Al-Ga doped nanostructured carbon as a novel material for hydrogen production in water

Production of hydrogen using Al-Ga doped nanostructured carbon in pure water is studied. The XRD and BET techniques were used for sample analyses. Dehydrogenation data of aluminum on the ordered mesoporous carbon were collected at 353 K. In the present work the oxidation rate of activated aluminum and water is investigated depending on eutectic composition and reaction temperature. The H₂ generation rate increases with the rise of temperature. Incorporated Al-Ga-OMC nanocomposite had faster (hydrogen production rate was 112 ml H₂ min⁻¹ g⁻¹) and more efficient (hydrogen production yield was 100%) dehydrogenation kinetics than incorporated Al-OMC nanocomposite and ball-miled active aluminum.     

铂族金属载体催化剂薄膜材料的研究与发展

铂族金属栽体催化剂薄膜材料由于高效催化性及特殊的选择性而获得广泛应用。作者评述了其在氢能源和燃料电池技术领域的研究现状；其开发中计算机模拟与控制的辅助设计；其不同制备技术的特性及连续生产装置的探讨；其物理结构、成分和催化性能指标的分析手段的发展。并指出其今后发展的重点仍然是设计开发生产具有高催化性、高选择性、低铂族金属含量的二维材料。     

Synthesis of biomorphic hierarchical CeO2 microtube with enhanced catalytic activity

A biomorphic CeO₂ microtube with multiple-pore structure was fabricated by using the cotton as biotemplate, through cerium nitrate solution infiltration and thermal decomposition. Field emission scanning electron microscope (FESEM), powder X-ray diffraction (XRD), transmission electron microscope (TEM), N₂ adsorption–desorption isotherms, temperature-programmed reduction (TPR) and CO oxidation were used to characterize the samples. The results indicated that the synthesized products were composed of crystallites with grain size about 9 nm and exhibited a fibrous morphology similar to the original template and possessed a specific surface area (BET) of 62.3 m²/g. Compared with the conventional CeO₂ particles, the synthesized materials showed a superior catalytic activity for CO oxidation. For the synthesized fibrous CeO₂, the CO conversion at 320 °C was above 90% and a 100% CO conversion was obtained at 410 °C.     

Electrocatalytic Processes on PbO<Subscript>2</Subscript> Electrodes at High Anodic Potentials

The determination of the electrocatalytic activity and selectivity of electrodes with respect to the target process is considered to be of interest both in the theoretical aspect for the development of electrocatalysis theory and in application for efficient electrocatalysts which can be used in electrochemical systems for wastewater treatment. The purpose of the given work was to identify the relationship between the chemical and phase composition of materials based on lead dioxide, their physicochemical properties, and their electrocatalytic activity. The main research methods were quasi-stationary polarization and impedance spectroscopy, photocolorimetry, fluorescent and spectrophotometry in the UV and visible regions, atomic absorption spectroscopy, and high performance liquid chromatography (analysis of the solutions). It was shown that the modification of lead dioxide by ionic additives results in significant changes in the electrocatalytic activity of the system in respect to the oxygen evolution reaction and electrochemical oxidation reactions of organic compounds. It was found that, at low polarizations, the oxygen evolution reaction is limited by the electrochemical desorption step (the second electron transfer), and its overpotential at PbO₂-modified electrodes increases in the order that coincides with the dependence in which the number of oxygen-containing particles strongly bound to the electrode surface increases. It was found that the rate of oxidation of organic substances on the anode materials involved is directly proportional to the amount of oxygen-containing radicals formed on the electrode during the water oxidation.     

Hydrogen solution properties in a series of amorphous Zr–Hf–Ni alloys at elevated temperatures

Amorphous alloys are anticipated as new membrane materials for high purity hydrogen production, as substitutes for expensive palladium alloys. For amorphous Zr–Ni-based alloys reported to date, hydrogen permeability increases with Zr content. Hydrogen solution properties in a series of amorphous Zr–Hf–Ni ternary alloys were measured carefully using the Sieverts method and residual hydrogen measurements to investigate the reason. Results indicate that hydrogen solubility in the ternary alloys increases with increasing Zr to improve hydrogen permeability, not because of the geometrical atomic structure but because of higher hydrogen affinity of Zr than that of Hf. Increased permeability with Zr in other amorphous Zr–Ni-based alloys is also expected to be attributable to the same reason. Additionally, hydrogen was found with low mobility, and was not removable even after 10 h evacuation at 573 K; the importance of decreasing low mobility hydrogen as a countermeasure against hydrogen embrittlement was pointed out. Equilibrium hydrogen concentration was found not to obey Sieverts’ law with respect to hydrogen pressure. Rather, it was linear roughly to the quarter power. Parameters to reproduce pressure–composition isotherms were determined using Kirchheim's theory.     

