Structural features and performance of LaNi1−xRhxO3 system for the dry reforming of methane

Rivas, Maria Elena; Fierro, J.L.G.; Goldwasser, Mireya R.; Pietri, E.; Pérez-Zurita, M.J.; Griboval-Constant, Anne; Leclercq, G.

doi:10.1016/j.apcata.2008.03.023

Cited by 115 publications

(68 citation statements)

References 40 publications

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“…Valorization of natural gas could be carried out by its transformation to syngas, a mixture of hydrogen and carbon monoxide which is a feedstock to more valuable products, by means of methane reforming, major component of natural gas, through several reactions such as steam reforming, partial oxidation, auto-thermal reforming and combine and dry reforming [5][6][7][8]. The dry reforming has been proposed as an important reaction especially for its environmental quality, due to the reduction of green house gas emissions.…”

Section: Introductionmentioning

confidence: 99%

“…The dry reforming has been proposed as an important reaction especially for its environmental quality, due to the reduction of green house gas emissions. In addition, the H 2 /CO ratio obtained by CO 2 reforming of methane is more convenient for further applications [5][6][7][8][9]. A low H 2 /CO ratio favors the methanol to gasoline process for ethane, propane and aromatics from methanol and oxo-synthesis to alcohols.…”

Section: Introductionmentioning

confidence: 99%

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Ni–Nb-Based Mixed Oxides Precursors for the Dry Reforming of Methane

et al. 2011

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Perovskite-related mixed-oxides based on La Ni Nb and La Sr Ni Nb were synthesized by the auto combustion method to use as precursors materials for the catalytic reforming of methane at 700 8C, atmospheric pressure, CH 4 :CO 2 = 1:1. LaNiO 3 and LaNbO 4 were used as reference. XRD analysis show that the synthesis method produce a new series of precursor family formed by a mixture of oxides where Ni crystallized as part of a perovskite and Ruddlesden-Popper structure while Nb formed lanthanum orthoniobate LaNbO 4 , a scheelite-type structure alternating with oxide layers, with phase distribution depending on niobium content. For Nb (x B 0.3) Ni crystallizes as LaNiO 3 perovskite-type oxide while for Nb (x C 0.7) it forms mainly the orthoniobate phase LaNbO 4 a scheelite-type structure. At higher calcined temperatures (*1100°C) La 2 Ni 0.8 Nb 0.2 O 4 was formed with a Ruddlesden-Popper structure consisting of three perovskite type layers along the c-axis alternating with a layer of the rock salt type phase. TEM analysis showed the presence of cubic particles with sizes varying between 5 and 60 nm depending on the extent of substitution of Ni by Nb. Reduction of the perovskite-related precursor oxides produced a series of Ni 0 /La 2 O 3 -NbOx oxides with high metallic dispersion which favors the activity and stability of the catalysts. Introduction of doping quantities of Sr into LaNi 0.8 Nb 0.2 O 3±k structure produced a mixture of oxides with Sr dissolved in the lanthanum orthoniobate LaNbO 4 scheelite-type structure due to the similarity of ionic radii of La and Sr. Under the reaction conditions conversions near the thermodynamic equilibrium were attained which remains for long periods of time assessing the stability of the synthesized catalysts.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ni–Nb-Based Mixed Oxides Precursors for the Dry Reforming of Methane

et al. 2011

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“…La mayoría de las síntesis industriales de polvos para aplicación en cerámicas se obtiene por medio del método cerámico tradicional o reacción en estado sólido, también llamada de mezcla de óxidos (Yang et al, 2003;Ikeguche et al, 2005;Casanova et al, 2004;Liu et al, 2000;Teraoka et al, 2002). Entre los varios métodos de síntesis encontrados en la literatura, podemos citar: evaporation by dryness (Teraoka et al, 1988;Yaremchenlo y Kharton, 1999), método Pechini (Waller et al, 1996;), sol-gel (Vargas et al, 2007), técnicas de los citratos (Shao et al, 2000;Dong et al, 2001;Tong et al, 2002), creación de complejo combinando EDTA-citrato (Shao et al, 2001;Ikeguchi et al, 2003;2005;, co-precipitación (Oliveira et al;Rivas et al, 2008;Ouaguenouni et al, 2009;Tanabe Y Assaf, 2009). …”

