Synthesis,characterization and performance of nanosized Bi<Subscript>0.1</Subscript>Sn<Subscript>0.9</Subscript>O<Subscript>2</Subscript>–WPU organic–inorganic hybrid coatings

A series of organic–inorganic hybrid coatings consisting of organic waterborne polyurethane (WPU) and inorganic nanosized bismuth-doped tin dioxide were successfully synthesized by the in situ polymerization approach. Bi_0.1Sn_0.9O₂ nano-powders were prepared via a new route of sol–gel combustion hybrid method using acetylene black as the fuel. The formed nano-powders were characterized by transmission electron microscopy and X-ray diffraction (XRD). Bi_0.1Sn_0.9O₂–WPU was then fabricated with isophorone diisocyanate, 2,2-bis(hydroxymethyl) propionic acid and nano-Bi_0.1Sn_0.9O₂-poly(ε-caprolactone) (PCL) as the starting materials. Organic–inorganic hybrid coatings are always achieved with adjustable contents of Bi_0.1Sn_0.9O₂. The hybrid coatings with Bi_0.1Sn_0.9O₂ loading on the glass substrate exhibited good heat insulation efficiency. The tensile strength and breaking extensibility of nanocomposite film containing 1.0% of the nano-Bi_0.1Sn_0.9O₂ were measured as 9.35 MPa and 248%, respectively. The transmittance of visible light was above 80%. The heat insulation of glass coated with nano-Bi_0.1Sn_0.9O₂–WPU hybrid was over 60 °C in contrast to the commercial blank glass.     

Effects of Ti and Co on the Electrochemical Characteristics of MgNi-Based Alloy Electrodes

Mg-based hydrogen storage alloys MgNi, Mg0.9Ti0.1Ni and Mg0.9Ti0.1Ni0.9Co0.1 were successfully prepared by means of mechanical alloying （MA）. The structure and the electrochemical characteristics of these Mg-based materials were also studied. The results of X-ray diffraction （XRD） and scanning electron microscopy （SEM） show that the main phases of the alloys exhibit amorphous structures, and trace of Ni co-exists. The charge-discharge cycle tests indicate these alloys have good electrochemical active characteristics. And the cycle stability of Ti and Co doped alloy was better than that of MgNi alloy. After 50 cycle charge-discharge, the discharge capacity of the Mg0.9Ti0.1Ni0.9Co0.1 alloy was much better than that of MgNi and Mg0.9Ti0.1Ni alloys. The discharge capacity of Mg0.9Ti0.1Ni0.9Co0.1 was 102.8% higher than that of MgNi alloy, and 45.49% higher than that of the Mg0.9Ti0.1Ni alloy. During the process of charge-discharge cycle test, the main reason for the electrode capacity fading is the corrosion of Mg to Mg（OH）2 on the surface of alloys. The Tafel polarization test indicates Ti and Co improve the anticorrosion in an alkaline solution. The EIS results suggest that proper amount of Ti and Co doping improve the electrochemical catalytical activity on the Mg-based alloy surface significantly.     

掺杂二氧化锡的二氧化钛的光学性质及其光催化特性

二氧化钛多相催化是一种极具前途的环境污染深度净化技术。 本文以钛酸四丁酯和四氯化锡为原料,无水乙醇为溶剂,采用溶胶-凝胶法制备了掺杂二氧化锡的二氧化钛薄膜和复合氧化物粉体。通过测量薄膜的吸收光谱推算光学能隙,结果发现掺杂样品的光学能隙比纯二氧化钛样品有所变小。随着热处理温度的提高,掺杂和纯二氧化钛样品的光学能隙都略微降低。X-射线衍射分析表明,复合氧化物粉体的热处理温度对样品的晶体结构和光催化性能有重要影响。以掺杂二氧化锡5 % 摩尔比的样品与纯二氧化钛对照,500 ℃以下热处理样品以锐钛矿结构为主,600 ℃热处理样品为锐钛矿与金红石相共存,并显示了较好的光催化性能。透射电子显微镜观察显示,同样600 ℃热处理,掺杂样品要比纯二氧化钛具有更小的颗粒尺寸。在700 ℃热处理的样品中,掺杂样品只存在金红石相而纯二氧化钛样品中仍存有锐钛矿相。用阿伦尼乌斯经验关系式推测的晶粒生长的活化能,纯二氧化钛47.486 kJ.mol, 掺杂5 % 摩尔比的复合氧化物样品33.103 kJ.mol。以亚甲基蓝为降解物质,考察了掺杂量和热处理温度对样品的光催化性能。     

