Topic
Barium chromate
About: Barium chromate is a research topic. Over the lifetime, 194 publications have been published within this topic receiving 2381 citations.
Papers published on a yearly basis
1 / 2
Papers
TL;DR: In this paper, the interfacial activity of reverse micelles and microemulsions is exploited to couple nanoparticle synthesis and self-assembly over a range of length scales to produce materials with complex organization arising from the interdigitation of surfactant molecules attached to specific nanoparticle crystal faces.
Abstract: Colloidal inorganic nanoparticles have size-dependent optical, optoelectronic and material properties that are expected to lead to superstructures with a range of practical applications1,2. Discrete nanoparticles with controlled chemical composition and size distribution are readily synthesized using reverse micelles and microemulsions as confined reaction media3,4,5, but their assembly into well-defined superstructures amenable to practical use remains a difficult and demanding task. This usually requires the initial synthesis of spherical nanoparticles, followed by further processing such as solvent evaporation6,7,8, molecular cross-linking9,10,11,12,13,14 or template-patterning15,16,17,18. Here we report that the interfacial activity of reverse micelles and microemulsions can be exploited to couple nanoparticle synthesis and self-assembly over a range of length scales to produce materials with complex organization arising from the interdigitation of surfactant molecules attached to specific nanoparticle crystal faces. We demonstrate this principle by producing three different barium chromate nanostructures—linear chains, rectangular superlattices and long filaments—as a function of reactant molar ratio, which in turn is controlled by fusing reverse micelles and microemulsion droplets containing fixed concentrations of barium and chromate ions, respectively. If suitable soluble precursors and amphiphiles with headgroups complementary to the crystal surface of the nanoparticle target are available, it should be possible to extend our approach to the facile production of one-dimensional ‘wires’ and higher-order colloidal architectures made of metals and semiconductors.
1,368 citations
TL;DR: The results demonstrate that the integration of DHBCs, taking advantage of the experimental conditions such as crystallization sites, temperature, pH, and reactant concentration, will extend the possibilities for controlling the shape, size, and microstructures of the inorganic crystals by means of a simple mineralization process.
Abstract: A systematic morphosynthesis of barium chromate particles has been performed by using double-hydrophilic block copolymers (DHBCs), which consist of a hydrophilic solvating block and a hydrophilic binding block, as crystal growth modifiers to direct the controlled precipitation of barium chromate from aqueous solution. Several kinds of DHBCs with different functional groups COOH, PO3H2, SO3H, SH as well as PEG-poly(aminoamine) block-dendrimer copolymers were explored for crystallization and morphology control of barium chromate. Well-defined morphologies of BaCrO4 particles can be produced, such as more or less dendritic X-shaped, elongated X-shaped, or rodlike particles, flower-like plates, ellipsoids, spheres, nanofiber bundles, nanofibers, and other more complex morphologies. In the presence of the phosphonated copolymer PEG-b-PMAA-PO3H2 (degree of phosphonation: 21 %) at pH 5, large conelike bundles of nanofibers ranging from 10 to 20 nm in diameter with lengths up to 150 μm can be produced at room temperature, whereas replacement of the covalently bound phosphonate groups by the ionic salt analogue dopant fails to produce this structure, indicating the importance of the functional polymer block structures. The time-resolved formation process of the bundles of nanofibres was investigated, showing a remarkable self-similarity. At temperatures higher than 50 °C, in plastic flasks or when undergoing continuous stirring, only ellipsoids or nearly spherical particles can be obtained. This shows that the fiber formation relies on heterogeneous nucleation and is in agreement with a recently published mechanism where fiber formation is due to the vectorially directed self-assembly of primary particles. Our results demonstrate that the integration of DHBCs, taking advantage of the experimental conditions such as crystallization sites, temperature, pH, and reactant concentration, will extend the possibilities for controlling the shape, size, and microstructures of the inorganic crystals by means of a simple mineralization process.
146 citations
76 citations
TL;DR: In this article, a kinetic study of the ethanol dehydrogenation to ethyl acetate on a copper/copper-chromite catalyst has been performed, where the used catalyst, in cylindrical pellets, contained also alumina as a support and barium chromate as a promoter.
66 citations
TL;DR: In this article, epoxy-zirconate sol-gel coatings are used as barrier layers in complex coating systems, and experiments were performed to verify that these coatings can be used for barrier layers.
64 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 4 |
| 2020 | 4 |
| 2019 | 6 |
| 2018 | 8 |
| 2017 | 5 |
| 2016 | 9 |