Solid Oxide Fuel Cells (SOFCs) is one of the most attractive energy conversion devices because of their high efficiency, low pollution, and fuel flexibility. La_0.2Sr_0.8TiO₃ (LST) anode material shows its potential utilization in direct oxidation of methane fuel without carbon formation. In this paper, LST powders were synthesized by traditional solid-state method, and then mixed with scandia-stabilized zirconia (SSZ) in mass ratio of 5: 5 to prepare the composite anode materials. Symmetrical cells with LST-SSZ composite anode were fabricated and measured. Their polarization resistances in hydrogen at 700℃, 750℃ and 800℃ were 5.3, 3.0 and 2.0 ?·cm², respectively. Considering the insufficient conductivity of LST, 10wt%Ni was impregnated into the composite anode to improve the anode performance. The polarization resistance of the symmetrical cell with 10wt% Ni impregnation load is obviously reduced. The maximum power density of a cathode supported single cell with 10wt%Ni-LST-SSZ composite anode are 225 mW/cm² and 175 mW/cm² in hydrogen and in methane at 750℃, respectively, and the single cell shows its stability running in methane fuels.

Corrugated SnO₂ was prepared by an effective template using cotton fibers which were sacrificed during preparation. The as-prepared SnO₂ samples were characterized by XRD, SEM, TEM, CV, galvanostatical method and EIS. The results show that the corrugated SnO₂ is composed of nanopaticles with size of 16-21 nm. The as-obtained corrugated SnO₂ electrodes can deliver a discharge capacity of 614 mAh/g at current density of 70 mA/g after 50 cycles. Even at the current density of 3 A/g the products can still deliver a high reversible discharge capacity of 405 mAh/g. As lithium storage materials, the corrugated SnO₂ shows stable cyclability and good rate capability.

Sheet-like structured zinc molybdate (ZnMoO₄) was firstly synthesized by hydrothermal method. Then, graphite (G) and conductive carbon (Cc) modified ZnMoO₄ (denoted as ZnMoO₄-G and ZnMoO₄-Cc) were fabricated by dispersing ZnMoO₄ into graphite (G) and conductive carbon (Cc) solutions, respectively. The obtained ZnMoO₄-G and ZnMoO₄-Cc composites were used as electrocatalysts for dye-sensitized solar cells (DSCs), exhibiting promising potential as counter electrode materials. The experimental results demonstrated that the DSC assembled with sole ZnMoO₄ showed an overall light conversion efficiency of 4.19%, while the DSCs made of ZnMoO₄-G and ZnMoO₄-Cc counter electrodes displayed power conversion efficiencies of 6.56% and 7.36%, respectively. The solar cell performance obtained by ZnMoO₄-Cc counter electrode was comparable to Pt-based DSCs (7.81%). Various characterization techniques, such as electrochemical impedance spectra (EIS), cyclic voltammetry (CV) and Tafel polarization curve, were employed to evaluate the electrocatalytic activity of all investigated materials. Among all investigated counter electrodes, the high solar cell performance obtained by ZnMoO₄-Cc counter electrode could be attributed to superior electrical conductivity of conductive carbon material and excellent electrocatalytic activity of sheet-like structured ZnMoO₄-Cc.

A hydrothermal method combined with a subsequent spark plasma sintering technique was successfully utilized to synthesize selenium (Se) doped bismuth telluride (Bi₂Te_3-xSe_x) (0≤x≤0.45). The influence of Se-doping on the composition and morphology of n-type Bi₂Te_3-xSe_x was studied by X-ray diffraction, scanning electron microscope and transmission electron microscope. Thermoelectric properties of the as-prepared bulk Bi₂Te_3-xSe_x nanocomposites were investigated in detail. Results showed that the grain became finer by the Se-doping. With increasing Se doping content, the electrical conductivity of bulk Bi₂Te_3-xSe_x increased firstly and then decreased. Se-doping effectively reduced the thermal conductivity and improved the Seebeck coefficient to some extent. Consequently, a maximum ZT value of 0.57 was obtained from bulk Bi₂Te_2.7Se_0.3 at 475 K, which was increased by 159% as compared with pure bulk Bi₂Te₃.

