CoFe₂O₄-(PZN-PZT) multiferroic composite ceramics were prepared by low temperature sintering using traditional ceramic method. The influences of mixed mode, PZT shell and composition on structure, magnetic and magnetoelectric coupling properties were studied. XRD and TEM results show that CoFe₂O₄/PZT core-shell nanostructured particles are prepared by the Sol-Gel method. A 10-20 nm thick PZT shell formed on the surface of CoFe₂O₄ particle. EDS analyses show that low temperature sintering and barrier layer effectively inhibit the elements diffusion of the two phases. SEM images and magnetoelectric property measurement show that PZT shell coated on CoFe₂O₄ particles and the stirring process improve the magnetic particles content in com-position, match the sintering process perfectly, and improve the magnetoelectric coupling properties effectively. The coated and stirred sample CoFe₂O₄-(PZN-PZT) with volume ratio of 4:6 which sintered at 1000℃ show maximum magnetoelectric coupling coefficient of (18.3 mV/(cm·Oe)) at 10 kHz.

Electroless plating was utilized to deposit nickel nanoparticles on the reduced graphene oxide (RGO). By adjusting the nickel salt precursor concentration, three kinds of Ni-RGO with different nickel contents were synthesized, namely Ni-RGO-1, Ni-RGO-2 and Ni-RGO-5. Transmission electron microscopy and X-ray diffraction were employed to study the surface morphology and crystal structure of as-prepared Ni-RGO. The electromagnetic performance of graphene oxide and Ni-RGO was characterized. The results indicated that the permittivity of Ni-RGO was above 8, almost three times higher than that of pristine graphene oxide. Ni-RGO-1 exhibited the best electromagnetic wave absorption performance, although the concentration of nickel precursor is the lowest one among three samples. The minimal reflection loss was up to -24.5 dB for Ni-RGO-1 with a thickness of 2 mm.

MoS₂/GF composites were synthesized by hydrothermal method using graphene oxide (GO), sodium molybdate and thiourea as raw materials with assistance of different cationic surfactants (C₁₄TAB, C₁₆TAB, C₁₈TAB). The investigation of as-prepared samples by X-ray diffraction and scanning electron microscopy demonstrate that the composites have presented different morphologies and microstructures which may be resulted from the cationic surfactants. Electrochemical performances for reversible Li⁺ storage of the composites reveal that the capacities, cycling stability and rate capability are influenced by different morphologies and microstructures. Comparison to C₁₆TAB and C₁₈TAB assistance, the composite synthesized with C₁₄TAB assistance delivers a high first discharge capacity of 955 mAh/g and reversible capacity of 751 mAh/g after 50 cycles, shoowing excellent rate capability. The improvement in the electrochemical performances of the composites synthesized with C₁₄TAB assistance is attributed to its special particle-on-sheet structure and synergistic interactions between graphene and MoS₂.

Supercapacitors have attracted dramatic attentions in recent years for their apparent advantages, such as fast charge/discharge rate, high power density and high stability. However, it is still a challenge to improve their energy density for their practical applications. One of the strategies to overcome this drawback is to broaden the working voltage of the devices through assembling asymmetric supercapacitors. Herein, Mn₃O₄@RGO nanocomposites were successfully synthesized by using one-pot approach with Mn(Ac)₂ and GO in the mixed solvent of ethanolamine and water (3:1) without adding any surfactant. The asymmetric supercapacitors (Mn₃O₄@RGO//RGO) assembled with Mn₃O₄@RGO and RGO exhibit excellent performances in energy storage. The asymmetric supercapacitors can achieve a maximum energy density of 21.7 Wh/kg at power density of 500 W/kg and a maximum power density of 8 kW/kg at energy density of 11.1 Wh/kg, based on the total mass of active materials. The Mn₃O₄@RGO//RGO supercapacitors also demonstrated excellent durability retaining 88.4% of their specific capacitances even after 5000 charge/discharge cycles. The excellent performances of Mn₃O₄@RGO//RGO devices in energy storage can be attributed to high density of Mn₃O₄ nanoparticles grown directly on the surfaces of RGO nanosheets, which can dramatically improve the conductivity of materials.

