Characterization of nickel–alumina aerogels with high thermal stability

Osaki, Toshihiko; Mori, Toshiaki

doi:10.1016/j.jnoncrysol.2009.06.006

Cited by 21 publications

(3 citation statements)

References 31 publications

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“…Occasionally, this spinel is used as a support for Ni or other active metals such as rhodium. , The reforming activity of these reduced NiAl 2 O 4 catalysts is typically superior in comparison with other structurally similar phases such as CuAl 2 O 4 , NiFe 2 O 4 , or NiMn 2 O 4 . Usually a high-temperature reduction due to the stability of the crystalline NiAl 2 O 4 phase is necessary to efficiently extract nickel from the structure and thus obtain metallic crystallites with an adequate reforming activity. − …”

Section: Introductionmentioning

confidence: 99%

Behavior of Coprecipitated NiAl₂O₄/Al₂O₃ Catalysts for Low-Temperature Methane Steam Reforming

et al. 2014

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The suitability of the nickel aluminate phase as an effective precursor for producing highly active and stable Ni/ alumina catalysts was investigated in the steam reforming of methane with a H 2 O/CH 4 ratio of 3 in the 450−650°C temperature range. Particularly, the effect of the preparation route, including dissolution followed by crystallization, coimpregnation, and coprecipitation, for obtaining either bulk or alumina-supported samples was analyzed. A special attention was paid to correlating the characteristics of the calcined catalytic precursors with a Ni content varying between 17 and 33 wt %, namely, textural properties, composition, nature, and relative abundance of the existing nickel phases (NiAl 2 O 4 and NiO), as well as reducibility, with the Ni crystallite size, dispersion, and metallic surface area obtained after a severe high-temperature reduction step (850°C). A high intrinsic activity was found for the coprecipitated catalysts. This route was also effective for increasing the available metallic surface area. The best reforming performance (with a methane conversion of 78−80% and yield of hydrogen close to 1.63 at 650°C and 38 400 cm 3 CH 4 g −1 h −1 ) was achieved by a reduced alumina-supported (17 wt % Ni)NiAl 2 O 4 catalyst and the bulk NiAl 2 O 4 catalysts prepared by coprecipitation.

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Section: Introductionmentioning

confidence: 99%

Behavior of Coprecipitated NiAl₂O₄/Al₂O₃ Catalysts for Low-Temperature Methane Steam Reforming

et al. 2014

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“…The Rh3d5/2 and Rh3d3/2 peaks appearing after this reaction were relatively sharper than those observed after the H2 pre-reduction treatment. The peaks of Ni, NiO, and NiAl2O4 are associated with binding energies of 853 eV, 854 eV, and 856 eV, respectively [49], as shown in Figure 5b. However, the 5-hour reaction at DH and DHM fuels yielded indistinguishable Ni peaks.…”

Section: Catalyst Analysis Before and After Reaction In The Absence Amentioning

confidence: 95%

Enhanced Ni-Al-Based Catalysts and Influence of Aromatic Hydrocarbon for Autothermal Reforming of Diesel Surrogate Fuel

et al. 2019

Catalysts

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Aromatic hydrocarbons along with sulfur compounds in diesel fuel pose a significant threat to catalytic performances, due mainly to carbon deposition on the catalytic surface. In order to investigate the influence of an aromatic hydrocarbon on the autothermal reforming of diesel fuel, 1-methylnaphthalene (C11H10) was selected as an aromatic hydrocarbon. Two types of diesel surrogate fuel, i.e., DH (dodecane (C12H26) and hexadecane (C16H34) mixture) as well as DHM (DH fuel and C11H10 mixture) fuel, were prepared. A Rh-Al-based catalyst (R5A-I) was prepared using a conventional impregnation method. Various Ni-Al-based catalysts with Fe and Rh promoters were prepared via a polymer modified incipient method to improve the carbon coking resistance. These catalysts were tested under conditions of S/C = 1.17, O2/C = 0.24, 750 °C, and GHSV = 12,000 h-1 at DH or DHM fuel. R5A-I exhibited excellent catalytic performance in both DH and DHM fuels. However, carbon coking and sulfur poisoning resistance were observed in our previous study for the Ni-Al-based catalyst with the Fe promoter, which became deactivated with increasing reaction time at the DHM fuel. In the case of the Rh promoter addition to the Ni-Al-based catalysts, the catalytic performances decreased relatively slowly with increasing (from 1 wt.% (R1N50A) to 2 wt.% (R2N50A)) content of Rh2O3 at DHM fuel. The catalysts were analyzed via scanning electron microscopy combined with energy dispersive X-ray, X-ray diffraction, and X-ray photoelectron spectroscopy. Gas chromatography-mass spectrometry detected various types of hydrocarbons, e.g., ethylene (C2H4), with catalyst deactivation. The results revealed that, among the produced hydrocarbons, C2H4 played a major role in accelerating carbon deposition that blocks the reforming reaction. Therefore, Rh metal deserves consideration as a carbon coking inhibitor that prevents the negative effects of the C2H4 for autothermal reforming of diesel fuel in the presence of aromatic hydrocarbons.

