (Haji et al, 2005). El hecho que la selectividad hacia la ruta HID aumente con el catalizador Pt(0,5)Mo(15), comparado con el de baja concentración de Mo, confirma que la fase MoS 2 es la que provee la mayoría de los sitios activos para la HID de la molécula de DBT (Mijoin et al, 2001).…”

Section: Hds De Dibenzotiofenounclassified

Comportamiento de Catalizadores PtMo/g-Al2O3-B2O3 en Reacciones de Hidrodesaromatización de Naftaleno e Hidrodesulfuración de Dibenzotiofeno

2009

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Resumen Con el propósito de estudiar la funcionalidades de catalizadores de hidrodesulfuración (HDS), se prepararon catalizadores PtMo/γ-Al 2 O 3-B 2 O 3 , con diferentes concentraciones de Mo y B, y se ensayaron en reacciones de hidrodesaromatización (HDA) de naftaleno en presencia de H 2 S, y HDS de dibenzotiofeno (DBT). Se observó que bajo las condiciones típicas del proceso de hidrotratamiento los catalizadores presentan un bajo desempeño en HDA y alta selectividad hacia la ruta de desulfurización directa en la reacción de HDS de DBT. El análisis del comportamiento catalítico del sistema PtMo en ambas reacciones es consistente con la hipótesis de la existencia de fases activas separadas de Pt y MoS 2 , donde el Pt cumple una doble función: como centro activo y como promotor de la fase MoS 2 .

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Hydrodesulfurization of model diesel using Pt/Al2O3 catalysts prepared by supercritical deposition

Cited by 27 publications

References 26 publications

Characterization of Pd/γ-Al2O3 Catalysts Prepared Using [Pd(hfac)2] in Liquid CO2

Characterization of Pd/γ-Al2O3 Catalysts Prepared Using [Pd(hfac)2] in Liquid CO2

Recycling the CoMo/Al₂O₃ catalyst for effectively hydro-upgrading shale oil with high sulfur content and viscosity

Comportamiento de Catalizadores PtMo/g-Al2O3-B2O3 en Reacciones de Hidrodesaromatización de Naftaleno e Hidrodesulfuración de Dibenzotiofeno

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Hydrodesulfurization of model diesel using Pt/Al2O3 catalysts prepared by supercritical deposition

Cited by 27 publications

References 26 publications

Characterization of Pd/γ-Al2O3 Catalysts Prepared Using [Pd(hfac)2] in Liquid CO2

Characterization of Pd/γ-Al2O3 Catalysts Prepared Using [Pd(hfac)2] in Liquid CO2

Recycling the CoMo/Al2O3 catalyst for effectively hydro-upgrading shale oil with high sulfur content and viscosity

Comportamiento de Catalizadores PtMo/g-Al2O3-B2O3 en Reacciones de Hidrodesaromatización de Naftaleno e Hidrodesulfuración de Dibenzotiofeno

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Recycling the CoMo/Al₂O₃ catalyst for effectively hydro-upgrading shale oil with high sulfur content and viscosity