The dense Bi_1.4Sc_0.1ZnNb_1.5-xRu_xO₇ ceramics were prepared by traditional solid state reaction. The effect of Sc³⁺ and Ru⁴⁺ co-substitution on the phase structure, crystal chemistry and dielectric properties of Bi₂O₃-ZnO- Nb₂O₅ were investigated. The results reveal that all doped samples show a pure α-BZN phase structure. When x=0.055 mol, the intensity of X-ray diffraction becomes weak and diffraction peaks broaden. With the increase of x, the lattice constant a and the average distance R_(A-O') of the ceramics decrease. The bond valance calculation show that the AV(O')[A₄] and oxygen ξ parameter of 48f(O) increase, but the AV(O)[A₂B₂] gradually decreases with the amount of Ru⁴⁺ increasing. Meanwhile, the dielectric constant of samples decreases and the dielectric loss increases. The dielectric relaxation characteristics are weakened at room temperature while the relaxation behavior at low temperature is obvious. With increasing dopant, T_m shifts toward higher temperature. The ε_r-T curves of samples are fitted by the modified Curie-Weiss’s (C-W) formula. The calculations show that the degree of dielectric relaxation (γ) decreases from 1.57 to 1.33 when the Ru⁴⁺ content increases from 0 to 0.04 mol.

High pure Bismuth ferrite (BiFeO₃) powders were prepared by a solid state reaction-molten salt synthesis method (SSR-MSS method) using shock heating and chilling non-equilibrium process (SHCN process). The structure, morphology and electromagnetic properties were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscope (FTIR), Thermogravimetry-Differential Scanning Calorimetry (TG-DSC) and Vibrating Sample Magnetometer (VSM). The results indicated that SHCN process was better to get higher purity of BiFeO₃ powders than conventional equilibrium process (C process), but still has a certain number of impurity phases like Bi₂₅FeO₃₉ and/or Bi₂Fe₄O₉ as found in the products prepared by either SSR-SHCN process or MSS-SHCN process. In contrast, single-phase BiFeO₃ powders could be obtained by SSR-MSS-SHCN process. The micro-nanoscale BiFeO₃ powders presented antiferromagnetism, superparamagnetism, and/or weak ferromagnetism behavior at room temperature, but not spin-glass state at low temperature (5 K).

The difficulties of synthesis of pure Aurivillius phases largely impede them from extensive application. In this work, the first principles thermodynamics approach was applied to investigate the phase competition relation of three homologous Aurivillius series CaBi₂Nb₂O₉-nNaNbO₃, Bi₄Ti₃O₁₂-nSrTiO₃ and Bi₄Ti₃O₁₂-nCaTiO₃, in order to uncover the thermodynamic mechanism of the phase stability. The competition among different phases was analyzed by the relative Gibbs energy as a function of chemical potential of perovskite unit. The analysis reveals that most phases are able to overcome others to be the most stable ones in a certain range as chemical potential increases, which can be applied to interpret the relevant experimental phenomena including the phase mixture and disordered structures. Temperature dependence of phase competition evolutions are also studied based on the configurational and vibrational entropy effect, the former effect changes the competition relations of different phases, while the latter only increases the stable range of the lower phases.