Section: Introductionunclassified

Síntesis y Refinado por el Método Rietveld de la fase perovsquita obtenida a partir del Método de Co-precipitación vía Oxalato

et al. 2011

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ResumenMaterial cerámico del tipo perovisquita SrCo 0,8 Fe 0,2 O 3-δ fue sintetizado usando el método de coprecipitación en medio oxalato. Durante los análisis térmico-gravimétrico y térmico-diferencial (TG/DTA) se verificó que independientemente de la naturaleza del reactivo o agente precipitante adoptado en la síntesis del precursor, la curva termogravimétrica presenta tres etapas, con pérdida de masa total de aproximadamente el 40 %. Mediante difracción de rayos X se verificó que el tamaño medio del cristalito fue de aproximadamente 77,22 nm utilizando nitrato de Hierro III, casi un 83 % superior al obtenido usando oxalato de Hierro III (42,23 nm). Sin embargo, la variación del agente precipitante no afectó prácticamente al tamaño mediano de cristalino (42,95 nm y 42,23 nm). El material presenta isotermas de tipo II, con una superficie específica de aproximadamente 4,41m 2 g -1 . Palabras clave: perovsquita, método co-precipitación, oxalato, refinamiento Rietveld Synthesis and Refining by Rietveld Method of the perovskite phase obtained using Oxalate Coprecipitation Method AbstractPowders of perovskite SrCo 0.8 Fe 0.2 O 3-δ were synthesized using oxalate co-precipitation method. According to the thermal gravimetry and differential thermal analysis (TG/DTA), total mass loss was 40 % corresponding to three different steps and the precipitant agent as well the starting chemical elements have no influence on the process. Perovskite phase was identified by x-ray diffraction and the average crystallite size was 77.22 nm using iron nitrate (III) as starting material while 42.23 nm were obtained using iron oxalate (III). Ammonium oxalate and equimolar mixtures of ammonium oxalate and oxalic acid were used as precipitant agents and the results shown that these reactants have no influence on the average crystallite size (42.95 nm and 42.23 nm). The material presents isotherms of type II, with especific surface of approximately 4,41m 2 g -1 .

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“…Many investigations on the catalyst design and development for DRM have been focused on screening a new catalyst to reach higher activity and enhanced stability toward sintering, carbon deposition (coking) and metal oxidation [9][10][11][12][13][14]. However, CO 2 reforming of methane has not yet been implemented in the industry because so far there are no active, economic catalysts available and the current development aims to develop a catalyst with high carbon resistance [15].…”

Section: Introductionmentioning

confidence: 99%

Ni catalysts with different promoters supported on zeolite for dry reforming of methane

et al. 2015

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Dry reforming of methane (DRM) is considered a high endothermic reaction with operating temperatures between 700 and 1000°C to achieve high equilibrium conversion of CH 4 and CO 2 to the syngas (H 2 and CO). The conventional catalysts used for DRM are Ni-based catalysts. However, many of these catalysts suffer from the short longevity due to carbon deposition. This study aims to evaluate the effect of La and Ca as promoters for Nibased catalysts supported on two different zeolite supports, ZL (A) (BET surface area = 925 m 2 /g, SiO 2 /Al 2 O 3 mol ratio = 5.1), and ZL (B) (BET surface area = 730 m 2 /g, SiO 2 /Al 2 O 3 mol ratio = 12), for DRM. The physicochemical properties of the prepared catalysts were characterized with XRD, BET, TEM and TGA. These catalysts were tested for DRM in a microtubular reactor at reaction conditions of 700°C. The catalyst activity results show that the catalysts Ni/ZL (B) and Ca-Ni/ZL (B) give the highest methane conversion (60 %) with less time on stream stability compared with promoted Ni on ZL (A). In contrast, La-containing catalysts, La-Ni/ZL (B), show more time on stream stability with minimum carbon content for the spent catalyst indicating the enhancement of the promoters to the Ni/ZL (A) and (B), but with less catalytic activity performance in terms of methane and carbon dioxide conversions due to rapid catalyst deactivation.

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Structural features and performance of LaNi1−xRhxO3 system for the dry reforming of methane

Cited by 115 publications

References 40 publications

Ni–Nb-Based Mixed Oxides Precursors for the Dry Reforming of Methane

Ni–Nb-Based Mixed Oxides Precursors for the Dry Reforming of Methane

Síntesis y Refinado por el Método Rietveld de la fase perovsquita obtenida a partir del Método de Co-precipitación vía Oxalato

Ni catalysts with different promoters supported on zeolite for dry reforming of methane

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