https://www.tandfonline.com/doi/pdf/10.1088/1468-6996/9/3/035004

Enhanced bioactivity of ZnO nanoparticles?an antimicrobial study

The influence of the choice of complexing ligand, zinc counter-ion, pH, ionic strength, supersaturation, deposition time and substrate on the nature of ZnO films grown from chemical baths (CBD) are discussed. There are significant differences between CBD and similar routes such as hydrothermal methods for ZnO films. Modelling of speciation and experimental results suggest that acicular ZnO morphologies are best obtained by limiting the concentration of one of either Zn2+ or OH− in the presence of a large excess of the other. The presence of a prior ZnO layer can facilitate nucleation at lower levels of supersaturation and enable size tailoring of ZnO columns. The point at which the substrate is introduced into the bath is crucial and can lead to a significant difference in both the width of the rods and optical transparency of the films. HR-TEM has yielded important structural information and a growth mechanism for single crystalline ZnO rods by CBD is described for the first time.

Understanding the factors that govern the deposition and morphology of thin films of ZnO from aqueous solution

We review two strategies for growing ZnO nanowires from zinc salts in aqueous and organic solvents. Wire arrays with diameters in the nanoscale regime can be grown in an aqueous solution of zinc nitrate and hexamethylenetetramine. With the addition of poly(ethylenimine), the lengths of the wires have been increased to 25 μm with aspect ratios over 125. Additionally, these arrays were made vertical by nucleating the wires from oriented ZnO nanocrystals. ZnO nanowire bundles have been produced by decomposing zinc acetate in trioctylamine. By the addition of a metal salt to the solution, the ZnO wires can be doped with a range of transition metals. Specifically, ZnO nanowires were homogeneously doped with cobalt and showed a marked deviation from paramagnetic behavior. We conclude by highlighting the use of these solution-grown nanowire arrays in dye-sensitized solar cells. The nanowire cells showed an improvement in the charge collection efficiency over traditional nanoparticle cells.

Solution-grown zinc oxide nanowires.

Molybdenum(VI) speciation in sulfidic waters; stability and lability of thiomolybdates

t. Chirality and Chiral Homogeneity in Nature 2. Biotic Theories 3. Abiotic Theories 3.1. Chance Mechanisms 3.1.1. Models for Spontaneous Symmetry Breaking 3.1.2. Spontaneous Resolution on Crystallization 3.1.3.Asymmetric Syntheses in Chiral Crystals 3.1.4. Asymmetric Adsorption and Catalysis on Quartz 3.1.5.Asymmetric Adsorption and Polymerization on Clays 3.1.6. Conclusions 3.2. Determinate Mechanisms 3.2.1. Regional and/or Temporal Processes 3.2.1.1.Electric, Magnetic and Gravitational Fields 3.2.1.2.Circularly Polarized Eight 3.2.1.2.1.Asymmetric Photoequilibration 3.2.1.2.2.Photochemical Asymmetric Synthesis 3.2.1.2.3.Asymmetric Photolysis 3.2.1.2.4.Sources of Circularly Polarized Eight 3.2.2. Universal Processes 3.2.2.l.The Violation of Parity 3.2.2.2.The Vester-Ulbricht (V-U) ttypothesis 3.2.2.3.Radioracemization 3.2.2.4.Direct Effects of Chiral Particles 3.2.2.4.1 .Electrons 3.2.2.4.2.Protons 3.2.2.4.3.Positrons and Muons 3.2.2.5.Weak Interactions, Neutral Currents and Parity Violating Energy Differences 3.2.3. Conclusions 4. The Amplification of Enantiomeric Excesses

The origin and amplification of biomolecular chirality

Synthetic analogues of the microporous minerals umbite (AM-2) and penkvilksite, polytype 2O (AM-3), have been prepared. The facile syntheses of two other titanosilicates, AM-1 and AM-4, have also been reported. AM-1 and the previously reported, layered titanosilicate known as JDF-L1 have been shown to have the same structure. AM-4 is a new microporous titanosilicate with a unique and unknown structure, containing eight different Na sites. All AM-n materials have been characterized by several techniques, viz. SEM, powder XRD, single- and triple-quantum 23Na and 29Si MAS NMR, water adsorption measurements, and TGA/DSC. AM-n materials are thermally stable up to ca. 600 °C. The dehydration−hydration processes seem to be reversible (or quasi reversible) for AM-1, -2, and -3 but not so for AM-4.

Synthesis and Structural Characterization of Microporous Umbite, Penkvilksite, and Other Titanosilicates

ZnO and ZnS powders were prepared from aqueous solutions of zinc salts in the presence of ethylenediamine or triethanolamine. The morphology of the powders was analysed by scanning electron microscopy and infrared spectroscopy. The effect of the experimental conditions upon the size and shape of the particles is described with a special emphasis on the role of the organic ligand.

/pdf/preparation-of-zinc-oxide-and-zinc-sulfide-powders-by-12b7vj3byo.pdf

Preparation of zinc oxide and zinc sulfide powders by controlled precipitation from aqueous solution

https://core.ac.uk/download/pdf/15565323.pdf

Júlio D. Pedrosa de Jesus

Papers

Synthesis and Structural Characterization of Microporous Umbite, Penkvilksite, and Other Titanosilicates

Preparation of zinc oxide and zinc sulfide powders by controlled precipitation from aqueous solution

Synthesis and characterization of tungsten trioxide powders prepared from tungstic acids

Synthetic hollow zinc oxide microparticles

Investigation of the thermal decomposition of some metal-substituted Keggin tungstophosphates