Synthesis of Unidirectional Alumina Nanostructures without Added Organic Solvents

Kim, Hae Jin; Chung, Soo Hyun; Lee, Kyung Hee; Lee, Hee Cheon; Lee, Jae Sung

doi:10.1021/ja029494l

Cited by 151 publications

(84 citation statements)

References 11 publications

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“…[30] An analogous surfactant-templating approach was adopted for the synthesis of high-surface-area mesostructured boehmite and g-Al 2 O 3 under microwave processing conditions. [31] Surfactants have also been used to mediate the particle morphology of boehmite and mesoporous g-Al 2 O 3 to include hollow tubes [32] and fibers, [33] although these latter derivatives were not mesostructured.…”

mentioning

confidence: 99%

Mesostructured Forms of the Transition Phases η‐ and χ‐Al₂O₃

Zhang

Pinnavaia

2008

Angew Chem Int Ed

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mentioning

confidence: 99%

Mesostructured Forms of the Transition Phases η‐ and χ‐Al₂O₃

Zhang

Pinnavaia

2008

Angew Chem Int Ed

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“…According to the reports of Sobczyk et al (2004) and Lif et al (2007), the alumina surface contained different Brønsted and Lewis acidic sites. The interaction between ammonia and Brønsted acidic sites was considered weaker than that between ammonia and Lewis acid sites owing to the fact that ammonia desorption temperature over both Brønsted and Lewis acidic sites was 231 and 559 °C, respectively, in the NH 3 -TPD profile [ Figure 6(a)].…”

Section: Nh 3 -Tpd and Fourier Transform Infrared Analysismentioning

confidence: 93%

Mesoporous and Macroporous Alumina-Supported Nickel Adsorbents for Adsorptive Desulphurization of Commercial Diesel

Zheng

Wang

et al. 2015

Adsorption Science & Technology

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High-performance X%NiO x /Al 2 O 3 adsorbents were prepared using mesoporous and macroporous alumina for adsorptive desulphurization (ADS) of commercial diesel (total sulphur content, 150 ppmw) at atmospheric pressure. Among the synthesized adsorbents, the reduced mesoporous and macroporous 20%NiO x /Al 2 O 3 (Re20%NiO x /Al 2 O 3 ) presented the breakthrough capacity of 1.47 mg-S/g-sorbent with sulphur level of 10 ppmw. The ultra-deep desulphurization properties for two adsorbents were evaluated using simulated fuels. The adsorbent with macropores showed a superior desulphurization performance, and the existence of macropores remarkably increased its breakthrough capacity as well as improved the space steric hindrance effect. The adsorbents synthesized were characterized by nitrogen adsorption isotherms (BET), X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, temperature-programmed reduction of hydrogen, temperature-programmed desorption of ammonia and Fourier transform infrared techniques. The results showed that the synthesized adsorbents were stable, contained acid sites, especially Lewis acid sites, which played an important role in ADS. Even after three cycles of regeneration, the organic sulphur-adsorption capacity of Re20%NiO x /Al 2 O 3 was more than 80%.

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“…With further aging, the nanosheets are shown to curl up forming the nanofibers. The morphology was seen to be preserved even after calcinations at 1200 o C [17,21,45,55].…”

Section: Hydrothermal and Sol Gel Processesmentioning

confidence: 99%

“…Many of the nanfibers have been produced using hydrothermal treatment, with or without surfactant, [18][19][20][21][22][23][24][25] and sol-gel [17,27] techniques of various alumina precursors, subsequent calcinations dehydrate the solid from the sol-gel solution produced by the hydrothermal process. The solid, which consists of naonfibrous boehmite, may be calcined to obtain thealumina nanofibers.…”

Section: Synthesis Of Alumina Nanofibersmentioning

confidence: 99%

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Synthesis of Alumina Nanofibers and Composites

Noordin¹,

Liew²

2010

Nanofibers

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IntroductionAlumina, Al 2 O 3 , is a ceramic metal oxide of great importance as building material, refractory material, electrical and heat insulator, attributed to its high strength, corrosion resistance, chemical stability, low thermal conductivity, and good electrical insulation. One phase of alumina, the -phase is widely used as catalyst, catalyst support and adsorbent because its high porosity and surface area. It is conventionally prepared by heating the hydrated trihydroxides, gibbsite and bayerite, to temperature of > 1000 o C to obtain the -alumina, corundum, a material with great hardness and low surface area. The trihydroxides, gibbsite, bayerite, both are Al(OH) 3. nH 2 O and the monohydroxyl oxide, boehmite, AlO(OH)·αH 2 O, have the monoclinic crystal structure with similar lattice parameters (a=0.866 nm, b=0.506 nm, c=0.983 nm, =94°34′ in boehmite, a=0.868 nm, b=0.507 nm, c=0.972 nm, =94°34′ in gibbsite, and a=0.867 nm, b=0.506 nm, c=0.942 nm, =90°26′ in bayerite [1,2]. In the process of heat treatment, the trihydroxide undergoes a series of transformations. It loses the water of hydration, then dehydroxalate at < 300 o C to form the monohydroxyl oxide boehmite, AlO(OH), which on further heating to increasingly higher temperatures, changes to the transition aluminas, including the -, -, -, and -phases, which then transform finally to the -form. These transition aluminas are crystalline solids with high porosity and surface areas as well as acidic and basic properties, which make them suitable as adsorbents, catalyst, catalyst support and fabricated into filtration membranes as well as used as fillers or components in polymer/ inorganic composite materials with enhanced mechanical properties. The conventional alumina as obtained are usually powder of particulates. These could be fabricated into alumina fibers by various method, through melt growth techniques including the internal crystallization method and extrusion, electrospraying [3] and electrospinning [4][5][6][7][8] have been developed for producing Al 2 O 3 fibers. The high surface areas of transition aluminas are due to the presence of pores. These pores are irregular in sizes and size distributions, and are mainly micropores of diameter less than 2 nm. Since the synthesis of mesoporous materials was first reported in the late 1980s , a number of methods for the synthesis of mesoporous alumina have been reported [8,9]. More recently, interest in nano-materials and nanotechnology has spurred a fury of investigations

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Synthesis of Unidirectional Alumina Nanostructures without Added Organic Solvents

Cited by 151 publications

References 11 publications

Mesostructured Forms of the Transition Phases η‐ and χ‐Al₂O₃

Mesostructured Forms of the Transition Phases η‐ and χ‐Al₂O₃

Mesoporous and Macroporous Alumina-Supported Nickel Adsorbents for Adsorptive Desulphurization of Commercial Diesel

Synthesis of Alumina Nanofibers and Composites

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Synthesis of Unidirectional Alumina Nanostructures without Added Organic Solvents

Cited by 151 publications

References 11 publications

Mesostructured Forms of the Transition Phases η‐ and χ‐Al2O3

Mesostructured Forms of the Transition Phases η‐ and χ‐Al2O3

Mesoporous and Macroporous Alumina-Supported Nickel Adsorbents for Adsorptive Desulphurization of Commercial Diesel

Synthesis of Alumina Nanofibers and Composites

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Mesostructured Forms of the Transition Phases η‐ and χ‐Al₂O₃

Mesostructured Forms of the Transition Phases η‐ and χ‐Al₂O₃