Effect of lithium oxide dopants on electrophysical and sorption properties of zinc oxide

The effects of lithium oxide dopants (0.5–0.8 at. % Li) on the electrophysical and sorption properties of ZnO were studied in the temperature range from 150 °C to 410 °C. The introduction of lithium increases the activation energy of the conductivity of ZnO, decreases its conductivity, and increases the amount of S0₂ sorbed. Two forms of chemisorbed SO₂ (donor and acceptor) are observed on the surface.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1096–1100, May, 1996.     

Effect of antimony dopants on the sorption properties of SnO2

The effects of antimony modifying additive (0.15—0.50 at.% Sb) on the electrophysical and sorption properties of SnO₂ powders with a well developed specific surface were studied in the temperature range of 25—250 °C. Small amounts of antimony (0.15 at.%) increase the conductivity of SnO₂ containing SO₂ and CO chemisorbed in the temperature range of 25—100 °C. This makes this composition promising as a sensitive element of gas sensors.     

The effect of Fe2O3 dopants on electrophysical and sorption properties of ZnO

The effect of Fe₂O₃ dopants (0–0.8 mol.%) on ZnO conductivity and its chlorine chemisorption ability has been studied in the temperature range of 20–250 °C. Introduction of dopants increases the activation energy of ZnO conductivity and decreases the conductivity. The effective charge of the chemisorbed chlorine species as well as the strength of their bonding to the surface in samples containing Fe₂O₃ are considerably lower than in initial ZnO, which leads to a decrease of reactivity of the doped catalysts in chlorination.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1196–1199, July, 1993.     

The effect of platinum on the SnO<Subscript>2</Subscript> sorption properties

Chemisorption of SO₂ and O₂ at Pt-modified SnO₂ is studied by using the vacuum static method, with simultaneous recording of electrical conductivity, over the 22 to 300°C temperature range. The SnO₂ surface modification results in the increasing of SO₂ adsorption and weakening of the gas-surface bonding. The chemisorption enhances the samples’ electrical conductivity. The surface pretreatment with oxygen leads to the decreasing of the successive SO₂ chemisorption.     

Liquid crystal alignment properties on surface-reformed solution-derived lanthanum-doped zinc oxide films

Liquid crystal (LC) alignment characteristics were investigated using a solution-derived lanthanum-doped zinc oxide (La:ZnO) film that was exposed to various intensities of ion-beam (IB) irradiation. At an IB intensity of 1700 eV, uniform and homogeneous LC alignment was achieved, as revealed by cross-polarized optical microscopy and pre-tilt angle measurement. Field-emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) were used to verify that the IB irradiation induced physical and chemical surface reformation of the La:ZnO film that relate to LC alignment. FE-SEM and AFM revealed that the IB irradiation reformed the existing surface structure into a new structure with an altered surface roughness. The XPS results showed that the van der Waals force with anchoring energy increased as the IB intensity increased, and this profoundly affected the state of LC alignment. The capacitance-voltage (C-V) hysteresis curve was measured as a function of IB intensity to characterize the accumulated charge as a residual DC. Nearly zero C-V hysteresis was achieved at an IB intensity of 1700 eV. Therefore, a solution-derived La:ZnO film with an IB intensity of 1700 eV has great potential for high-quality LC applications.     

Chemisorption of SO2 and Cl2 on indium oxide

The mutual influence of SO₂ and Cl₂ during their consecutive chemisorption on the In₂O₃ surface has been investigated. It was found that SO₂ is chemisorbed in the uncharged form, and the amount of chemisorption decreases as the temperature increases. The preliminary chemisorption of Cl₂ results in a dramatic decrease in the amount of SO₂ sorbed and in a change in the character of the bonding of SO₂ with the oxide surface. When SO₂ is sorbed first, the temperature of the formation of chlorides during subsequent chemisorption of Cl₂ decreases.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1718–1721, October, 1994.     

Preparation and properties of solution-processed zinc tin oxide films from a new organic precursor

Transparent,smooth and dense zinc tin oxide (ZTO) thin films have been successfully produced by using a new precursor solution,zinc acetate and tin(II) 2-ethylhexanoate mixed with 2-ethanolamine in methoxyethanol.The ZTO films have been prepared by spin-coating,followed by thermal treatment in oxygen atmosphere.The morphology,composition,crystallinity and band gap energy (Eg) of the ZTO thin films have been characterized by Atomic Force Microscopy (AFM),Atomic Emission Spectrometry (AES),X-ray Diffraction (...     

