Study of Co-Mn-O- and Li-Co-Mn-O-Containing Layers Synthesized by Successive Ionic Layer Deposition on Silica Surface

The possibility for preparing Co₃MnO_x·nH₂O and LiCo₃MnO_x·nH₂O nanolayers by successive ionic layer deposition was examined. The resulting layers were studied by X-ray photoelectron spectroscopy, UV-Vis diffuse reflection spectroscopy, Fourier transmission IR spectroscopy, atomic absorption spectroscopy, ellipsometry, and X-ray powder diffraction.     

Damping of the Growth of Titanium Oxide Nanolayer Formed by Molecular Layer Deposition Technique on Oxidized Silicon Surface

Ellipsometric data on titanium oxide nanolayers synthesized by molecular layer deposition technique on oxidized Si(100) surface are discussed.     

分子轨道成分的计算

量子化学文献中经常涉及到“分子轨道成分”概念, 然而相应的计算方法却没有普遍得到重视, 甚至存在严重误区. 专门对分子轨道中基函数的成分、原子轨道的成分以及原子的成分这些基本概念和计算方法进行了详细讨论, 通过实例分析比较了不同方法间的差异, 同时指出了计算和分析时需要注意的问题, 给出了在方法选择上的建议.     

Synthesis of Ag7SbS6 Nanolayers on the Silica Surface by Ionic Layer Deposition

Nanolayers of Ag7SbS6 were prepared for the first time by ionic layer deposition. The influence of reactant solution concentrations and number of ionic layer deposition cycles on the layer growth kinetics was examined, and conditions were determined under which the layer formation occurs on the support surface by the reaction between ions sorbed from the reactant solutions, occurring in the layer. The layers were studied by transmission and diffuse reflection spectroscopy, X-ray spectral microanalysis, X-ray photoelectron spectroscopy, and powder X-ray diffraction.     

Atomic and Molecular Layer Deposition as Surface Engineering Techniques for Emerging Alkali Metal Rechargeable Batteries

Alkali metals (lithium, sodium, and potassium) are promising as anodes in emerging rechargeable batteries, ascribed to their high capacity or abundance. Two commonly experienced issues, however, have hindered them from commercialization: the dendritic growth of alkali metals during plating and the formation of solid electrolyte interphase due to contact with liquid electrolytes. Many technical strategies have been developed for addressing these two issues in the past decades. Among them, atomic and molecular layer deposition (ALD and MLD) have been drawing more and more efforts, owing to a series of their unique capabilities. ALD and MLD enable a variety of inorganic, organic, and even inorganic-organic hybrid materials, featuring accurate nanoscale controllability, low process temperature, and extremely uniform and conformal coverage. Consequently, ALD and MLD have paved a novel route for tackling the issues of alkali metal anodes. In this review, we have made a thorough survey on surface coatings via ALD and MLD, and comparatively analyzed their effects on improving the safety and stability of alkali metal anodes. We expect that this article will help boost more efforts in exploring advanced surface coatings via ALD and MLD to successfully mitigate the issues of alkali metal anodes.     

Deposition of Silver Nanostructures on Polymer Films by Glow Discharge

Plasma Chemistry and Plasma Processing - An atmospheric pressure glow discharge generated between the solid cathode and liquid anode was applied to produce silver nanoparticles and deposition of...     

ICP-AES法测定铋系超导材料中合金组分含量

提出了用电感耦合等离子体发射光谱仪(ICP-AES)测定铋系超导材料合金元素的含量。通过试验确定试样溶样方法,最终采用硝酸 盐酸溶解样品;选择Bi223.061 (151);Pb216.999(155);Sr346.446(97);Ca315.887(106);Cu224.700(149)作为元素分析谱线;确定最佳的仪器工作参数。应用此方法进行回收试验,回收率99%～102% ,RSD小于1.0%,。     

Molecular Layer Deposition of Silicon Nitride with Glow Discharge Activation

Russian Journal of Physical Chemistry A - The formation of silicon-nitrogen nanolayers obtained by molecular layer deposition on the GaAs surface with (100) and (110) orientations in the...     

Reversible Layer‐by‐Layer Deposition on Solid Substrates Inspired by Mussel Byssus Cuticle

The protective coating on mussel (Mytilus galloprovincialis) byssus has attracted considerable research interest because of its excellent mechanical properties such as hardness and extensibility. These special properties are known to be highly related with specific interactions between mussel foot protein‐1 and metal ions. In particular, the complexation between catechols in mfp‐1 and iron(III) has been identified as a key interaction. This finding has given opportunities for pursuing promising applications. Herein, we report that emulating the properties of the mussel byssus cuticle provides an important platform for developing reversible layer‐by‐layer (LbL) deposition, an advanced technique for surface modification. LbL films were constructed on solid substrates by sequential immersion of substrates into solutions containing iron(III) and catecholic compounds. The thickness of the LbL films was effectively controlled by increasing the immersion steps, and the reversibility of the LbL deposition was demonstrated by addition of a chelating agent.     