Amorphous zinc oxide thin film was prepared through Sol-Gel method using deep-ultraviolet photochemical activation instead of high temperature annealing. The XRD patterns showed that the zinc oxide film was amorphous. XPS analysis showed that the film was mainly composed of ZnO. The Al top electrodes were deposited on irradiated thin film by DC magnetron sputtering to get Al/a-ZnO/FTO structured device. The influence of deep-ultraviolet irradiation time on switching properties was investigated to understand the mechanism of deep-ultraviolet irradiation. The results illustrate that the device after sufficient irradiation (12 h) has bipolar resistive switching property. The distribution of threshold voltage is very concentrated (-3.7 V<V_set<-2.9 V, 3.4 V<V_reset<4.3 V) which meets the need of low voltage operation of the memories. Both HRS and LRS have not obviously attenuated for at least 4000 s. The resistive switching behavior of the Al/a-ZnO/FTO device can be explained by the trap-charged space-charge-limited current mechanism.

Trifluoroacetate metal organic deposition (TFA-MOD) is one of the most promising technology routes for fabrication of YBa₂Cu₃O_7-δ (YBCO) coated conductors. In this paper, high-boiling point organic solvent diethanolamine (DEA) was added to modulate and to improve the properties of precursor solution by suppression the defect in the final films. And the thickness of single coated film was increased by increased concentration of the metal ions in the precursor solution. It is revealed that an exponential relationship was found between the thickness of precursor film after low-temperature decomposition and the ion concentration, as well as the viscosity of precursor solution vs the ion concentration. Optimizing the ion concentration and dip-coating parameters, smooth and crack-free YBCO films after crystallization are achieved with the thickness more than 1.3 μm. The films show homogeneous microstructures while dispersive heterogeneous particles appear in the surface of the thick films. Critical current density (J_c) measurement shows a decrease of J_c due to the increase of the thickness of YBCO films prepared by high concentration precursor solution, while critical currents (I_c) are distinctly improved. For instance, the I_c value of YBCO film prepared by 2.5 mol/L precursor solution is 4.7 times of that by 1.0 mol/L precursor solution.

Mesoporous zeolites X and Y with FAU structure were hydrothermally synthesized using an organos-ilane surfactant (TPOAC) as mesopore-generating agent, which was added into the conventional synthesis system of the crystalline microporous aluminosilicates. X-ray diffraction, scanning electron microscope, high-resolution transmission electron microscope, N₂ adsorption-desorption isotherms and thermogravimetric analysis were used to characterize their structural and textural features. The results showed that the presence of TPOAC led to nanoscale zeolite crystals and abundant intracrystal mesopores at diameter of 5~6 nm, forming the meso-zeolites X and Y with micropores, intra- and inter-mesopores. Both mesoporous zeolite X and Y displayed not only inherent topological and microporous structure of zeolite FAU, but also different morphology from conventional zeolite FAU crystals.

Highly porous mullite ceramics were prepared by bauxite and silica fume as raw materials and corn starch as the pore-forming agent. The phase and morphology were characterized by XRD and SEM, respectively. The influence of corn starch content on apparent porosity, bulk density and flexural strength were studied. Thermal conductivity of porous mullite was measured at 473-1273 K. A new nonlinear thermal conductivity model and several models between bulk density, flexural strength and apparent porosity were established. The results indicate that, bulk density and flexural strength of porous mullite decrease with porosity increase and conform to the exponential function relationship. Thermal conductivity of porous mullite increases with the rise of temperature and the measured values are in good agreement with values calculated by nonlinear thermal conductivity model. The new model can accurately reflect the thermal conductivity correlations for temperature, porosity, radiation and mean pore size.

Using mesophase pitch as the raw material, with the rectangular-section spinnerets at different aspect ratios (length divided by width), ribbon-shaped mesophase pitch-based carbon fibers with various cross-section sizes and crystal orientations were prepared by adjusting the spinning rate. Effects of the heat-treatment temperature and aspect ratio of spinnerets on structure and properties of the ribbon-shaped carbon fibers were investigated. The results show that the aspect ratio of spinneret and the spinning rate of pitch fibers have a significant influence on the crystal orientation of carbon fibers. Within the specified spinning rate of pitch fibers, the crystal orientation of carbon fibers varies from a parallel-fold structure to a vertical-radial structure with the decrease of the aspect ratio of the spinnerets. The electrical conductivity and the mechanical property of ribbon-shaped carbon fibers significantly increase with the increase of heat-treatment temperature. With increase in spinning rate, there is no obvious change in the room-temperature axial electrical resistivity along the longitudinal direction of fiber, whereas obvious changes in the mechanical property are observed. At 30:1 of the aspect ratio of the spinneret and 75 m/min of spinning rate, the tensile strength and young’s modulus of the graphite fibers heat-treated at 2500℃ are up to 2.53 GPa and 234.77 GPa, respectively.

