Comparative Study of Mg/M(III) (M=Al, Ga, In) Layered Double Hydroxides Obtained by Coprecipitation and the Sol–Gel Method

Aramendía, M. A.

doi:10.1006/jssc.2002.9655

Cited by 116 publications

(55 citation statements)

References 30 publications

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“…The nitrogen adsorption/desorption isotherms of NiAl-R for the five solids exhibit type IV isotherms (Fig. 5) according to the International Union of Pure and Applied Chemistry (IUPAC classification), which are typical of mesoporous and slitshaped materials [44]. The samples also exhibit the hysteresis type H 2 which is typical of clay minerals either of cationic or anionic types such as hydrotalcites [45].…”

Section: Resultsmentioning

confidence: 96%

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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Section: Resultsmentioning

confidence: 96%

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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“…70°C, for 8 hours and then allowed to cool down overnight. NH 4 OH was added to maintain pH > 10. This cycle was repeated four times.…”

Section: Sample Preparationmentioning

confidence: 99%

Thermal Properties of Lauric- and Stearic Acid Intercalated Layered Double Hydroxides

Focke

Nhlapo

Moyo

et al. 2010

Molecular Crystals and Liquid Crystals

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. H O z was intercalated with lauric and stearic acid using a surfactant-assisted method. X-ray diffraction, thermal analysis and infrared spectroscopy confirmed that bilayer-intercalated compounds were formed and that the surfactant (sodium dodecyl sulfate) was not co-intercalated. These compounds shows interesting thermal behavior with two phase transformations observed at elevated temperatures. At temperatures that are significantly higher than the melting points of the corresponding free acids, the alkyl chains assume a disordered liquid-like state within the clay galleries. However, at even higher temperatures the materials become completely amorphous like true melts.

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“…Layered double hydroxides (LDHs) or hydrotalcite-like solids are of interest of these studies due to their unique properties to immobilize very wide range of cations (like, Li + , Ba 2+ , Mg 2+ , Fe 2+ , Ni 2+ , Co 2+ , Eu 3+ , Fe 3+ , Cr 3+ , Ga 3+ , Sc 3+ , Zr 4+ , etc.) [1][2][3][4][5][6][7][8][9] and especially due to their anion-exchange properties (substitution of I − , Br − , Cl − , OH − , CO 3 2− , SO 4 2− , Fe(CN) 6 4− , carboxylates, sulfonates or dicarboxylates C n H 2n (CO 2 − ) 2 , etc.) [10][11][12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Preparation, characterization and thermodynamic properties of Zr-containing Cl-bearing layered double hydroxides (LDHs)

2015

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Comparative Study of Mg/M(III) (M=Al, Ga, In) Layered Double Hydroxides Obtained by Coprecipitation and the Sol–Gel Method

Cited by 116 publications

References 30 publications

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

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

Thermal Properties of Lauric- and Stearic Acid Intercalated Layered Double Hydroxides

Preparation, characterization and thermodynamic properties of Zr-containing Cl-bearing layered double hydroxides (LDHs)

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