Formation of alumina nanofibers in carbon-containing coflow laminar diffusion flames

Guo, Bing; Yim, Hoon; Luo, Zhihan

doi:10.1016/j.jaerosci.2008.12.002

Cited by 6 publications

(5 citation statements)

References 8 publications

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“…Therefore the particle characteristics at various growth stages could be learned. Thermophoretic sampling has been used repeatedly in understanding particle evolution in flames (Dobbins and Megaridis 1987;Kennedy 2004, 2007;Guo et al 2009b;Mueller et al 2004).…”

Section: Thermophoretic Samplingmentioning

confidence: 99%

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Formation of Magnetic Fe_xO_y/Silica Core-Shell Particles in a One-Step Flame Aerosol Process

Guo¹,

Yim²,

Khasanov³

et al. 2010

Aerosol Science and Technology

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In this study, iron silicon oxide particles were generated in a onestep flame assisted spray pyrolysis (FASP) process using H 2 /air or H 2 /O 2 diffusion flames. A colloidal precursor solution was used, which contained dissolved iron nitrate and stably suspended silica nanoparticles. H 2 /air flames resulted in magnetic Fe x O y /silica core-shell particles. There was a correlation between particle size and particle structure; particles larger than 500 nm had the coreshell structure, but smaller particles had non-core-shell structures. H 2 /O 2 flames only resulted in nanoparticles that had non-coreshell structures. The core-shell particles had a iron oxide core that was hermetically enclosed in a uniform silica shell with a typical thickness of approximately 100 nm; they were superparamagnetic with a room-temperature saturation magnetization greater than 24 emu/g. Temperature history of the particles may be used to explain the correlation between flame type and particle structure. The correlation between particle size and structure may be due to size-dependent thermodynamic stability of the structures, or kinetics of heat and mass transfer. The results from this study suggest that micrometer sized iron oxide silica core-shell magnetic particles could be generated from a one-step flame aerosol process, but Fe x O y /silica nanoparticles (<100 nm) with the coreshell structure cannot be generated in a one-step flame aerosol process.

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Section: Thermophoretic Samplingmentioning

confidence: 99%

“…This depiction of particle growth does not include particle coagulation and coalescence. Nevertheless, this approach has been found useful for understanding metal oxide particle formation mechanisms in co-flow diffusion flames (Guo and Kennedy 2007;Guo et al 2009b).…”

Section: Correlation Of Flame Type and Particle Structurementioning

confidence: 99%

Formation of Magnetic Fe_xO_y/Silica Core-Shell Particles in a One-Step Flame Aerosol Process

Guo¹,

Yim²,

Khasanov³

et al. 2010

Aerosol Science and Technology

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“…Gels 2023, 9, x 12 of 25 of calcination at 850 °C, the amorphous alumina nanofibers were converted to γ-Al2O3 nanofibers. Guo et al [86] used trimethyl aluminum vapor as reactant by flame chemical deposition and formed alumina nanofibers with pure oxygen support in a carbon-containing concurrent diffusion flame. The prepared alumina nanofibers with diameters of 2-10 nm and lengths of 20-210 nm were non-crystalline.…”

Section: Other Preparation Methodsmentioning

confidence: 99%

Alumina Ceramic Nanofibers: An Overview of the Spinning Gel Preparation, Manufacturing Process, and Application

Meng

et al. 2023

Gels

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As an important inorganic material, alumina ceramic nanofibers have attracted more and more attention because of their excellent thermal stability, high melting point, low thermal conductivity, and good chemical stability. In this paper, the preparation conditions for alumina spinning gel, such as the experimental raw materials, spin finish aid, aging time, and so on, are briefly introduced. Then, various methods for preparing the alumina ceramic nanofibers are described, such as electrospinning, solution blow spinning, centrifugal spinning, and some other preparation processes. In addition, the application of alumina ceramic nanofibers in thermal insulation, high-temperature filtration, catalysis, energy storage, water restoration, sound absorption, bioengineering, and other fields are described. The wide application prospect of alumina ceramic nanofibers highlights its potential as an advanced functional material with various applications. This paper aims to provide readers with valuable insights into the design of alumina ceramic nanofibers and to explore their potential applications, contributing to the advancement of various technologies in the fields of energy, environment, and materials science.

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“…The nanofibers were formed in the region past the maximum temperature zone of the flame. Sufficiently high temperature may be due to the higher concentration of aluminum in the gas phase, while the presence carbon nanotubes or nanofibers may serve as templates or mediating agent for the alumina nanofibers formation [29,64].…”

Section: Flame Aerosol Methodsmentioning

confidence: 99%

“…Various routes including hydrothermal or solvothermal, sol-gel techniques, electrospinning and extrusion, template techniques [19,20], chemical vapor deposition in flame [30], and mercury mediated technique [29] have been developed for producing Al 2 O 3 nanofibers. 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.…”

Section: Synthesis Of Alumina Nanofibersmentioning

confidence: 99%

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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Formation of alumina nanofibers in carbon-containing coflow laminar diffusion flames

Cited by 6 publications

References 8 publications

Formation of Magnetic Fe_xO_y/Silica Core-Shell Particles in a One-Step Flame Aerosol Process

Formation of Magnetic Fe_xO_y/Silica Core-Shell Particles in a One-Step Flame Aerosol Process

Alumina Ceramic Nanofibers: An Overview of the Spinning Gel Preparation, Manufacturing Process, and Application

Synthesis of Alumina Nanofibers and Composites

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Formation of alumina nanofibers in carbon-containing coflow laminar diffusion flames

Cited by 6 publications

References 8 publications

Formation of Magnetic FexOy/Silica Core-Shell Particles in a One-Step Flame Aerosol Process

Formation of Magnetic FexOy/Silica Core-Shell Particles in a One-Step Flame Aerosol Process

Alumina Ceramic Nanofibers: An Overview of the Spinning Gel Preparation, Manufacturing Process, and Application

Synthesis of Alumina Nanofibers and Composites

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Product

Resources

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Formation of Magnetic Fe_xO_y/Silica Core-Shell Particles in a One-Step Flame Aerosol Process

Formation of Magnetic Fe_xO_y/Silica Core-Shell Particles in a One-Step Flame Aerosol Process