Aminophenolates of aluminium,gallium and zinc: Synthesis,characterization and polymerization activity

Complexes containing aminophenolate ligands are considered as very efficient initiators of ring‐opening polymerization (ROP). Our systematic studies of the reactions of two selected aminophenols, 2‐[(p ‐tolylamino)methyl]‐4‐(2,4,4‐trimethylpentan‐2‐yl)phenol (L'H₂) and 2‐cyclohexylaminomethyl‐4‐methylphenol (L″H₂), with alkyl compounds of aluminium, gallium and zinc resulted in the formation of a variety of products depending on the type of metallic centre and alkyl groups bonded to metal atoms. New trinuclear aluminium complexes (Me₅Al₃(L′)₂ ( 1 ) and Me₅Al₃(L″)₂ ( 2 )), monomeric aluminium (^t Bu₂Al(L'H) ( 3 ) and ^t Bu₂Al(L″H) ( 5 )) and gallium (^t Bu₂Ga(L'H) ( 4 ) and ^t Bu₂Ga(L″H) ( 6 )) compounds, and dinuclear gallium (Et₂Ga(L″H)·Et₃Ga ( 7 )) and zinc (^t BuZn(L″H)]₂ ( 8 )) complexes were isolated and characterized. The molecular and crystal structures of 7 and 8 were determined on the basis of an X‐ray diffraction study. Polymerization tests showed that only three complexes ( 6 – 8 ) had activity in the ROP of ε ‐caprolactone, whereas 1 – 5 were inactive in ROP.     

从氧化锌矿制备高纯超细ZnO粉体

超细ＺｎＯ具有表面效应、体积效应、久保效应以及优良的光活性、电活性、烧结活性和催化活性 ,可用来制造气体传感器、荧光体、紫外线遮蔽材料、变阻器、图像记录材料、压电材料、压敏电阻、高效催化剂、磁性材料、陶瓷材料、化妆品及医药材料。在橡胶工业、染料油墨等领域也有应用前景[1～ 5] 。目前 ,国内外对制备超细ＺｎＯ粉体的研究文章较多 ,但以氧化锌矿为原料直接研制的文章还很少。湿化学法是近二十年来超细ＺｎＯ产品应用开发的主要活跃点之一 ,直接沉淀法是制备超细ＺｎＯ的一种重要湿化学方法 ,它是在含有一种或多种粒子的可溶…     

Chemisorption of SO<Subscript>2</Subscript> on the Zn-modified In<Subscript>2</Subscript>O<Subscript>3</Subscript> surface

Chemisorption of SO₂ and O₂ on the In₂O₃ surface containing a zinc additive (0.4–2.7 at.%) was studied in a temperature range of 22–200 °C. At least three forms of sorbed SO₂ exist on the modified In₂O₃ surface. The temperature affects the contribution of single forms of SO₂ sorption and, hence, the change in the electric conductivity. The preliminary sorption of O₂ favors the formation of a donor form of chemisorbed SO₂. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2228–2232, October, 2005.     

Interaction of Cl<Subscript>2</Subscript> and SO<Subscript>2</Subscript> with Finely Divided In<Subscript>2</Subscript>O<Subscript>3</Subscript>

The effect of O₂, Cl₂, and SO₂ on electrophysical and sorption properties of powdered In₂O₃ with a large specific area is studied at 23–200°C. The specimen is most sensitive to Cl₂ and SO₂ at near-room temperatures.__________Translated from Elektrokhimiya, Vol. 41, No. 5, 2005, pp. 529–536.Original Russian Text Copyright © 2005 by Vinokurova, Derlyukova.     

Optical properties of zinc oxide nanoparticles and nanorods synthesized using an organometallic method.

The emission properties of nanocrystalline ZnO particles prepared following an organometallic synthetic method are investigated. Spherical particles and nanorods are studied. The shape of the particles and the ligands used are shown to influence the luminescence properties in the visible domain. Two different emissions are observed at 440 nm (approximately 2.82 eV) and at 580 nm (approximately 2.14 eV) that are associated with the presence of surface defects on the particles. The first emission corresponds to the well-known yellow emission located at 580 nm (approximately 2.14 eV) with a lifetime of 1850 ns for 4.0 nm size ZnO nanoparticles. The second emission at 440 nm (approximately 2.82 eV) is observed when amine functions are present. This strong blue emission is associated with an excitation energy less than that associated with the yellow emission displaying a lifetime of nine nanoseconds. A possible hole trapping effect by the amine groups on the surface of the ZnO particles is discussed as the origin of this emission. The modification of the intensities between the two visible emissions for different particle shapes is proposed to be related to a specific location of the amine ligands on the surface of the particles.     