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“…Shimizu et al [8] studied the reaction mechanism of propanol dehydrogenation on Ni/Al2O3 catalyst, and believed that Ni can activate C-H bond and promote the dehydrogenation reaction with the acid-base site on Al2O3. Osaki et al [10] reduced NiO-Al2O3 aerogels to obtain Ni/Al2O3 catalyst, TEM found that Ni particles with less than 6 nm were highly dispersed on the surface of Al2O3, which had a very good catalytic performance for CH4 reforming. Aluminum compounds supported with Ni catalysts were investigated in the De-HF of HFCs in this paper.…”

Section: Introductionmentioning

confidence: 99%

Catalytic Dehydrofluorination of Hydrofluoroalkanes to Fluorinated Olifein Over Ni/AlF₃ Catalysts

et al. 2018

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The hydrofluoric acid-resisting aluminum compounds (AlF3, AlPO4, AlN) supported with Ni catalyst were prepared by the wetness impregnation and tested for dehydrofluorination of hydrofluoroalkane to synthesize fluoroolefins. It is found that Ni/AlF3 catalyst has the best catalytic performance, CF3CFH2 conversion of 29.3% after the reaction at 430 °C for 30 h, CF2HCH3 conversion of 31.8% after the reaction at 250 °C for 30 h, respectively. Comparatively, dehydrofluorination temperature of CF3CFH2 is higher than CF2HCH3 over the aluminum compounds catalyst, and the activity of catalysts is related with Lewis acidity. For the aluminum compounds catalyst, addition of Ni had promoted the activity and stability of Lewis acidic catalysts, it is attributed to synergistic catalysis of Lewis acid sites and Ni.

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Characterization of nickel–alumina aerogels with high thermal stability

Cited by 21 publications

References 31 publications

Behavior of Coprecipitated NiAl₂O₄/Al₂O₃ Catalysts for Low-Temperature Methane Steam Reforming

Behavior of Coprecipitated NiAl₂O₄/Al₂O₃ Catalysts for Low-Temperature Methane Steam Reforming

Enhanced Ni-Al-Based Catalysts and Influence of Aromatic Hydrocarbon for Autothermal Reforming of Diesel Surrogate Fuel

Catalytic Dehydrofluorination of Hydrofluoroalkanes to Fluorinated Olifein Over Ni/AlF₃ Catalysts

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Characterization of nickel–alumina aerogels with high thermal stability

Cited by 21 publications

References 31 publications

Behavior of Coprecipitated NiAl2O4/Al2O3 Catalysts for Low-Temperature Methane Steam Reforming

Behavior of Coprecipitated NiAl2O4/Al2O3 Catalysts for Low-Temperature Methane Steam Reforming

Enhanced Ni-Al-Based Catalysts and Influence of Aromatic Hydrocarbon for Autothermal Reforming of Diesel Surrogate Fuel

Catalytic Dehydrofluorination of Hydrofluoroalkanes to Fluorinated Olifein Over Ni/AlF3 Catalysts

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Behavior of Coprecipitated NiAl₂O₄/Al₂O₃ Catalysts for Low-Temperature Methane Steam Reforming

Behavior of Coprecipitated NiAl₂O₄/Al₂O₃ Catalysts for Low-Temperature Methane Steam Reforming

Catalytic Dehydrofluorination of Hydrofluoroalkanes to Fluorinated Olifein Over Ni/AlF₃ Catalysts