A General Route to Macroscopic Hierarchical 3D Nanowire Networks

Wang, Donghai; Luo, Hongmei; Kou, Rong; Gil, Maria P.; Xiao, Shuaigang; Golub, Vladimir; Yang, Zhenzhong; Brinker, C. Jeffrey; Lu, Yunfeng

doi:10.1002/anie.200460535

Cited by 134 publications

(85 citation statements)

References 22 publications

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“…The sol-gel procedure given by Wang et al [23] was modified in this study to prepare ZnO-SiO 2 catalysts in one pot synthesis approach. All chemicals were supplied by Sigma-Aldrich and Acro Inc.…”

Section: Catalyst Preparationmentioning

confidence: 99%

The catalytic reforming of bio-ethanol over SiO2 supported ZnO catalysts: The role of ZnO loading and the steam reforming of acetaldehyde

Şeker

2008

International Journal of Hydrogen Energy

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t r a c tIn this study, the activity and the product distributions of sol-gel made SiO 2 supported ZnO catalysts in the steam reforming of ethanol and acetaldehyde is presented as a function of ZnO loading and temperature. We show that although highly dispersed ZnO in SiO 2 (upto 50% ZnO loading) can be prepared using a single step sol-gel method, a precise control of crystallite size could not be achieved. From CO 2 TPD measurements, we found that the basic site densities of ZnO/SiO 2 catalysts stays o0:05 mmol=m 2 and do not increase linearly with ZnO loading. The highest basic site density among the catalysts occurs on pure ZnO.All ZnO/SiO 2 catalysts are active at 350 1C whereas pure ZnO catalyst is active at 450 1C.Iso-conversion activity tests show that ethanol steam reforming activities of the catalysts seem to be dependent on the ZnO crystallite size rather than the basic site density of the catalysts when the surface coverage of the basic site density is o0:32% but acetone is not formed only on catalysts with ZnO crystallite size o5 nm regardless of their basic site densities. Interestingly, we found that ethanol was mostly dehydrogenated to acetaldehyde and hydrogen although H 2 O/C 2 H 5 OH molar ratio in the feed was 12. CO was not also produced in the steam reforming of ethanol over all the catalysts. Acetone and propene are produced from acetaldehyde as observed in the steam reforming of acetaldehyde. The steam reforming of acetaldehyde as compared to its decomposition was found to be more favorable over the catalysts with small ZnO crystals, such as 30% and 50% ZnO catalysts.

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Section: Catalyst Preparationmentioning

confidence: 99%

The catalytic reforming of bio-ethanol over SiO2 supported ZnO catalysts: The role of ZnO loading and the steam reforming of acetaldehyde

Şeker

2008

International Journal of Hydrogen Energy

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“…[61] Other membranes also have been used as templates, such as nanochannel-array glass, [61] radiation track-etched mica, [62] mesoporous materials, [63][64][65][66][67] porous silicon obtained by electrochemical etching of silicon wafer, [68] zeolites, [69] and carbon nanotubes. [70,71] Among the commonly used templates, alumina membranes with uniform and parallel porous structure are prepared by anodic oxidation of aluminum sheet in solutions of sulfuric, oxalic, or phosphoric acids.…”

Section: Template Synthesismentioning

confidence: 99%

Oriented Nanostructures for Energy Conversion and Storage

et al. 2008

Self Cite

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Recently, the role of nanostructured materials in addressing the challenges in energy and natural resources has attracted wide attention. In particular, oriented nanostructures demonstrate promising properties for energy harvesting, conversion, and storage. In this Review, we highlight the synthesis and application of oriented nanostructures in a few key areas of energy technologies, namely photovoltaics, batteries, supercapacitors, and thermoelectrics. Although the applications differ from field to field, a common fundamental challenge is to improve the generation and transport of electrons and ions. We highlight the role of high surface area to maximize the surface activity and discuss the importance of optimum dimension and architecture, controlled pore channels, and alignment of the nanocrystalline phase to optimize the transport of electrons and ions. Finally, we discuss the challenges in attaining integrated architectures to achieve the desired performance. Brief background information is provided for the relevant technologies, but the emphasis is focused mainly on the nanoscale effects of mostly inorganic-based materials and devices.

