Microemulsion Approach to Non‐Agglomerated and Crystalline Nanomaterials

Abstract

A wide variety of different nanomaterials, including ZnO, (NH4)Y(C2O4)2·H2O, Y(OH)3, Y2O3, In2O3:Sn, CePO4:Tb, CaCO3, CuS, Co3[Co(CN)6]2, and K3[Co(NO2)6] are realized by a microemulsion approach. While heating the micellar system to reflux (200 to 215 °C), highly crystalline materials can be realized, which are still nanosized and do not agglomerate afterwards. Furthermore, a phase separation is initiated by the addition of diethylene glycol, which allows a facile removal of the nanomaterials by the application of low solvent quantitities, and again excludes agglomeration. Both aspects—the realization of highly crystalline materials and the facile separation of non‐agglomerated particles—represent a useful extension of microemulsion techniques. Besides the number and quality of the nanomaterials, the success of the experimental approach is further proven by the realization of physical properties that are restricted to crystalline materials. Namely, these are the bright colors of Co3[Co(CN)6]2 and K3[Co(NO2)6] as pigments, the electrical conductivity of In2O3:Sn (ITO), and the luminescence of CePO4:Tb.

In situ preparation and luminescent properties of LaPO4:Ce3+, Tb3+ nanoparticles and transparent LaPO4:Ce3+, Tb3+/PMMA nanocomposite

“…The low-resolution TEM image illustrates that the well-separated La 0.45 Ce 0.45 Tb 0.1 PO 4 nanoparticles are rodlike with widths of 2-6 nm and lengths of 10-55 nm. The rodlike structure of the as-prepared La 0.45 Ce 0.45 Tb 0.1 PO 4 is similar to those reported in literature [42,43], but with smaller grain size. As revealed by the high-resolution TEM image (Fig.…”

Multi-scale crystal engineering of metal organic frameworks

“…These first findings on metal-cyanide framework nanoparticles prompted the use of similar reverse microemulsion systems to tune the particle size and/or shape of other Prussian blue analogues, such as K [230][231][232], and metal-organic frameworks [184,[233][234][235][236].…”

Controllable Synthesis of Y2O3 Microstructures for Application in Cataluminescence Gas Sensing

“…[2] Yttrium oxide and its derivatives are attractive materials for their unique optical and electronic qualities and good catalytic properties towards many reactions, and have been used in a broad range of fields, such as optics and optoelectronics, [3] advanced ceramics, [4] chemical sensors, [5] catalysis, [6] and energy conversion and storage devices. [7] In the last decade, various shapes of solid materials, such as nanorods, nanotubes, nanoplates, microspheres, nanopolyhedra, and other polymorphic forms, have been synthesized by a variety of techniques such as solution-based sol-gel processing, [8] combustion, [9] microemulsion techniques, [10] co-precipitation, [11] hydrothermal/solvothermal synthesis, [12] thermolysis, [13] electrochemical methods, [14] solid/liquid-phase chemical routes, [15] and combinations thereof. Among the methods used in nanomaterials synthesis, owing to its great chemical flexibility and synthetic reliability, [16] hydrothermal synthesis has emerged as a powerful technology to prepare high-quality anisotropic architectures, such as nanorods, nanowires, nanobelts, nanotubes, and nanosheets, as well as even more complex fullerene-like Y 2 O 3 .…”