Effect of supports and Ni crystal size on carbon formation and sintering during steam methane reforming

Christensen, Kjersti O.; Chen, D.; Lødeng, Rune; Holmén, Anders

doi:10.1016/j.apcata.2006.07.028

Cited by 383 publications

(223 citation statements)

References 53 publications

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“…For example, Cu-Mg-Al mixed oxides were found to be active and selective catalysts for the DeNOx process [3] and selective catalytic oxidation of ammonia to nitrogen and water vapor [7]. Hydrotalcite-based mixed metal oxides modified with nickel were effective catalysts of steam methane reforming [8], while iron containing hydrotalcites were recognized as precursors of effective catalysts for ethylbenzene dehydrogenation [9].…”

Section: Introductionmentioning

confidence: 99%

An influence of thermal treatment conditions of hydrotalcite-like materials on their catalytic activity in the process of N2O decomposition

Chmielarz

Rutkowska

Kuśtrowski

et al. 2011

J Therm Anal Calorim

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Hydrotalcite-like materials containing apart from magnesium and aluminum also copper, cobalt, nickel, and iron were prepared by a co-precipitation method. Thermal transformations of hydrotalcite-like materials were studied by thermal analysis methods as well as XRD, UV-vis-DRS, and XPS measurements of the samples calcined at various temperatures (600, 700, and 800°C). Calcined hydrotalcites, especially those containing cobalt and copper, were found to be active and selective catalysts of N 2 O decomposition. It was shown that an increase in the calcination temperature significantly activated the Co-containing catalysts. Promotion of the samples with potassium resulted in activation of the hydrotalcite-based catalysts.

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Section: Introductionmentioning

confidence: 99%

An influence of thermal treatment conditions of hydrotalcite-like materials on their catalytic activity in the process of N2O decomposition

Chmielarz

Rutkowska

Kuśtrowski

et al. 2011

J Therm Anal Calorim

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“…Other previously studied catalytic systems, such as those derived from layered double hydroxides (LDHs) that contain large surface areas, can result in the formation of homogeneous mixture of oxides with small crystal sizes. Reduction of LDHs prompts the formation of small, thermally stable, metal particles that can minimize the sintering of the nickel catalyst and enhance chemisorption of carbon dioxide [13], thus, avoiding the formation of coke [14,15].…”

Section: Introductionmentioning

confidence: 99%

Effect of the Ni/Al ratio of hydrotalcite-type catalysts on their performance in the methane dry reforming process

et al. 2015

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Hydrotalcite-type solids of the form NiAl-R, where R refers to the ratio of Ni to Al (R = 2, 3, 5, 8, and 10), were successfully synthesized following co-precipitation method at pH = 12. The obtained solids were calcined at 800°C, except for NiAl-R 2 where calcination was performed at temperatures ranging between 300 and 800°C. Following calcination, the resulting materials were evaluated for their catalytic activity and stability during the process of dry reforming of methane. Factors affecting the catalytic activity of the obtained materials such as the ratio R and calcination temperature were also studied. Prior to calcination, X-ray diffraction analyses clearly illustrated the typical hydrotalcite structure of the synthesized materials (when R B 5). On the other hand, calcination at various temperatures prompted decomposition of all solids to form NiO, with exception to NiAl-R 2 , which upon calcinations at 800°C was decomposed to form NiO and a second phase spinel containing NiAl 2 O 4 . The chemical composition of the obtained solids was determined by atomic absorption spectroscopy. Further characterization was performed using several techniques, including: surface area measurements (S BET ), scanning electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis. The reducibility of nickel species was studied via temperatureprogrammed reduction. The catalytic performance of the asprepared samples was studied for dry reforming of methane under atmospheric pressure at temperatures ranging between 400 and 700°C. The catalytic activity of the designed substances highlighted the importance of molar ratios i.e. Ni 2? / Al 3? on the success of the overall dry reforming of methane process. The catalytic activity of the synthesized materials was also found to be directly proportional to the ratio of Ni/ Al as well as the calcination temperature, with exception to NiAl-R 2 which was found to exhibit the highest activity of all. The latter observation was perhaps associated with the lower size of the crystalline particles in conjunction with the presence of a second phase containing NiAl 2 O 4 . In this study, it is shown that the calcination temperature has a significant effect on the catalytic property and the crystallite size of the metal.

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“…Nickel-based catalysts are apt to sinter under catalytic reforming conditions of high temperatures and in the presence of steam [38]. Severe carbon deposition could also be observed on the catalyst if the surface carbon species adsorbed on metal surface are not removed in time [39]. Carbon deposition over nickel-based catalysts is a fatal problem for the steam reforming of bio-ethanol.…”

Section: Methodsmentioning

confidence: 99%

Hydrogen Production by the Steam Reforming of Bio-Ethanol over Nickel-Based Catalysts for Fuel Cell Applications

Chen¹,

Xu²

2017

IJSGE

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Abstract:The bio-ethanol steam reforming over nickel-based catalysts when the temperature is within the range of 700 to 800 K is studied for fuel cell applications. The effect of operating conditions such as the temperature, space time, water-to-ethanol molar ratio, and oxygen-to-ethanol molar ratio on the product distribution is evaluated. The water-gas shift reaction is examined in the reforming process. Adjusting feed ratios to favor carbon removal from the surface is discussed in detail. It is shown that a nickel-supported-on-alumina catalyst completely converts bio-ethanol and high hydrogen yields are obtained. High temperatures and water-to-ethanol ratios can promote hydrogen production. There is no evidence that the water-gas shift reaction occurs over nickel-based catalysts. Carbon formation can be minimized by using high water-to-ethanol ratios. The presence of oxygen in the feed plays a favorable effect on the carbon deposition, but the carbon monoxide production is not reduced. There are several reaction pathways that could occur in the bio-ethanol steam reforming process, and the catalyst produces ethylene and acetaldehyde as intermediate products. The region of carbon formation depends on the temperature as well as the water-to-ethanol and oxygen-to-ethanol molar ratios. Finally, an overall reaction scheme as a function of temperature is proposed. The best catalysts appear to be those that are sufficiently basic to inhibit the dehydration of ethanol to ethylene, which subsequently polymerizes and causes coke formation.

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Effect of supports and Ni crystal size on carbon formation and sintering during steam methane reforming

Cited by 383 publications

References 53 publications

An influence of thermal treatment conditions of hydrotalcite-like materials on their catalytic activity in the process of N2O decomposition

An influence of thermal treatment conditions of hydrotalcite-like materials on their catalytic activity in the process of N2O decomposition

Effect of the Ni/Al ratio of hydrotalcite-type catalysts on their performance in the methane dry reforming process

Hydrogen Production by the Steam Reforming of Bio-Ethanol over Nickel-Based Catalysts for Fuel Cell Applications

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