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“…Such unique structure imparts extraordinary properties and tremendous applications such as energy storage, catalysis, sensing, thermal insulation or thermal management, absorption, air-water purification, etc. [1][2][3][4][5][6][7][8][9][10][11][12] Therefore, aerogel structures from various types of materials are highly desirable, and significant efforts have been devoted to these materials. Aerogels are usually obtained from wet gels where the liquid (water or alcohols) is removed the resulting aerogels demonstrated potential as electrodes for Li-air battery and interesting magnetic response, respectively.…”

Section: Introductionmentioning

confidence: 99%

M13 Virus Aerogels as a Scaffold for Functional Inorganic Materials

Jung

et al. 2016

Adv Funct Materials

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1 of 8) 1603203 via either supercritical drying or freeze drying to prevent the collapse of the network structure by the surface tension of the liquid during drying process. To form a wet gel, a condensation mechanism (such as a cross-linking reaction) in the liquid is typically required, for example, sol-gel chemistry has been used to develop oxide-based aerogels such as SiO 2 -or TiO 2 aerogels, [13][14][15] aldol condensation has been used to develop resorcinol-formaldehyde polymer and carbon aerogels, [16][17][18] nanoparticle condensation by rapid cap removal has been used to develop semiconducting metal chalcogenide aerogels, [19,20] etc. The particular condensation reactions limit the types of materials that can be generated in the aerogel form. We have previously developed a methodology to physically assemble 1D nanowires or 2D nanosheets into an interconnected network from solution during their concentration increase (either by concentrating of suspension via solvent evaporation or by the continuous growth of nanowires out of a precursor solution). [21][22][23] This methodology requires no particular crosslinking reaction only relies on the van der Waals interaction, and works well when there is shape anisotropy (thus it will be termed shape anisotropy methodology, SAI in this work). It has been used to significantly widen the range of material types for aerogel structures: pristine carbon nanotube, MnO 2 , Ag, Cu, Si nanowire and pristine graphene, hexagonal boron nitride (hBN), and MoS 2 nanosheet aerogels without any cross-linking agents have been demonstrated for the first time providing excellent properties and interesting applications. [21] In this work, we investigated the SAI aerogel formation using biological molecules, M13 viruses. M13 virus is a filamentous bacteriophage which is ≈880 nm in length and ≈6.6 nm in diameter (with very low density of 0.91 g cm −3 calculated from molecular weight of 16.4 MDa [24] ). This nanowire shape makes it a very good candidate for the gel and aerogel formation using the SAI strategy. Using M13 virus freestanding extremely lightweight (<5 mg cm −3 ) 3D bulk structures can be obtained with excellent mechanical properties for the first time. Furthermore, as the M13 virus has been used as templates for versatile nanomaterial assembly, we have also investigated the SAI aerogel formation using inorganic-nanoparticle-complexed M13 virus. Ruthenium (Ru) and cobalt ferrite (CoFe 2 O 4 ) are used as two example materials in this work (one represent the example of mono-and the other represent multi-inorganic components),The filamentous M13 viruses are widely used as a bio-template to assemble many different functional structures. In this work, based on its shape anisotropy, reasonable aspect ratio (length to diameter of ≈130), and low density, freestanding, bulk 3D aerogels are assembled from M13 for the first time. These ultralight porous structures demonstrate excellent mechanical properties with elastic behavior up to 90% compression. Furthermore, as the genome of M1...

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A General Route to Macroscopic Hierarchical 3D Nanowire Networks

Cited by 134 publications

References 22 publications

The catalytic reforming of bio-ethanol over SiO2 supported ZnO catalysts: The role of ZnO loading and the steam reforming of acetaldehyde

The catalytic reforming of bio-ethanol over SiO2 supported ZnO catalysts: The role of ZnO loading and the steam reforming of acetaldehyde

Oriented Nanostructures for Energy Conversion and Storage

M13 Virus Aerogels as a Scaffold for Functional Inorganic Materials

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