Resolving the Heat Generated from ZrO2 Atomic Layer Deposition Surface Reactions

In situ pyroelectric calorimetry and spectroscopic ellipsometry were used to investigate surface reactions in atomic layer deposition (ALD) of zirconium oxide (ZrO₂). Calibrated and time-resolved in situ ALD calorimetry provides new insights into the thermodynamics and kinetics of saturating surface reactions for tetrakis(dimethylamino)zirconium(IV) (TDMAZr) and water. The net ALD reaction heat ranged from 0.197 mJ cm⁻² at 76 °C to 0.155 mJ cm⁻² at 158 °C, corresponding to an average of 4.0 eV/Zr at all temperatures. A temperature dependence for reaction kinetics was not resolved over the range investigated. The temperature dependence of net reaction heat and distribution among metalorganic and oxygen source exposure is attributed to factors including growth rate, equilibrium surface hydroxylation, and the extent of the reaction. ZrO₂-forming surface reactions were investigated computationally using DFT methods to better understand the influence of surface hydration on reaction thermodynamics.     

化学气相沉积法制备氧化锡自组装纳米结构

采用化学气相沉积法在镀有5-10 nm厚金膜的SiO2衬底上, 通过控制生长条件, 实现了二氧化锡纳米结构的自组装生长, 成功制备出了莲花状和菊花状的二氧化锡自组装纳米结构. 利用扫描电子显微镜、X射线衍射等表征分析手段对样品的表面形貌、结构及成份进行表征和研究. 并在此基础上, 讨论了两种自组装纳米结构的生长机制.     

Micro-extraction of Xenobiotics and Biomolecules from Different Matrices on Nanostructures

Sample preparation is the backbone of any analytical procedure; it involves extraction and pre-concentration of the desired analytes; often at trace levels. The present article describes the applications of nanomaterials (carbon-based inorganic and polymeric materials) in miniaturized extraction such as solid phase micro-extraction, stir-bar sorptive extraction, liquid phase micro-extraction, and dispersive liquid phase micro-extraction in the analyses of aqueous samples. The nanoparticles used for micro-extractions are discussed on the basis of their chemical natures. The synthetic route and the preparation of nanomaterials are described along with the optimization strategies for micro-extraction. A comparison between the conventional materials and nanomaterials for micro-extraction is proposed. The key roles of the nanomaterials for the micro-extraction of different analytes such as drugs, pesticides, polycyclic aromatic hydrocarbons, proteins and peptides from aqueous samples are reported. The use of nanomaterials, combined with miniaturized micro-extraction techniques, proved to be highly promising for sample preparation of various matrices with analytes at trace levels.     

Optimizing the Atomic Layer Deposition of Alumina on Perovskite Nanocrystal Films by Using O2 As a Molecular Probe

Encapsulation methods have shown to be effective in imparting improved stability to metal-halide perovskite nanocrystals (NCs). Atomic layer deposition (ALD) of metal oxides is one of the promising approaches for such encapsulation, yet better control on the process parameters are required to achieve viable lifetimes for several optoelectronic and photocatalytic applications. Herein, we optimize the ALD process of amorphous aluminum oxide (AlO_x) as an encapsulating layer for CsPbBr₃ NC thin films by using oxygen (O₂) as a molecular diffusion probe to assess the uniformity of the deposited AlO_x layer. When O₂ reaches the NC surface, it extracts the photogenerated electrons, thus quenching the PL of the CsPbBr₃ NCs. As the quality of the ALD layer improves, less quenching is expected. We compare three different ALD deposition modes. We find that the low temperature/high temperature and the exposure modes improve the quality of the alumina as a gas barrier when compared with the low temperature mode. We attribute this result to a better diffusion of the ALD precursor throughout the NC film. We propose the low temperature/high temperature as the most suitable mode for future implementation of multilayered coatings.     

Electrosurface Characteristics of Element-Oxygen Nanostructures on Solid Supports

Element (Si, Ti, Al, Sn, Fe)-oxygen nanostructures on supports of various nature (SiO₂, AlOOH) have been synthesized by molecular layering from the gas phase. The electrosurface characteristics (adsorption of potential-determining ions, electrokinetic potential, zero-charge point, isoelectric point) in solutions of 1-1 electrolytes have been determined for the objects synthesized. Conditions of molecular layering for preparing Al- and Sn-oxygen nanostructures with surface properties close to characteristics of the corresponding bulk oxides have been established.     