新型电解质材料CaZr0.1Ti0.9O3的制备与电性能研究

采用溶胶-燃烧法合成了可用于固体氧化物燃料电池(SOFC)的新型固体电解质材料CaZr_0.1Ti_0.9O₃。通过XRD、交流复阻抗等电化学方法对样品的结构、电导性能进行了表征,并考察了材料的烧结性能。结果表明,溶胶-燃烧法可以成功制备出具有良好烧结性能的CaZr_0.1Ti_0.9O₃电解质粉末,1400℃下得到的烧结体的相对密度可达到95%。电性能测试表明CaZr_0.1Ti_0.9O₃烧结体在中温范围内具有较高的氧离子电导率（σ^_800℃＝2.24×10^-3 S/cm）、低的电导活化能（0.89 eV）;样品的导电性能受烧结温度的影响,合理的控制烧结温度对于获得导电性能优良的CaZr_0.1Ti_0.9O₃电解质材料具有重要作用。     

Aerosol-Gel Deposition of Optically Active Thin Films in the System Y2Ti2O7-Er2Ti2O7

Optically active thin films in the system Y₂Ti₂O₇-Er₂Ti₂O₇ (YETO) have been deposited using the Aerosol-gel process. Depending on the heat-treatment temperature, amorphous or crystalline films could be prepared in the range 600–950°C. The study shows that dilution of erbium ions within a Y₂Ti₂O₇ (YTO) matrix allows to prevent short range distance interactions between those ions and to promote good photoluminescence properties of YETO films. These properties are discussed and compared with those of sol-gel derived silica films doped with erbium.     

Ultra‐low friction of fluorine‐doped hydrogenated carbon film with curved graphitic structure

Fluorine‐doped hydrogenated carbon film was grown by chemical vapor deposition technique using CH₄ and CF₄ as feedstock, with a pulse DC‐bias power supply. The structure of as‐deposited film was characterized by transmission electron microscopy and Raman spectra. The results suggested that the film could be considered as composite thin film with curved graphitic structures embedded in amorphous carbon matrix. The mechanical properties and friction coefficient were tested by TI 950 TriboIndenter and UMT‐2 at humidity of 30%, respectively. The results showed that the film exhibited high hardness (~11.04 GPa), good elasticity recovery(~83%) and ultra‐low coefficient of friction (~0.01). Copyright © 2013 John Wiley & Sons, Ltd.     

Effect of biphase on dielectric properties of Bi-doped lead strontium titanate thin films

Pb_0.4Sr_0.6TiO₃ (PST) thin films doped with various concentration of Bi were prepared by a sol-gel method. The phase status, surface morphology and dielectric properties of these thin films were measured by X-ray diffraction (XRD), scanning electron microscopy (SEM) and impedance analyzer, respectively. Results showed that the thin films with the maximum dielectric constant and minimum dielectric loss were obtained for x=0.15. For x<0.15, only pure PST perovskite phase were in the thin films. For 0.2<x<0.4, the PST/Bi₂Ti₂O₇ biphase were obtained. The thin films with pure Bi₂Ti₂O₇ pyrochlore phase were obtained for x=0.67. The biphase thin films had high tunability and high figure of merit (FOM). The FOM of PST/Bi₂Ti₂O₇ biphase thin film was about 6 times higher than that thin films formed with pure perovskite phase or pure pyrochlore phase.     

Synthesis of nanoporous activated iridium oxide films by anodized aluminum oxide templated atomic layer deposition

Iridium oxide (IrOx) has been widely studied due to its applications in electrochromic devices, pH sensing, and neural stimulation. Previous work has demonstrated that both Ir and IrOx films with porous morphologies prepared by sputtering exhibit significantly enhanced charge storage capacities. However, sputtering provides only limited control over film porosity. In this work, we demonstrate an alternative scheme for synthesizing nanoporous Ir and activated IrOx films (AIROFs). This scheme utilizes atomic layer deposition to deposit a thin conformal Ir film within a nanoporous anodized aluminum oxide template. The Ir film is then activated by potential cycling in 0.1 M H₂SO₄ to form a nanoporous AIROF. The morphologies and electrochemical properties of the films are characterized by scanning electron microscopy and cyclic voltammetry, respectively. The resulting nanoporous AIROFs exhibit a nanoporous morphology and enhanced cathodal charge storage capacities as large as 311 mC/cm².     