类芬顿铁基功能材料除砷的应用与机制（英文）

亚砷酸盐(As(Ⅲ))和砷酸盐(As(V))是天然水中砷的主要存在形态,其中As(Ⅲ)由于其高毒性和高迁移率,对人类和环境的危害远大于As(V)。因此,将As(Ⅲ)预氧化为As(V)被认为是降低砷毒性、提高砷去除率的有效手段。由于铁基功能材料具有较高的催化活性和砷亲和力,在非均相类芬顿体系中可以快速将As(Ⅲ)氧化为As(V),然后通过吸附和表面共沉淀将As(V)从水中去除。本文综述零价铁和铁(羟基)氧化物等不同铁基功能材料对砷去除的影响,以进一步阐明非均相芬顿法中As(Ⅲ)的催化氧化及去除机理。最后,本文还展望了应用于As(Ⅲ)氧化的铁基功能材料目前面临的主要挑战和机遇。     

PbO2 anodes modified by cerium ions

Lead dioxide coatings deposited from methanesulfonate electrolytes that also contain Ce³⁺ ions have been investigated. It has been shown that, during the deposition, are formed lead dioxide electrodes micromodified by cerium, which have different physicochemical properties than do traditional PbO₂ anodes. The electrocatalytic activity of materials involved in respect to oxygen evolution and oxidation of p-nitroaniline has been investigated.     

Examination of the wear properties of HVOF sprayed nanostructured and conventional WC-Co cermets with different binder phase contents

There has been an increase in interest of late regarding the properties of thermally sprayed WC-Co cermets with nanograin carbide particles. These powders have shown interesting properties in sintered components, giving high values of hardness (2200–2300 VHN) and improved wear properties. The method used for the processing for these materials—solution formation, spray drying and chemical conversion, rather than introduction of WC as solid particles to a molten binder—allows the formation of sub-100 nm WC particles as a hard second phase. The work presented here examined the effect of composition on the microstructure and wear properties of some nanostructured WC-Co materials. WC-Co cermets with 8, 10, 12, and 15% Co binder phase were deposited using a Sulzer Metco hybrid DJ HVOF thermal spray system. Optimization of deposition conditions was necessary because of the unique morphology of the powders (thick-shelled hollow spheres) to produce dense consolidated deposits. There is a higher degree of decarburization of the WC phase in the nanostructured materials compared with the conventional WC-Co. This dissolution of the hard phase is also noted to increase on decreasing binder phase content. The nanostructured WC-Co coatings have a lower wear resistance compared with the conventional WC-Co for abrasive wear and small particle erosion. The abrasive wear resistance of these nanostructured materials was found to increase on decreasing cobalt binder content. This trend in abrasive wear resistance is consistent with studies on conventional sized cermets and is believed to be more dependent upon proportion of binder phase content than degree of decarburization for the materials studied. The small particle erosion resistance of the nanostructured coatings was found to increase on increasing cobalt content.     

Photocatalytic Active Titania Thin Films through Oxidation of Metallic Ti in Aqueous H2O2 Solutions Containing Various Block Copolymers

利用添加了嵌段共聚物P123、F127及硝酸的双氧水溶液直接氧化钛金属基体制备不同纳米形貌TiO2光催化薄膜。采用X射线衍射(XRD)、扫描电镜(SEM)、紫外-可见漫反射光谱(UV-VisDRS)等技术分析样品的微观结构和形貌,以光催化降解若丹明B测定薄膜的光催化性能。结果表明,Ti-H2O2反应体系中仅添加嵌段共聚物的薄膜结晶呈树枝状,加入硝酸后薄膜形成纳米花结构。450oC热处理后,薄膜为锐钛矿与金红石的混晶结构,平均晶粒尺寸在12～20nm之间。薄膜的间接禁带宽度为2.65～2.85eV,显著低于TiO2块体。添加P123获得的薄膜的光催化性能优于添加F127的薄膜。     

Ti-H2O2反应添加嵌段共聚物制备光催化活性的TiO2薄膜

利用添加了嵌段共聚物P123、F127及硝酸的双氧水溶液直接氧化钛金属基体制备不同纳米形貌TiO2光催化薄膜.采用X射线衍射(XRD)、扫描电镜(SEM)、紫外-可见漫反射光谱(UV-Vis DRS)等技术分析样品的微观结构和形貌,以光催化降解若丹明B测定薄膜的光催化性能.结果表明,Ti-H2O2反应体系中仅添加嵌段共聚物的薄膜结晶呈树枝状,加入硝酸后薄膜形成纳米花结构.450℃C热处理后,薄膜为锐钛矿与金红石的混晶结构,平均晶粒尺寸在12～20 nm之间.薄膜的间接禁带宽度为2.65～2.85 eV,显著低于TiO2块体.添加P123获得的薄膜的光催化性能优于添加F127的薄膜.     

