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Metal Oxide Particles (metal + oxide_particle)

Distribution by Scientific Domains
Polymers and Materials Science57%
Chemistry42%

Selected Abstracts

Formation of Metal Oxide Particles in Atomic Layer Deposition During the Chemisorption of Metal Chlorides: A Review,

CHEMICAL VAPOR DEPOSITION, Issue 2 2005
L. Puurunen
Abstract As has been known for a decade, metal oxide particles can form in a single reaction of gaseous metal chlorides with solid oxides. This is an undesirable effect in the fabrication of thin films by atomic layer deposition (ALD). This work reviews the experimental results related to the metal oxide particle formation and the mechanisms suggested to account for it. The suggested mechanisms cannot explain the observations, but systematic analysis of the possible reaction paths delivers one reaction mechanism candidate, based on a reaction between surface chlorine groups and the hydroxyl groups of gaseous metal hydroxychloride intermediates. The consequences of the proposed mechanism are discussed. [source]

Self-Propagating Domino-like Reactions in Oxidized Graphite

ADVANCED FUNCTIONAL MATERIALS, Issue 17 2010
Franklin Kim
Abstract Graphite oxide (GO) has received extensive interest as a precursor for the bulk production of graphene-based materials. Here, the highly energetic nature of GO, noted from the self-propagating thermal deoxygenating reaction observed in solid state, is explored. Although the resulting graphene product is quite stable against combustion even in a natural gas flame, its thermal stability is significantly reduced when contaminated with potassium salt by-products left from GO synthesis. In particular, the contaminated GO becomes highly flammable. A gentle touch with a hot soldering iron can trigger violent, catastrophic, total combustion of such GO films, which poses a serious fire hazard. This highlights the need for efficient sample purification methods. Typically, purification of GO is hindered by its tendency to gelate as the pH value increases during rinsing. A two-step, acid,acetone washing procedure is found to be effective for suppressing gelation and thus facilitating purification. Salt-induced flammability is alarming for the fire safety of large-scale manufacturing, processing, and storage of GO materials. However, the energy released from the deoxygenation of GO can also be harnessed to drive new reactions for creating graphene-based hybrid materials. Through such domino-like reactions, graphene sheets decorated with metal and metal oxide particles are synthesized using GO as the in situ power source. Enhanced electrochemical capacitance is observed for graphene sheets loaded with RuO2 nanoparticles. [source]

Self-Propagating Domino-like Reactions in Oxidized Graphite

ADVANCED FUNCTIONAL MATERIALS, Issue 17 2010
Franklin Kim
Abstract Graphite oxide (GO) has received extensive interest as a precursor for the bulk production of graphene-based materials. Here, the highly energetic nature of GO, noted from the self-propagating thermal deoxygenating reaction observed in solid state, is explored. Although the resulting graphene product is quite stable against combustion even in a natural gas flame, its thermal stability is significantly reduced when contaminated with potassium salt by-products left from GO synthesis. In particular, the contaminated GO becomes highly flammable. A gentle touch with a hot soldering iron can trigger violent, catastrophic, total combustion of such GO films, which poses a serious fire hazard. This highlights the need for efficient sample purification methods. Typically, purification of GO is hindered by its tendency to gelate as the pH value increases during rinsing. A two-step, acid,acetone washing procedure is found to be effective for suppressing gelation and thus facilitating purification. Salt-induced flammability is alarming for the fire safety of large-scale manufacturing, processing, and storage of GO materials. However, the energy released from the deoxygenation of GO can also be harnessed to drive new reactions for creating graphene-based hybrid materials. Through such domino-like reactions, graphene sheets decorated with metal and metal oxide particles are synthesized using GO as the in situ power source. Enhanced electrochemical capacitance is observed for graphene sheets loaded with RuO2 nanoparticles. [source]

Formation of Metal Oxide Particles in Atomic Layer Deposition During the Chemisorption of Metal Chlorides: A Review,

CHEMICAL VAPOR DEPOSITION, Issue 2 2005
L. Puurunen
Abstract As has been known for a decade, metal oxide particles can form in a single reaction of gaseous metal chlorides with solid oxides. This is an undesirable effect in the fabrication of thin films by atomic layer deposition (ALD). This work reviews the experimental results related to the metal oxide particle formation and the mechanisms suggested to account for it. The suggested mechanisms cannot explain the observations, but systematic analysis of the possible reaction paths delivers one reaction mechanism candidate, based on a reaction between surface chlorine groups and the hydroxyl groups of gaseous metal hydroxychloride intermediates. The consequences of the proposed mechanism are discussed. [source]

Uniform Metal (Hydr)Oxide Particles from Water/Ionic Liquid Precursor (ILP) Mixtures

CHEMISTRY - A EUROPEAN JOURNAL, Issue 27 2008
Zhonghao Li Dr.
Abstract We have recently shown that the hydrated ionic liquid tetrabutylammonium hydroxide (TBAH) is an efficient ionic liquid precursor (ILP) for the fabrication of ZnO/carbohydrate materials (D. Mumalo-Djokic, W.,B. Stern, A. Taubert, Cryst. Growth Des.2008, 8, 330). The current paper shows that ZnO is just one example out of the large group of technologically important metal (hydr)oxides that can be made using TBAH. Simply by using different metal acetates as precursors in TBAH, it is possible to make a wide variety of metal (hydr)oxides with well-defined size, morphology, and chemical composition. It is also possible to dope metal oxide particles or to synthesize mixed metal oxide particles, and therefore to control properties like magnetism. [source]

Embedded Phases: A Way to Active and Stable Catalysts

CHEMSUSCHEM CHEMISTRY AND SUSTAINABILITY, ENERGY & MATERIALS, Issue 1 2010
Loredana De, Rogatis Dr.
Abstract Industrial catalysts are typically made of nanosized metal particles, carried by a solid support. The extremely small size of the particles maximizes the surface area exposed to the reactant, leading to higher reactivity. Moreover, the higher the number of metal atoms in contact with the support, the better the catalyst performance. In addition, peculiar properties have been observed for some metal/metal oxide particles of critical sizes. However, thermal stability of these nanostructures is limited by their size; smaller the particle size, the lower the thermal stability. The ability to fabricate and control the structure of nanoparticles allows to influence the resulting properties and, ultimately, to design stable catalysts with the desired characteristics. Tuning particle sizes provides the possibility to modulate the catalytic activity. Unique and unexpected properties have been observed by confining/embedding metal nanoparticles in inorganic channels or cavities, which indeed offers new opportunities for the design of advanced catalytic sytems. Innovation in catalyst design is a powerful tool in realizing the goals of more green, efficient and sustainable industrial processes. The present Review focuses on the catalytic performance of noble metal- and non precious metal-based embedded catalysts with respect to traditional impregnated systems. Emphasis is dedicated to the improved thermal stability of these nanostructures compared to conventional systems. [source]