Ultrasensitive sensing of hydrazine vapor at sub-ppm level with pyrimidine-substituted perylene diimide film device

A pyrimidine-substituted perylene diimide (Pyrimidine-PDI), in which the electron-deficient N-heterocyclic pyrimidine rings were introduced into the core positions, were synthesized to produce a conductometric film device for the sensitive detection of hydrazine (NH₂NH₂) vapor at room temperature under ambient conditions. The Pyrimidine-PDI film device exhibited ultrafast response, excellent reproducibility, excellent selectivity and good long-term stability towards hydrazine vapor. The response and recovery time of the device was calculated to be very low as 0.4?s and 0.6?s for hydrazine vapor at sub-ppm level (0.1?ppm). Moreover, the effect of the film thickness, relative humidity and temperature on the sensing performance were also studied. To understand the sensing mechanism, the core-benzene group perylene diimide (Ph-PDI) was also designed as a comparison. The film devices of Pyrimidine-PDI and Ph-PDI to hydrazine vapor were investigated with UV–vis spectra and cyclic voltammetry, which indicated that the redox of PDIs played a critical role in the sensing process. The electrochemical properties also indicated that electron-deficient N-heterocyclic pyrimidine rings could effectively lower the LUMO energy level and improve the response of the device.     

Non‐enzymatic Fructose Sensor Based on Co3O4 Thin Film

In this study, we report on the selective of fructose on Co₃O₄ thin film electrode surface. A facile chemical solution deposition technique was used to fabricate Co₃O₄ thin film on fluorine doped tin oxide, FTO, glass. Electrode characterization was done using XRD, HRTEM, SEM, AFM, and EIS. The constructed sensor exhibited two distinctive linear ranges (0.021–1.74 mM; 1.74–∼15 mM) covering a wide linear range of up to ∼15 mM at an applied potential of +0.6 V vs Ag/AgCl in 0.1 M NaOH solution. The sensor demonstrated high, reproducible and repeatable (R.S.D of <5 %) sensitivity of 495 (lower concentration range) & 53 (higher concentration range) μA cm⁻² mM⁻¹. The sensor produced a low detection limit of ∼1.7 μM (S/N =3). The electrode was characterised by a fast response time of <6 s and long term stability. The repeatability and stability of the electrode resulted from the chemical stability of Co₃O₄ thin film. The sensor was highly selective towards fructose compared to the presence of other key interferences i. e. AA, AC, UA. The ease of the electrode fabrication coupled with good electrochemical activity makes Co₃O₄ thin film, a promising candidate for non‐enzymatic fructose detection.     

Electrical properties of thick film NTC thermistors based on SrFe0.9Sn0.1O3−δ

The thick film negative temperature coefficient (NTC) thermistors based on SrFe_0.9Sn_0.1O_3–δ were fabricated on alumina substrate by screen-printed technique. The fired thick films were characterized by X-ray diffraction, scanning electron microscopy and complex impedance analysis. The thick film samples showed compact and homogeneous microstructure. Depending on the thick film composition, the values of the resistivity at 25 °C, thermistor constant and activation energy are in the range of 65.5–4860 Ω cm, 2611–3558 K and 0.229–0.312 eV, respectively. Impedance spectroscopy analysis showed both grain and grain boundary resistances decrease with a rise in temperature for the composition SrFe_0.9Sn_0.1O_3–δ with the glass phases of 5 mol% BaBiO₃ and 5 mol% CuO. The conduction mechanism and relaxation behavior were also discussed.     

Enhanced dielectric properties of LSCO-buffered Ba(Sn<Subscript>0.05</Subscript>Ti<Subscript>0.95</Subscript>)O<Subscript>3</Subscript> thin film prepared by sol–gel processing

Ferroelectric Ba(Sn_0.05Ti_0.95)O₃ (BTS) thin films were deposited onto Pt/Ti/SiO₂/Si substrates by sol–gel technique with a 100 nm thick LSCO buffer layer. The influence of buffer layer on the phase and microstructure of the thin films was examined. Dielectric properties of the thin films were investigated as a function of frequency and direct current (DC) electric field. The results show that the LSCO buffer layer had a marked effect on the dielectric properties of the BTS films. The BTS thin films with LSCO buffer layer had enhanced dielectric properties.     

