Alumina ceramic foams as catalyst supports

Behravesh, Erfan; Hupa, Leena; Salmi, Tapio; Murzin, Dmitry Yu.

doi:10.1039/9781782626855-00028

Cited by 6 publications

(11 citation statements)

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“…The results of density, porosity, average strut thickness, average pore size (face diameter) and compressive strength of are listed in Table 1. The obtained results of the compressive strength are consistent with previous findings [38,39]. As can be seen from data shown in Table 1, there were no significant differences in the morphological properties and compressive strength between Al 2 O 3 foam substrate and TiO 2 -coated Al 2 O 3 foam.…”

Section: Properties Of Al 2 O 3 Foam Substrate and Tio 2 -Coated Al 2supporting

confidence: 91%

Titania-Coated Alumina Foam Photocatalyst for Memantine Degradation Derived by Replica Method and Sol-Gel Reaction

et al. 2020

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In the present work, alumina (Al2O3) foam was prepared by the replica method where a polyurethane (PU) foam (30 pores per inch (ppi)) template was impregnated with a 60 wt.% Al2O3 suspension. Sintered Al2O3 foam was used as substrate for the deposition of sol-gel derived titania (TiO2) film using dip coating. For the preparation of TiO2 sol, titanium(IV) isopropoxide (Ti-iPrOH) was used as the precursor. The common problem of qualification and quantification of a crystalline coating on a highly porous 3D substrate with an uneven surface was addressed using a combination of different structural characterization methods. Using Powder X-ray Diffraction (PXRD) and synchrotron Grazing Incidence X-ray Diffraction (GIXRD) on bulk and powdered Al2O3 foam and TiO2-coated Al2O3 foam samples, it was determined Al2O3 foam crystallizes to corundum and coating to anatase, which was also confirmed by Fourier Transformed Infrared Spectroscopy (FTIR). Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM/EDS) revealed the structural and microstructural properties of the substrate and coating. Differential Thermal Analysis (DTA) and Thermogravimetric Analysis (TGA) were used to clarify the evolution of the porous microstructure. The Al2O3-TiO2 composite was evaluated as a photocatalyst candidate for the degradation of the micropollutant medication memantine. The degradation rate was monitored using a light-emitting diode (LED) lamp operating at electromagnetic (EM) wavelength of 365 nm. The photocatalytic activity of sol-gel-derived TiO2 film immobilized on the Al2O3 foam was compared with commercially available TiO2 nanoparticles, P25-Degussa, in the form of a suspension. The levels of memantine were monitored by High-Performance Liquid Chromatography–Tandem Mass Spectrometry (HPLC–MS/MS). The efficiency and rate of the memantine photodegradation by suspended TiO2 nanoparticles is higher than the TiO2-coated Al2O3 foam. But, from the practical point of view, TiO2-coated Al2O3 foam is more appropriate as a valuable photocatalytic composite material.

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Section: Properties Of Al 2 O 3 Foam Substrate and Tio 2 -Coated Al 2supporting

confidence: 91%

Titania-Coated Alumina Foam Photocatalyst for Memantine Degradation Derived by Replica Method and Sol-Gel Reaction

et al. 2020

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“…This is because AF prepared from the alumina slurries contains tiny impurities, such as MgO and TiO 2 , thus contributing to more stray peaks in the XRD images of AF. 22 The diameter distribution of the spherical Al 2 O 3 was investigated by using a particle size analyzer (Figure 2k,l), showing average sizes of about 5 and 40 μm. Figure 2m shows the cross-section image of epoxy resin after curing.…”

Section: Resultsmentioning

confidence: 99%

“…21 Alumina foam (AF), synthesized via combining polyurethane (PU) foaming with alumina-based ceramic powders with sintering technology at an elevated temperature, is a three-dimensional (3D) grid structure with interconnected pores. 22 It can serve as a host for the combination of many polymers and various thermally conductive fillers within the interstices of the framework, using it to design composite materials with excellent thermal properties. 23 A combination of Al 2 O 3 powders and AF can potentially lead to the reduction of the thermal contact resistance mentioned above, which enables AF/Al 2 O 3 as a desirable hybrid filler for thermal conductivity composites.…”

Section: Introductionmentioning

confidence: 99%

Combining Alumina Particles with Three-Dimensional Alumina Foam for High Thermally Conductive Epoxy Composites

Wang

Wei

et al. 2020

ACS Appl. Polym. Mater.