Mesoporous SnO₂ was synthesized via a hydrothermal process using tin chloride (SnCl₄·5H₂O) and urea ((NH₂)₂CO) as raw materials, with a block polyether F127(EO₁₀₆-PO₇₀-EO₁₀₆) as a template. The analysis results (XRD, TEM, BET, etc) show that the amount of F127 has significant influence on pore structure of mesoporous SnO₂. With increasing dosage of F127, specific surface area and pore volume of the mesoporous SnO₂ increase with pore size distribution relatively broad. The results of the electrochemical tests indicate that existence of mesopores not only provide the path for deinsertion and insertion of Li⁺, but also buffer the huge volume expansion of tin dioxide, which consequently improves the electrochemical performances of mesoporous SnO₂ as an anode material. When the amount of F127 is 6.0 g, the as-prepared 6F-SnO₂ with a BET specific surface area of 124 m²/g and average pore size of 4.94 nm, displays optimal cycle performance and rate performance which the reversible capacity of the 6F-SnO₂ maintains 434 mAh/g at 60 mA/g after 30 cycles. In addition, the cyclic voltammetric test reveals that the reversible reduction of partial Li₂O with high activity can provide additional reversible capacity.

ZrB₂ nanoparticles were synthesized synergistically by Sol-Gel method and carbothermal reduction reaction using zirconium n-propoxide, acetic acid, boric acid and xylitol as starting materials. In the reaction system, xylitol acted as a carbon source for the carbothermal reduction reaction and chelated boron, leading to the formation of coordination compound through its polyhydroxy reaction with boric acid. According to the Fourier Transform infrared spectra and thermal analysis of gel precursor, the effects of sol and gel reaction processes on the carbothermal reduction reaction temperature and gelation time were discussed. The results show that the polyhydroxy compound of xylitol is beneficial to initiate reactions and gelation, which makes the threshold throughout the whole chemical processes easy to overcome. The gel does not need aging treatment and the reaction temperature is lowered. Besides, a single phase of equiaxed ZrB₂ nanoparticles could be obtained from nascent state gel calcined at 1450℃ with n(xylitol)/n(zirconium n-propoxide) of 1.4. The average diameter and oxygen content of ZrB₂ nanoparticles are ca. 50 nm and 1.36wt%, respectively.

Al₂O₃ cannot be directly brazed with aluminum due to the poor wettability of aluminum on alumina below 850℃. Based upon effect of sputtered aluminum wetting on Al₂O₃, a direct brazing method was proposed to utilize sputtered Al-based films as brazing fillers on alumina. The results show that direct brazing of Al₂O₃ by Al and Al-Cu alloy can be achieved at 680℃ in vacuum with vacuum level only of 0.1 Pa. Through this method, the shear strength of joint with pure Al as brazing filler is 115 MPa and that with Al-1.6at% Cu is up to 163 MPa. When the Cu content in the Al-Cu alloy increases to 14.3at%, the shear strength of joint decreases to 127 MPa, due to the joint fracture generating at the interface caused by the interfacial segregation of Cu. Moreover, the principle of this direct brazing method not based on wettability of molten metal is analyzed.

A reactive air brazing Ag-CuO alloy was evaluated for brazing dual phase oxygen membrane Ce_0.8Gd_0.2O_2-δ- NdBaCo₂O_5+δ (CGO-NBCO). Contact angle tests were observed between Ag-Cu brazes and CGO-NBCO in air and the interfacial microstructures of the used samples were evaluated by SEM. The results indicate that the wetting angle decreases from 35° to 20° with the content of Cu increased from 6.6mol% to 15.8mol%. It is found that there are copper oxide-enriched zones formed in the junction of the alloy and substrate. The wettability between Ag-CuO alloy and oxygen membrane CGO-NBCO is improved due to the interfacial reaction between Cu oxides in braze and the surface layers of CGO-NBCO substrates to form compounds of Ba-Cu-O, Co-Cu-O and Nd-Ce-Cu-O oxides. The new formed interface reaction layers promote the wettability of the rest braze.

CeO₂/Fe₃O₄ magnetic nanoparticles were prepared for promoting the catalytic activity of Fe₃O₄, which is applied as the catalyst of heterogeneous Fenton reaction system for the degradation of ofloxacin. Several factors that affected the degradation efficiency of the system such as CeO₂ content, H₂O₂ concentration and pH were investigated. The mechanism of catalytic degradation was also explored via the measurement of iron ion and kinetics fitting. The results show that the catalytic activity of CeO₂/Fe₃O₄ is better than that of Fe₃O₄. The degradation efficiency of ofloxacin increases with the addition of CeO₂ content, H₂O₂ concentration or solution acidity increase. The degradation effect of ofloxacin is the best for CeO₂/Fe₃O₄(molar roction=0.780)-H₂O₂ catalytic system when H₂O₂ concentration is 100 mmol/L and pH is 3, which accords first order kinetics model. The catalytic ability of CeO₂/Fe₃O₄ is strengthened through surface catalytic reaction and electronic transfer of oxygen vacancies of CeO₂ during catalytic reaction.