Preparation and properties of rare earth (Eu, Tb, Ho) and transition metal (Co) co-doped BiFeO3 thin films

Ferroelectric (Bi_0.9 RE _0.1)(Fe_0.975Co_0.025)O_3-δ (RE = Eu, Tb and Ho) thin films were prepared on Pt(111)/Ti/SiO₂/Si(100) substrates via a chemical solution deposition method. All thin films were crystallized in a distorted rhombohedral perovskite structure confirmed by using an X-ray diffraction and a Raman scattering analyses. Compared to the pure BiFeO₃ thin film, improved electrical and ferroelectric properties were observed for the co-doped thin films. Among the thin films, the lowest leakage current density of 4.28 × 10^?5 A/cm² was measured at an applied electric field of 100 kV/cm for the (Bi_0.9Ho_0.1)(Fe_0.975Co_0.025)O_3-δ thin film. This value is approximately three orders lower than that of the pure BFO thin film. Furthermore, a large remnant polarization (2P _r) of 60.2 μC/cm² and a low coercive field (2E _c ) of 561 kV/cm at 980 kV/cm were observed from the (Bi_0.9Ho_0.1)(Fe_0.975Co_0.025)O_3-δ thin film.     

Synthesis and electrochemical properties of LiNi0.9-xCo0.1SnxO2 as cathode materials for lithium secondary batteries

LiNi_0.9-x Co_0.1Sn _x O₂ (x = 0.00, 0.02, and 0.03) were synthesized via the rheological phase reaction method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical tests. The sample of LiNi_0.9-x Co_0.1Sn _x O₂ (x = 0.02) not only shows good cycle performance but also exhibits an excellent discharge capacity of 188 mAh/g in the first cycle at a current density of 100 mA/g in the voltage range of 3.0–4.3 V. The tin doping results in reducing the resistance and increasing conductivity of LiNi_0.9-x Co_0.1Sn _x O₂. This composite oxide is promising as cathode material for lithium-ion battery.     

Stabilities and electrical conductivities of electrode materials for use in H2S-containing gases

Stabilities and conductivities of sulfides and lithiated sulfides derived from La_0.9Sr_0.1Ga_0.8Cr_0.2O₃, LaCr_0.9Ti_0.1O₃, Y_0.9Ca_0.1FeO₃, and SrCo_0.8Fe_0.2O₃ are studied in a gas mixture of 96% H₂ and 4% H₂S at 900 °C using X-ray diffraction, microscopy, and impedance spectroscopy. Results indicate that the sulfide and lithiated sulfide derived from Y_0.9Ca_0.1FeO₃ exhibit not only high stability but also high electrical conductivity, implying that they are viable candidate electrode materials for H₂S polishing and for solid oxide fuel cells using H₂S-containing fuels. In contrast, the lithiated sulfides derived from La_0.9Sr_0.1Ga_0.8Cr_0.2O₃ and LaCr_0.9Ti_0.1O₃ exhibit relatively low electrical conductivity, although their chemical and thermal stability appear to be very good. On the other hand, the lithiated sulfides derived from SrCo_0.8Fe_0.2O₃ show inadequate chemical stability under the testing conditions even though the electrical conductivity appears to be good.     

Synthesis,microstructure, and electric properties of CaZr<Subscript>0.9</Subscript>Y<Subscript>0.1</Subscript>O<Subscript>3 – δ</Subscript> films obtained on porous SrTi<Subscript>0.8</Subscript>Fe<Subscript>0.2</Subscript>O<Subscript>3 – δ</Subscript> supports

Compact CaZr_0.9Y_0.1O_3–δ (CZY) film on a porous SrTi_0.8Fe_0.2O_3–δ (STF) support is obtained using the technique of deposition from solutions of inorganic salts in ethanol. According to the data of scanning electron microscopy (SEM), the film has a nanoporous granular structure with the grain size of 0.2 to 1 μm. The thickness of the CZY film on the STF support is about 3 μm after 15-fold solution application. The results of studying the elemental composition showed that elements of the support diffuse into the film in the course of synthesis. Analysis of the data of impedance spectroscopy shows that conductivity of the CZY film is limited the grain bulk. It is assumed that the comparatively low conductivity activation energy of the film (50.3 kJ/mol) is due to diffusion of elements of the STF support that results in variation of the film composition and properties.     