Antibacterial study of Eucalyptus grandis fabricated zinc oxide and magnesium doped zinc oxide nanoparticles and its characterization

Mg-doped zinc oxide and zinc oxide nanoparticles were prepared by using methanolic seed extract from the Eucalyptus grandis plant via a green approach. Phytoconstituents present in seed extract act as capping and stabilizing agents for the biosynthesis of nanoparticles. Doping of Mg to zinc oxide nanoparticles increases the bandgap energy, thus enhancing its chemical, physical and optical properties. Further, it was characterized by various techniques such as scanning electron microscopy giving morphological information about the wurtzite hexagonal structure of bio-synthesized nanoparticles. X-ray diffraction technique tells about the crystalline nature of particles and the average crystallite size for zinc oxide and doped zinc oxide nanoparticles. Mg as a dopant enhances the properties of nanoparticles, thus making it more efficiently applicable as an antibacterial agent against Escherichia coli, gram-negative bacteria.     

Nanostructural properties of zinc oxide thin films grown on non‐planar substrates

The crystallographic structure of zinc oxide thin films grown on optical fibres using single source chemical vapour deposition (SSCVD) was analysed using near edge X‐ray absorption fine structure (NEXAFS). Zinc diethyl carbamate was used as a precursor for the growth of highly conformal films in a one‐step deposition process without substrate rotation and at substrate temperatures of 400–575 °C. It was found that the growth temperatures greatly affected the crystallographic structure of the film with no preferred crystallographic orientation and negligible crystallinity at low temperatures and very high crystallinity with pure c‐axis orientation at high temperatures. Cross‐sectional analysis of the films by scanning electron microscopy (SEM) showed the presence of a film at all points around the fibre. These films generally consisted of densely packed columns that bore a strong resemblance to c‐axis‐oriented films grown on planar substrates. Copyright © 2005 John Wiley & Sons, Ltd.     

Copolymerization of propylene oxide with carbon dioxide catalyzed by zinc adipate

Copolymerization of carbon dioxide with propylene oxide in the presence of zinc adipate was studied. The effects of the temperature, nature of the solvent, and catalyst concentration on the molecular weight, molecular-weight distribution, and yields of the copolymer and propylene carbonate were examined. The structure of the polymer obtained was studied by ¹³N and ¹I NMR spectroscopy.     

纳米氧化锌的研究进展

本文对纳米氧化锌的制备技术进行了全面介绍并客观地指出其优缺点，概括了常用的表征方法，着重对纳米氧化锌的应用与研究前沿作了系统的阐述，并展望了纳米氧化锌的应用前景。     

An SKP and EIS investigation of amine adsorption on zinc oxide surfaces

A metal/oxide/polymer ‘interphase’ with mixed organic–inorganic nature insures the high stability and the strength of the adhesive joints in a variety of corrosive environments. To model the interaction of epoxy resin with a metal surface, the interaction of amines of different structure with oxidized zinc surfaces was studied by Scanning Kelvin Probe (SKP), FTIR microscopy in atmospheric conditions, and a.c. and d.c. electrochemical techniques in the aqueous electrolyte. It was shown that bidentate ligand‐ethylendiamine, forming stable chelate complexes reacts with zinc oxide with redeposition of the interphase. In air and water electrolyte, this ligand shifts the potential of Zn/ZnO electrode to the level of the oxide‐free zinc. The amines with low chelating property show low effect on the potential of Zn/ZnO. The SKP was used to measure the potential drop at epoxy resin/zinc interface. On this basis, SKP is proposed as a sensitive nondestructive technique to characterize in situ the interaction of the resin with the metal and the subsequent formation of the interphase in the metal–polymer joints. Copyright © 2010 John Wiley & Sons, Ltd.     

Effect of Oxalic Acid on Stabilization and Property of Sb-Doped Tin Oxide Sol

Zeta potential studies show that the ATO nanoparticle surface is positively charged in pH range from 2 to 5 without oxalic acid. The addition of oxalic acid brings a charge reversal on the surface of ATO particle in a wide pH range. The interaction of oxalic acid with surface of ATO nanoparticle was studied by FTIR and indicates that the most probable mechanism is the formation of Sn-O-C bonds via the condensation reaction between the oxalic acid and surface hydroxyl groups. TEM, X-ray diffraction and UV-Vis-Near IR spectra were used to characterize the nanocrystalline ATO sol and thin gel film.     

燃烧合成法制备纳米氧化锌

采用燃烧合成法制备氧化锌纳米粉体，DTA结果表明用柠檬酸作为燃烧剂比用尿素为燃烧剂时进行燃烧反应放出的热量少，更易制得纳米级氧化物．利用XRD和TEM表征样品，确定了生产纳米氧化锌粉体的最佳条件：硝酸锌与柠檬酸按9：1．5(物质的量比)形成前驱体，600℃进行反应．得到球形粉体粒径为16．4nm。