A one-step hydrothermal method was developed for fabrication of flower-like Bi₂WO₆-rGO composite photocatalysts with high-efficiency visible-light photocatalytic activity. Photocatalytic experimental results for the decolorization of methyl orange (MO) aqueous solution indicated that all the resulted Bi₂WO₆-rGO photocatalysts exhibited a much higher photocatalytic performance than the pure Bi₂WO₆, and the Bi₂WO₆-rGO (0.5wt%) showed the highest photocatalytic activity with a k = 5.0×10^-2 /min, a value as 1.7 times as that of the pure Bi₂WO₆. The enhanced performance can be attributed to the cooperation effect of rGO nanosheet which promoted the effective transfer of photogenerated electrons and provided large surface area for absorbing organic pollutants. This work may provide new insights into design and fabrication of high-performance graphene-based photocatalytic materials.

Low-dimensional Bi₂Se₃ nanomaterials were discovered to be new three-dimensional (3D) topological insulators (TIs) recently, which have broad application prospect in the field of microelectronic devices and sensors. Single crystalline Bi₂Se₃ nanoplates (NPs) and nanoribbons (NRs) with jumbo size were synthesized in the vacuum quartz tube via vapor transportation. The crystal structure, composition and morphology of the as-prepared Bi₂Se₃ NPs and NRs were analyzed by XRD, EDS, Raman and SEM. It is found that both of the two specimens are well-crystallized in the direction of {001} with a high purity. Bi₂Se₃ NPs have a large lateral size of 15-180 μm, while Bi₂Se₃ NRs have a large length of 860 μm and a width of about 5 μm. Besides, the probable growth mechanism is proposed based on the analysis of the SEM images of Bi₂Se₃ NPs and NRs prepared at different temperatures and the binding energy difference along different directions. Bi₂Se₃ has a quicker growth speed along <001> and directions in relatively high temperature to form single crystalline NPs with large lateral size, while it grows faster along direction in lower temperature to get single crystalline NRs with large length. All these results not only improve the preparation process of Bi₂Se₃ nanomaterials with jumbo size, but also promote the commercial use in the field of microelectronic devices.

BiPO₄ nanorod composite photocatalyst with controllable morphology was synthesized by using Bi₂S₃ nanorods as a template. This composite catalyst exhibited excellent photocatalytic performance for methylene blue (MB) degradation under visible light irradiation. UV-Vis diffuse reflectance spectroscopy results showed that the Bi₂O₃ modified BiPO₄ catalyst had higher visible light absorption. X-ray diffraction and transmission electron microscopy results indicated that as-prepared BiPO₄ catalyst was nanorods with diameter of about 30 nm and length of 200-500 nm. Surface modification with small amount Bi₂O₃ could significantly promote visible light degradation efficiency of MB, which was about 1.7 times higher than that of the unmodified BiPO₄ catalyst. Photocurrent and N₂ adsorption experiments showed that the photocurrent and BET specific surface area increased significantly after surface modification. Bi₂O₃ modification not only enhanced visible light absorption ability of catalyst but also presented a center for the enhancement of electron transfer. The results showed BiPO₄ catalyst with Bi₂O₃ modification was a high activity photocatalytic material.