Synthesis of Ce4MnOx·nH2O Layers on Silica Gel Surface by Ionic Layer Deposition

The possibility of synthesizing Ce₄MnO _x · nH₂O nanolayers on silica gel surface by ionic layer deposition was examined. The layers synthesized were studied by X-ray photoelectron spectroscopy, UV-Vis diffuse reflection spectroscopy, powder X-ray diffraction.     

Porous Molybdenum Carbide Nanostructures Synthesized on Carbon Cloth by CVD for Efficient Hydrogen Production

Molybdenum carbide (Mo₂C) is a promising noble-metal-free electrocatalyst for the hydrogen evolution reaction (HER), due to its structural and electronic merits, such as high conductivity, metallic band states and wide pH applicability. Here, a simple CVD process was developed for synthesis of a Mo₂C on carbon cloth (Mo₂C@CC) electrode with carbon cloth as carbon source and MoO₃ as the Mo precursor. XRD, Raman, XPS and SEM results of Mo₂C@CC with different amounts of MoO₃ and growth temperatures suggested a two-step synthetic mechanism, and porous Mo₂C nanostructures were obtained on carbon cloth with 50 mg MoO₃ at 850 °C (Mo₂C-850(50)). With the merits of unique porous nanostructures, a low overpotential of 72 mV at current density of 10 mA cm⁻² and a small Tafel slope of 52.8 mV dec⁻¹ was achieved for Mo₂C-850(50) in 1.0 m KOH. The dual role of carbon cloth as electrode and carbon source resulted into intimate adhesion of Mo₂C on carbon cloth, offering fast electron transfer at the interface. Cyclic voltammetry measurements for 5000 cycles revealed that Mo₂C@CC had excellent electrochemical stability. This work provides a novel strategy for synthesizing Mo₂C and other efficient carbide electrocatalysts for HER and other applications, such as supercapacitors and lithium-ion batteries.     

Determination of the Stoichiometric Composition of High-Temperature Superconductors by ICP-OES for Production Control

 A procedure to dissolve and analyse different types of high-temperature superconducting materials in order to determine their stoichiometric com- position is described. As sample materials Y-Ba-Cu-O and (Pb)Bi-Sr-Ca-Cu-O were analysed. They were dissolved with hydrochloric acid and analysed by simultaneous ICP-OES, which fits best for this analytical task because of its multielement capacity, its high precision of determination and accuracy. Each of the relevant metals (Pb, Bi, Sr, Ca, Y, Ba, Cu) could be determined successfully. The precision of the determination was found to be better than 2% relative standard deviation and usually even below 1%. The sample preparation and determination procedure described allows a high sample throughput, which is essential for production control. Also precursors of the superconducting materials (e.g. nitrate solutions) could be analysed by the procedure described.     

化合物分子表面积计算方法的研究

化合物的分子表面积是重要的物理化学性质参数．根据不同的应用领域及数学方法,提出了多种分子表面积算法[1-10],由此产生了“分子表面积法”,各方法的有效性在各具体应用领域都已被验证．本文将统计方法中的随机变量引入计算化合物分子表面积体系,由分子模型化技术得到化合物分子的原子坐标,不考虑化合物分子中原子的相互作用及分子间近似,直接计算分子表面积．使用该方法可以计算“净”分子表面积、“溶剂可及表面积”、甚至分子结构片段,分子结构中有交叉重叠片段及存在“空洞”的各种分子表面积,该算法及程序较简捷,适应范围广,计算结果较为满意．     

Structure Analysis of Beta-alumina Synthesized by Solid State Reaction

The crystal structure of a solid electrolyte, beta-Al2O3, was investigated by XRD analysis and demonstrated by Diamond software. Its chemical formula was verified by the Ag ion molten salt exchange method and X-ray fluorescence analysis(XRF). The chemical formula of β-Al2O3 is Na2O·8.52Al2O3, and its crystal is of hexagonal, space group P63/mmc, with a = 5.5941  and c = 22.5300 . The chemical formula of β'-Al2 O is Na2O·6.03Al2O3, and its crystal is of trigonal, space group R 3 m, with a = 5.6017 and c = 33.6219 . The maximum span in the sodion migration of β'-phase(2.4283 ) is only about a third of that for the β'-phase(6.9037 ), so the β'-phase has higher ionic conductivity than the β-phase.     

Synthesis of Aluminum Oxide Nanostructures on the Silicon Surface

Data on the synthesis of aluminum oxide nanostructures on the silicon surface by the oxidation of atomic aluminum layers with a high-frequency inductively coupled oxygen discharge plasma are reported. The conditions for the formation and the properties of aluminum oxide nanolayers were determined. It was found that this method affords oxide films with uniform structure and composition.__________Translated from Khimiya Vysokikh Energii, Vol. 39, No. 5, 2005, pp. 379–381.Original Russian Text Copyright © 2005 by Potapov, Matyuk, Trakhtenberg.