Crack-free tubular yttria-stabilized-zirconia (YSZ) nanofiltration membranes was fabricated via an aqueous Sol-Gel process, using zirconium oxychloride as precursor and water as solvent. This procedure was completely free of organic solvent and thus was environmentally friendly. The influences of precursor concentration and calcination temperature on the particle size of sols, crystal and pore structure were investigated. The results revealed that the sol prepared with lower precursor concentration and calcined at 400℃, has higher content of monoclinic phase, thus leading to the increase of pore size. Subsequently, addition of 8mol% yttrium into the sol inhibits phase transformation from tetragonal to monoclinic and grain growth, as well as avoid membrane cracking. In addition, retention experiment result shows that the YSZ nanofiltration membrane exhibits a molecular weight cut-off (MWCO) of 860 Da and a water permeability of 200 L/(m²·h·MPa). Furthermore, ions retention properties of YSZ nanofiltration membrane towards four solutions like NaCl, Na₂SO₄, CaCl₂, and MgCl₂, were conducted at pH 6 and a transmembrane pressure of 0.8 MPa. The retention properties of YSZ nanofiltration membrane towards CaCl₂ and MgCl₂ solutions reach maximum values of 65% and 78%, respectively.

B and S co-doped TiO₂ was prepared by a typical hydrothermal synthesis. Then the obtained B-S-TiO₂ was dissolved in organic solvent to form paste and then coated on FTO conducting glass by screen printing to prepare nanofilm. The CdS/B-S-TiO₂ composite electrodes was obtained by chemical bath deposition (CBD) using B-S-TiO₂ nanofilm and CdS quantum dots (QDs). The obtained samples were characterized by EDS, XRD, TEM and UV-Vis. The results show that B and S do not change the structure of anatase TiO₂. Noticeable shifts of absorbance edge towards longer wavelength were observed and the absorbance intensity of the B-S-TiO₂ nanofilm increases significantly. Furthermore, NiS was prepared as counter electrode by CBD and a modified polysulfide redox couple, ((CH₃)₄N)₂S/((CH₃)₄N)₂S_n, was employed as electrolyte to assemble CdS quantum-dots (QDs)-sensitized solar cells. The measurements show that the cells have an enhanced energy conversion efficiency under AM 1.5 G illuminations which increased from 3.21% to 3.69%, about 14.9% increment, with a significantly high open voltage (V_oc) of 1.218 V, a high filled factor (ff) of 88.7%, and a short-circuit photocurrent (J_sc) of 3.42 mA/cm².

Spherical phosphors of (Lu_0.95Eu_0.05)₃Al₅O₁₂ ((Lu_0.95Eu_0.05)AG) with good dispersion was achieved through precursor synthesis via homogeneous precipitation method using urea as the precipitant, followed by annealing. The size of spherical particle can be effectively controlled by adjusting the urea concentration. Based on it, the synthesis, phase evolution and photoluminescent properties of the (Lu_0.95Eu_0.05)AG phosphors were tested by XRD, FE-SEM, TEM, BET, PLE/PL, and fluorescence decay analyses. The results showed that the precursors were converted into phase-pure (Lu_0.95Eu_0.05)AG garnet at a relatively low temperature of 1100℃. The (Lu_0.95Eu_0.05)AG garnets possessed high theoretical densities which were suitable for the application of scintillation material. The phosphors exhibited strong orange red emissions at 592 nm (the ⁵D₀→⁷F₁ magnetic dipole transitions of Eu³⁺) upon UV excitation into the charge transfer band (CTB) at 235 nm, with CIE chromaticity coordinates of (0.63, 0.37). The intensity of 592 nm emission increased with the particle size increase, while the lifetime of 592 nm emission decreases at a higher particle size. Thus, the spherical phosphors of (Lu_0.95Eu_0.05)AG garnet developed in the present work were expected to be a new type of phosphor which may be widely used in lighting and displaying areas.