The (Ce_0.01Eu_xLu_0.99-x)₃Al₅O₁₂ (x=0.2%, 0.5%, 1%, 2%) scintillating polycrystalline powders were prepared by high temperature solid state reaction method, and the sample structure and luminescence property, especially energy transfer between Ce³⁺ and Eu³⁺, were studied. A pure cubic phase was confirmed in all samples by X-ray diffraction (XRD). X-ray excited luminescence (XEL), photoluminescence excitation and emission spectra (PL) were employed to study the influence of increasing Eu³⁺ concentration on the luminescent property of Ce³⁺ and Eu³⁺ as well as the energy transfer from Ce³⁺ to Eu³⁺. The variation of the integral intensity of luminescence of Ce³⁺ in XEL with increasing Eu³⁺ concentration illustrated energy transfer from Ce³⁺ to Eu³⁺. The luminescence behavior of Ce³⁺ and Eu³⁺ in the host of Lu₃Al₅O₁₂ under UV-visible light was studied by PL, and emission peak of Eu³⁺ under 340 nm excitation of Ce³⁺ directly indicated the energy transfer from Ce³⁺ to Eu³⁺. In addition, thermoluminescence spectra (TL) were utilized to identify the energy transfer from Ce³⁺ to Eu³⁺, and also the shifting of the thermoluminescence peaks with Eu³⁺ concentration increasing, was explained by two paths of the electrons transfering from Ce³⁺ to Eu³⁺ under thermal excitation.

GeSb_xSe_7-x (x = 0.4, 0.8, 1.2, 1.6, 2.0) chalcogenide glasses were prepared by the melt-quenching technique, and the effect of Sb on glass structures and physical properties were systematically investigated. Raman spectra of these glasses show that the glass structure gradually changes from Se chains or Se rings dominated to SbSe_3/2 pyramids and GeSe_4/2 tetrahedra cross-linked, and the degree of cross-linkage of glass network improves with Sb content increase. Meanwhile, the glass transition temperature, density, elastic moduli, and refractive index increase with Sb content increase. The transmittance spectra indicate that replacement of Se with Sb leads to gradually reducing the optical bandgap.

CuInSe₂ (CIS) and Cu_0.9In_0.9Zn_0.2Se₂ (CIZS) thin films were deposited by Radio-Frequency (RF) magnetron sputtering process. X-ray diffraction (XRD) results indicate CIZS film deposited at 300℃ (CIZS-300) is (220) preferred orientation which is different from (112) preferred orientation of other films. Cu-poor and appropriate temperature are major factors for (220) preferred orientation of grains. The Raman spectra show a strong peak around 171 cm^-1 and a weak peak around 206 cm^-1, which corresponding to A₁ and B₂ modes. Substitution of Zn for Cu leads to a broadening and blue-shift of A₁ Raman mode. The band gap E_opt of CIZS film increases due to a reduced Se p-Cu d interband repulsion with Zn doping. Scanning electron microscope (SEM) measurement demonstrates that the surface morphology of CIZS is more compact and smoother than that of CIS thin films.

Thin ceramic sheet of CaCu₃Ti₄O₁₂ has a great significance for preparation of multiplayer ceramic chip capacitors. In this work, a simple plan was made to achieve CaCu₃Ti₄O₁₂ thin ceramic sheets with excellent dielectric properties. Thin ceramic sheets of CaCu₃Ti₄O₁₂ were prepared via water-based tape casting at various sintering temperatures. The CaCu₃Ti₄O₁₂ samples sintered at 1080℃ exhibit a great performance on dielectric properties with high permittivity (ε_r=98605) and low dielectric loss (tanδ=0.028) which are better than those of samples prepared by conventional dry pressing. Meanwhile, the complex impedance spectra were measured to explain the mechanism of special electrical behaviors of CaCu₃Ti₄O₁₂ ceramics. These testing results indicate that the CaCu₃Ti₄O₁₂ ceramics via tape casting exhibits a better performance of giant permittivity and lower dielectric loss than other reports, which provides a possibility for the application of the CaCu₃Ti₄O₁₂ in modern micro-electronics technology.