Zinc oxide nanoparticles, preparation

Figure 2. The mechanism for preparation of Nano ZnO-CHIT electrode and immobilization of ChOx onto NanoZnO-CHIT Nanocomposite, Reprinted from Analytica Chimica Acta, 616, R. Khan, A. Kaushik, P. R. Solanki, A.A. Ansari, M.K. Pandy, B.D. Malhotra, Zinc oxide nanoparticles -chitosan composite film for cholesterol biosensor, 209,Copyright( 2008) with permission fom Elsevier.

Recently, Kaneko et aL [252] reported a method in which reverse micelles were first prepared from the system NP-6 (hexaoxyethylene nonylphenyl ether)/ cyclohexane, containing zinc di-n-butoxide. An aqueous ammonia solution was added to it, causing precipitation. When ammonia was not added to the system, the product was a mixture of ZnO and Zn(OH)2- In keeping with some earlier reports of synthesis by other techniques [33], the wurtzite-type zinc oxide nanoparticles were rodlike. The length and width of the particles varied as a function of the [H20]/[NP-6] and [NH3]/[NP-6] ratios, as also the concentration of the butoxide. For example, with an optimum water/surfactant concentration ratio of 4 and [NH3]/[NP-6] = 0.5, the average length and width of the particles showed values of about 21 and 13 nm respectively. 

M.M. Abdelhady, Preparation and characterization of chitosan/zinc oxide nanoparticles for imparting antimicrobial and UV protection to cotton fabric. Int. J. Carbohydr. Chem. 2012, 1-6(2012). 

Kube M, Erler J, Peuker U, Schmidt C Thermal decomposition of ricinoUc-acid-stabilized zinc oxide nanoparticles studied by FTIR and NMR spectroscopy (in preparation)... 

Yumak T, Kuralay F, Erdem M, Sinag A, Erdem A, Abaci S (2011) Preparation and characterization of zinc oxide nanoparticles and their sensor applications for electrochemical monitoring of nucleic acid hybridization. Colloids Surf B 86 397-403... 

E. Tang, G.X. Cheng, X.L. Ma, Preparation of nano-ZnO/PMMA composite particles via grafting of the copolymer onto the surface of zinc oxide nanoparticles. Powder Technology 161(3) (2006) 209-214. 

Immobilizing DENs within a sol-gel matrix is another potential method for preparing new supported catalysts. PAMAM and PPI dendrimers can be added to sol-gel preparations of silicas " and zinc arsenates to template mesopores. In one early report, the dendrimer bound Cu + ions were added to sol-gel silica and calcined to yield supported copper oxide nanoparticles. Sol-gel chemistry can also be used to prepare titania supported Pd, Au, and Pd-Au nanoparticle catalysts. Aqueous solutions of Pd and Au DENs were added to titanium isopropoxide to coprecipitate the DENs with Ti02. Activation at 500°C resulted in particles approximately 4 nm in diameter. In this preparation, the PAMAM dendrimers served two roles, templating both nanoparticles and the pores of the titania support. 

Crystalline nanorings, literally closed circular nanoparticles with a hollow centre, were first prepared from zinc oxide in 2004 by a spontaneous self-coiling process from polar nanobelts.44 Semiconductor nanorings and indeed interestingly shaped nanoobjects in general, promise much in the way of applications as tools to probe fundamental physical phenomena and as nanoscale sensors, transducers, and resonators. 

Virion templates of TMV were also used in combination with different synthetic routes for CdS, PbS, and Fe oxide nanoparticles. Nanoparticle-virion tubules were prepared by reacting a buffered solution of TMV in CdCl2 (pH 7) or TMV in Pb(N03)2 (pH 5) with H2S gas. The formation of metal sulfide nanoparticles occurred over 6 hours as observed by a uniform coating of CdS and PbS nanocrystals on the TMV surface from TEM analysis. Selected area electron diffraction of the mineralized products indicated a zinc blende crystal stracture for CdS particles and a rock salt structure for single domain PbS nanocrystals. The iron oxide nanoparticles were mineralized by the TMV templates by the oxidative hydrolysis of an Fe VFe acidic solution with NaOH. Consequently, a mineral coating of irregular ferrihydrite particles grew on the surface to a thickness of 2 nm. 

One extensively studied material system among the nanocrystal-polymer blends is zinc oxide (ZnO) in combination with MDMO-PPV or P3HT [273-282]. Beek et al. presented the first polymer solar cells containing ZnO nanoparticles, reaching power conversion efficiencies of 1.6% [273]. In this case the nanoparticles were prepared separately and then intermixed with MDMO-PPV in solution. Shortly after this study the Janssen group presented another route to ZnO-polymer hybrid solar cells by forming the nanocrystals in situ inside the film by applying a precursor [274]. Here, diethylzinc served as the precursor and was spin cast in blends with MDMO-PPV. Process-... 

In addition to the above, preparation in w/o microemulsions of nanoparticles of various other types of compounds, viz. silica-coated iron oxide, Fe203-Ag nanocomposite, oxides of ytrium, erbium, neodymium, vanadium and cobalt, titanates of barium and lead, ferrites of barium, strontium, manganese, cobalt and zinc, oxide superconductors, aluminates, zirconium silicate, barium tungstate, phosphates of calcium, aluminium and zinc, carbonates of calcium and barium, sulphides of molybdenum and sodium, selenides of cadmium and silver etc. have been reported. Preparative sources and related elaboration can be found in [24]. 

In this paper, capabilities of a simple and low-cost synthesis method based on the pulsed discharge submerged in water for fabrication of zinc oxide nanopowders are discussed. This technique has the additional advantage of eliminating the need for high temperatures and for chemical precursors and it offers a good control over the particles size. The structural and optical properties of prepared nanoparticles have been studied and optimal conditions for preparation of high quality ZnO nanopowder without metallic zinc contamination have been found. 

Crystallization and reduction of sol-gel prepared zinc oxide films derived from zinc acetate by irradiation with an UV lamp (185 and 254 nm) was studied (Asakuma et al. 2003). UV irradiation induced the formation of hexagonal ZnO crystals from amorphous ZnO films preheated at 100 C, while irradiation of porous ZnO films preheated at 60 C led also to formation of metallic zinc. Composite ZnO/Cu and ZnO/Ag/Cu nanostructures were prepared via the photocatalytic reduction (wavelength 310-390 nm) of cuprous chloride and silver nitrate over the chemically prepared ZnO nanoparticles in aqueous solution (Shvalagin et al. 2004). Amorphous ZnO thin films were prepared... 

Mikrajuddin, Iskandar, F., Okuyama, K., and Shi, G.F., Stable photoluminescence of zinc oxide quantum dots in silica nanoparticles matrix prepared by the combined sol-gel and spray drying method, J. Appl. Phys., 89, 6431-6434, 2001. 

It may be desirable to lower the reaction temperatures required for highly crystalline particle formation to be achieved. Ito etal. have recently reported an esterification process which lowers the reaction temperatures to less than 230 °C for the preparation of an extensive range of oxide nanoparticles including indium oxide (10203), tin-doped 10303, iron oxide (y-Fe203), manganese oxide (Mo203), cobalt oxide (CoO) and zinc oxide (ZnO). Metal acetates are first heated in oleic acid to form the corresponding metal oleate, which then reacts with alcohol to provide an... 

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