Sol-gel Synthesis and Electrochemical Performance of Li4-xMgxTi5-xZrxO12 Anode Material for Lithium-ion Batteries

The anode materials Li_4?xMg_xTi_5?xZr_xO₁₂ (x=0, 0.05, 0.1) were successfully synthesized by sol‐gel method using Ti(OC₄H₉)₄, CH₃COOLi·2H₂O, MgCl₂·6H₂O and Zr(NO₃)₃·6H₂O as raw materials. The crystalline structure, morphology and electrochemical properties of the as‐prepared materials were characterized by XRD, SEM, cyclic voltammograms (CV), electrochemical impedance spectroscopy (EIS) and charge‐discharge cycling tests. The results show that the lattice parameters of the Mg‐Zr doped samples are slightly larger than that of the pure Li₄Ti₅O₁₂, and Mg‐Zr doping does not change the basic Li₄Ti₅O₁₂ structure. The rate capability of Li_4?xMg_xTi_5?xZr_xO₁₂ (x=0.05, 0.1) electrodes is significantly improved due to the expansile Li⁺ diffusion channel and reduced charge transfer resistance. In this study, Li_3.95Mg_0.05Ti_4.95Zr_0.05O₁₂ represented a relatively good rate capability and cycling stability, after 400 cycles at 10 C, the discharge capacity retained as 134.74 mAh·g^?1 with capacity retention close to 100%. The excellent rate capability and good cycling performance make Li_3.95Mg_0.05Ti_4.95Zr_0.05O₁₂ a promising anode material in lithium‐ion batteries.     

In-situ growth of V2O5 flower-like structures on ceramic tubes and their trimethylamine sensing properties

V₂O₅ flower-like structures assembled by thin nanosheets were in-situ growth on ceramic tubes by hydrothermal process. The structural characterization indicates that V₂O₅ flower-like structures is orthogonal diamond phase, which entirely covered on the surface of ceramic tubes. TMA sensing measured results revealed that the sensor based on V₂O₅ flower-like structures exhibited fast reversible and response, good selectivity to TMA and good stability at 200 °C. The good sensing performance may be ascribed to flower-like structures and directly growth sensing film on the ceramic tube without structure damage. Our works give a simple in-situ growth flower-like structures route on sensing device, which exhibits potential application for detecting trace amounts of TMA gas.     

Magnetostatic Coupling in CoFe2O4/Pb(Zr0.53Ti0.47)O3 Magnetoelectric Composite Thin Films of 2-2 Type Structure

CoFe₂O₄/Pb(Zr_0.53Ti_0.47)O₃ (CFO/PZT) magnetoelectric composite thin films of 2-2 type structure had been prepared onto Pt/Ti/SiO₂/Si substrate by a sol-gel process and spin coat-ing technique. The structure of the prepared thin film is substrate/PZT/CFO/PZT/CFO. Two CFO ferromagnetic layers are separated from each other by a thin PZT layer. The upper CFO layer is magnetostatically coupled with the lower CFO layer. Subsequent scan-ning electron microscopy (SEM) investigations show that the prepared thin films exhibit good morphologies and compact structure, and cross-sectional micrographs clearly display a multilayered nanostructure of multilayered thin films. The composite thin films exhibit both good magnetic and ferroelectric properties. The spacing between ferromagnetic layers can be varied by adjusting the thickness of intermediate PZT layer. It is found that the strength of magnetostatic coupling has a great impact on magnetoelectric properties of composite thin films, i.e., the magnetoelectric voltage coefficient of composite thin film tends to increase with the decreasing of pacing between two neighboring CFO ferromagnetic layers as a result of magnetostatic coupling effect.     

Sensing mechanism of Pd-doped SnO2 sensor for LPG detection

In the present work, studies have been made to analyze the sensitivity, response, recovery time and sensing mechanism of Pd-doped thick film SnO₂ sensor for detection of LPG. To achieve this, thick film Pd-doped (0.25 and 1% by weight in available Indium doped SnO₂ thick film paste supplied by ESL, USA) along with an undoped (Indium doped) SnO₂ sensors were fabricated on a 1″ × 1″ alumina substrate. It consists of a gas sensitive layer (doped SnO₂), a pair of electrodes underneath the gas sensing layer serving as a contact pad for sensor. Also, a heater element on the backside of the substrate was printed for generating appropriate operating temperature at the substrate necessary for acquiring gas sensing properties. The sensor doped with 1% palladium showed the maximum sensitivity of 72% at 350 °C for 0.5% concentration of LPG. Possible detailed sensing mechanism of Pd-doped SnO₂ sensor for LPG detection has been proposed.