Production and Characterization of Metastable ZrO<Subscript>2</Subscript>-Al<Subscript>2</Subscript>O<Subscript>3</Subscript>Coatings Obtained by APS + Quench

Producing nanostructured materials through metastable phases is an interesting novel route in the field of ceramic materials. Due to their small grain size and uniform structure, these nanostructured bulk materials exhibit very interesting properties. Metastable coatings can be produced starting from microstructured powders through atmospheric plasma spray technique, followed by a quenching route. The initial powders are melted during the spraying and deposited over a substrate that is quenched with liquid nitrogen feeders, producing metastable coatings. The thermal-sprayed coatings have been characterized using x-ray diffraction, scanning electron microscopy, field emission scanning electron microscopy, and energy dispersive spectroscopy. The properties of such coatings have been also studied obtaining promising results.     

热喷涂纳米涂层20年回顾与展望

概述了热喷涂纳米涂层的发展,包括通过纳米粉体的再造粒技术形成热喷涂纳米结构涂层的过程,热喷涂纳米结构氧化铝/氧化钛耐磨抗蚀涂层材料的研发、产业化与成功应用,偶然获得热喷涂纳米自润滑涂层的过程,液料热喷涂纳米热障涂层的研发,新型热喷涂纳米热障涂层材料等。展望了热喷涂纳米涂层技术在国防和民用领域的应用前景,预计到2025年,全球热喷涂纳米涂层市场会达到65亿美元,其中20%左右的市场份额在中国。最后,指出通过对纳米粉体进行再造粒,在纳微观尺度上调控可喷涂粉体喂料的成分和组织结构,能够获得各种所需性能的纳米结构热喷涂涂层,可以用纳米材料制备出常规材料无法获得的全新高性能热喷涂纳米涂层,以满足各种高端装备关键构件的各种表面性能需求。所以,要通过政产学研用合作创新,加快纳米结构可喷涂粉体喂料产业化,发展高性能的热喷涂纳米涂层。     

High-temperature electrical conductivity of Li–Ge ferrites

Electrical conductivity of germanium-substituted lithium ferrites of different compositions have been investigated as a function of composition and temperature. Plots of log(σT) versus 10³/T are almost linear and have shown a transition near the Curie temperature. The activation energy in the ferromagnetic region is in general less than that in the paramagnetic region. An attempt is made to explain the conduction mechanism in Li–Ge ferrites.     

纳米高频软磁薄膜材料研究进展

由于高频软磁薄膜材料具有巨大的应用前景因此获得了人们广泛的关注。对纳米合金软磁薄膜、纳米软磁颗粒膜、多层膜以及图形化薄膜进行了分类综述,分别介绍了各类薄膜的制备方法、化学成分、微观结构特点和高频物理性能,并对影响其性能的主要因素进行了讨论。由于纳米高频软磁薄膜材料相对于传统磁性材料具有显著优势,所以纳米合金软磁薄膜有望取代铁氧体作为制作高频磁性器件的主要应用材料。由于纳米软磁颗粒膜、多层膜以及新兴的图形化薄膜具有材料结构设计和物性剪裁的自由度,因此将是今后的重点研究方向。     

塑性变形中晶粒变形与细化机制的影响因素

讨论了层错能、应变速率和变形温度等因素在塑性变形制备超细晶/纳米晶材料的变形过程中,对变形机制与晶粒细化机制的影响.研究表明,随着层错能的降低,晶粒的变形机制会由位错滑移向机械孪生转变,有利于晶粒的细化.应变速率的增加与变形温度的降低有利于抑制位错动态回复、增加流变应力,促使晶粒进一步细化.     