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Ceramic/polymer composite with a high thermal conductivity is a candidate of insulating materials for electronic packaging. However, traditional polymer composites filled with alumina (Al2O3) powders present limited enhancement in thermal conductivity even at a high loading due to thermal resistance on the filler/filler and filler/matrix interfaces. Herein, a contiguous 3D network of alumina foam (AF) filled with different diameters of Al2O3 microparticles via vacuum-assisted filtration proves to be a promising filler structure for thermal conductivity composites. The fabricated epoxy/AF/Al2O3 composite exhibits a high thermal conductivity of 4.1 W/mK and a significant thermal conductivity enhancement (TCE) of 2097%. Further study reveals a prominent synergistic effect between the 3D interconnected AF and Al2O3 microparticles, which plays a critical role in the formation of thermal percolation networks to promote thermal conductivity dramatically. Meanwhile, compared to previous reports, the composite resulted in a lower coefficient of thermal expansion (CTE) than those of most epoxy-based composites, showing great potential for heat conduction applications in microelectronics. This result paves an effective way of developing epoxy composites with high thermal conductivity in electronic packaging applications.

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“…However, there is a limited description of the use of chitosan nanofibrils to template alumina materials as there are only two reports, of chitin-templated mesoporous alumina and chitosan-templated alumina microspheres . Many papers have reported the preparation of alumina catalyst supports, ,− but there are very few investigations of making γ-Al 2 O 3 aerogel-like materials. , Here, we report a new synthetic approach to lightweight γ-Al 2 O 3 aerogels by biotemplating with chitosan nanofibrils. Unlike previous acetic acid-based methods, our new approach is based on aqueous solutions of Al 3+ .…”

mentioning

confidence: 96%

“…Aluminum oxide (Al 2 O 3 ) aerogels are promising porous materials, useful as catalyst supports, thermal insulators, and absorptive filters because of their amphoteric surface sites and heat corrosion resistance. , The crystallinity, nanoscale, and stability of the alumina aerogels are keys to improving their performance. Among different alumina structures known, gamma (γ)-Al 2 O 3 is widely used as an active catalyst and catalyst support due to uncoordinated Al 3+ centers creating electronic defects at the surface. − For example, Mrabet et al synthesized γ-Al 2 O 3 nanocrystals to design highly active Ag/γ-Al 2 O 3 catalysts for removal of toxic NOx gases.…”

mentioning

confidence: 99%

Biotemplated Lightweight γ-Alumina Aerogels

et al. 2018

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We present the biotemplating of γ-Al 2 O 3 aerogels with chitosan nanofibrils. Aluminum−chitosan interactions cause the swelling of iridescent chitosan structures into helicoidal hydrogels and the subsequent aqueous dissolution of swollen fibrils to form Al− chitosan solutions. Viscous aqueous solutions of Al 3+ −chitosan hybrid nanofibers were freeze-dried to give lightweight cotton-like aerogels. Homogeneous incorporation of Al 3+ ions into chitosan yields water-soluble nanofibrils that can serve as polymeric templates to support Al 3+ ions in the aerogel composites. We investigated thermal removal of chitosan in the composites to obtain lightweight γ-Al 2 O 3 nanocrystal aerogels that retain the weblike fiber networks of the chitosan template. These biotemplated alumina aerogel materials are promising candidates for catalyst supports and thermal insulation.

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Alumina ceramic foams as catalyst supports

Cited by 6 publications

References 0 publications

Titania-Coated Alumina Foam Photocatalyst for Memantine Degradation Derived by Replica Method and Sol-Gel Reaction

Titania-Coated Alumina Foam Photocatalyst for Memantine Degradation Derived by Replica Method and Sol-Gel Reaction

Combining Alumina Particles with Three-Dimensional Alumina Foam for High Thermally Conductive Epoxy Composites

Biotemplated Lightweight γ-Alumina Aerogels

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