等离子喷涂超高温热障涂层用纳米结构La2(Zr0.75Ce0.25)2O7球形喂料的研究

目的通过纳米粉体造粒技术制备出适合热喷涂超高温用纳米结构La2(Zr(0.75)Ce(0.25))2O7球形喂料,进而采用热喷涂方法制备出纳米结构的热障涂层,以满足下一代热障涂层服役温度需求。方法以化学共沉淀法合成的纳米La2(Zr(0.75)Ce(0.25))2O7粉末为原料,通过球磨、喷雾干燥及热处理工艺制备出纳米结构的La2(Zr(0.75)Ce(0.25))2O7喂料,进而采用大气等离子喷涂方法制备出纳米结构La2(Zr(0.75)Ce(0.25))2O7热障涂层。利用扫描电镜(SEM)和透射电镜(TEM)对原始纳米粉体、纳米喂料及喷涂态涂层进行显微形貌和组织结构分析。此外,通过电感耦合等离子体原子发射光谱法(ICP-AES)对制备的纳米喂料进行成分分析。结果制备出的纳米结构La2(Zr(0.75)Ce(0.25))2O7喂料表面光滑、呈球形,成分与化学计量比基本一致。相对于原始纳米粉末,喂料晶粒长大并不显著。喷涂态涂层部分晶粒长大,但仍保留纳米结构。结论成功制备出纳米结构La2(Zr(0.75)Ce(0.25))2O7球形喂料及纳米结构热障涂层,有望作为下一代超高温热障涂层材料。     

Electrocatalytic behaviour of NiBi coatings for hydrogen evolution reaction in alkaline medium

The nickel-bismuth binary coatings with various chemical compositions were galvanostatically deposited on the copper electrode in view of their possible applications as electrocatalytic materials for the hydrogen evolution reaction (HER) in alkaline solution. The HER activity of coatings was tested with the help of potentiodynamic measurements and electrochemical impedance spectroscopy (EIS) technique. The electrochemical characterization was achieved by the means of cyclic voltammetry (CV). The surface morphology and surface composition of coatings were determined with scanning electron microscopy (SEM), and energy dispersive X-ray (EDX). The potentiodynamic measurements show that, the binary coatings decrease the hydrogen over potential and increase the current density values for HER. The EIS analysis confirms, the charge transfer resistances decrease and the double layer capacitance values increase for binary coatings. The EDX results in sign that the composition of binary coating changes by using coating bath. The Cu/NiBi-2 coating (Ni²⁺/Bi³⁺ is 99.71:0.29 molar ratio) is the best suitable cathode composition for the HER in alkaline media under these experimental conditions.     

光/电催化剂的表面调控在苯甲醇绿色氧化中的应用

综述了近年来国内外关于高效光/电催化剂在水分解制氢耦合苯甲醇绿色氧化中的相关研究进展,重点阐述了构筑不同形貌、表面缺陷工程和掺杂改性的催化剂对促进苯甲醇氧化的作用机制,并对催化剂的合成方法、光/电化学性能、反应机制进行了详细概括。在光催化领域,介绍了抑制催化剂表面光生电子和空穴的复合、调控活化活性位点等方法。在电催化领域,介绍了催化剂活性位的筛选、导电性和本征活性提升的有效策略以及将电催化与膜分离相结合的一体化技术,并构建了双功能催化剂,实现高效、低能耗产生H2的同时,能选择性地将BA氧化。最后提出了该领域未来需要面对的挑战和机遇,从不同的角度和方面综合分析,为进一步提升水分解制氢耦合绿色合成高附加值有机化学品的光/电催化剂提供理论指导。     

New composite thermoelectric materials for energy harvesting applications

The concept of using nanostructured composite materials to enhance the dimensionless thermoelectric figure of merit ZT relative to that for their counterpart homogeneous alloyed bulk crystalline materials of similar chemical composition is presented in general terms. Specific applications are made to the Si-Ge and Bi_2-−xSb_xTe₃ systems for use in high-temperature power generation and cooling applications. The scientific advantages of the nanocomposite approach for the simultaneous increase in the power factor and decrease in the thermal conductivity are emphasized insofar as their simultaneous occurrence is enabled by the independent control of these physical properties through the special properties of their nanostructures. Also emphasized are the practical advantages of using such bulk samples both for thermoelectric property measurements and for providing a straightforward path to scaling up the materials synthesis and integration of such nanostructured materials into practical thermoelectric powergeneration and cooling modules and devices.     

超声表面滚压技术制备梯度纳米结构材料

介绍了超声表面滚压技术（USRP）在制备梯度纳米结构材料中的应用。USRP技术能在材料表面构建梯度纳米结构层并引入残余压应力,同时显著降低材料表面粗糙度并提升表面均匀性。讨论了与USRP加工工艺及过程密切相关的微观结构演变和表面特性,分析了不同材料体系及工艺参数对USRP处理的影响规律。研究表明,采用合适的USRP处理工艺可改善材料表面的力学性能,即硬度,强度,耐磨性及抗疲劳性能等,而腐蚀/氧化行为则更依赖于材料的组织结构、表面完整性、应力状态、不同的腐蚀介质及服役环境等因素的综合作用。此外,对USRP制备梯度纳米结构材料面临的一些基础科学问题和工业应用探索进行了讨论和展望。