A series of environmentally benign near-infrared reflective green nano-pigments were synthesized via Sol-Gel method with a general formula of Y₂Ba_(2-x)Cu_xO₅(x=0, 0.25, 0.50, 0.75 and 1.0). The crystal structure, morphology and optical properties of the synthesized pigments were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), UV-Vis-NIR diffuse reflectance spectra, and high accuracy spectrophotometer. Analysis results demonstrated that Cu ion was successfully introduced into the Y₂Ba₂O₅ lattice of which grain size decreased from 62.1 nm to 54.7 nm. The systematic substitution of Cu²⁺ for Ba²⁺ in Y₂Ba₂O₅ changed color from white to green (a*=-21.61) and decreased band gap from 2.30 eV to 2.04 eV. These pigment samples revealed the uniform spherical-like morphology with an average size of 150-300 nm. When Cu²⁺ was introduced, the infrared reflectance of pigment sample was decreased. However, the pigment still displayed high near infrared reflectance (68.80%) and solar reflectance (45.95%), while the doping of Cu²⁺ up to x=0.50. Therefore, such green high near-infrared reflectance from these Y₂Ba_(2-x)Cu_xO₅ powders have great potential in serving as cool pigments for building coatings.

Lutetium oxyorthosilicate (Lu₂SiO₅, LSO) films co-doped with Ce³⁺ and Pr³⁺ was synthesized on cleaned silicon (111) substrates by Sol-Gel route with a spin-coating technique. XRD patterns indicated that the films were crystallized into A-type Lu₂SiO₅ phase at 1000℃, followed by a phase transition to B-type Lu₂SiO₅ at 1100℃. SEM observations revealed that the surface of the films was smooth, homogeneous and crack-free when the samples were calcined under 1100℃. The average grain size of the crystal particles was 200-300 nm and the thickness of the thin film was about 320 nm when the coating layer number up to 10. The energy transference from Pr³⁺ to Ce³⁺ in Lu₂SiO₅ host was observed and discussed. The luminescence intensity of Ce³⁺ can be improved after Pr³⁺ co-doping.

Eu²⁺ activated Ba₃Si₆O₁₂N₂ oxynitride green phosphors were synthesized by microwave sintering method with the aid of fluxes, namely BaCl₂, H₃BO₃, KF, and NH₄F. We employed a combination of X-ray diffraction, photoluminescence spectra and scanning electron microscopy measurements, in conjunction with detailed quantum efficiency (QE), life time and thermal quenching studies of luminescence properties to understand the origins of the improved luminescence properties. The results showed that the photoluminescence intensity of the phosphors was increased obviously by using varied fluxes and the intensity rise was recorded in order of fluxes as following: H₃BO₃ > KF > BaCl₂ > no flux > NH₄F. The maximum emission intensity of the Ba₃Si₆O₁₂N₂:Eu²⁺ phosphor was achieved at containing 1.0wt% H₃BO₃, due to the high crystallinity, narrow particle-size distribution and smooth surface, which showed low thermal quenching, shorter life time and increased external quantum efficiency, compared with that of the sample with other fluxes or without flux.

Effect of residual phase and grain size the corrosion resistance of SiC ceramics in mixed HF-HNO₃ acid solution was investigated. Three kinds of fabrication methods (SSiC-solid state sintered SiC, LPS SiC-liquid phase sintered SiC and RB SiC-reaction bonded SiC) were adopted to prepare SiC ceramics. Besides, the grain size in SiC ceramics was adjusted under different sinter temperatures. Compared to RB SiC and LPS SiC ceramics, SSiC ceramics showed a better corrosion resistance for the good corrosion resistance of residual graphite and ‘island’ structure of residual phase in ceramics. The grain size of SiC ceramics sintered at temperature between 2100℃ and 2160℃ increase from 2 μm to 6 μm, and the absolute values of Y intercept, which reflect the corrosion of SSiC ceramics with none residual phase, are 9.22 μg/cm² (2100℃), 5.81 μg/cm² (2130℃) and 0.29 μg/cm² (2160℃), which demonstrate that large grain size is beneficial to the corrosion resistance of SiC ceramics.

The porous nickel oxide microsphere on Ni foam was adopted to optimize the charge transfer process to improve electrochemical performance by a microwave-assisted method. Microstructure and morphologies of the resulting materials were investigated by X-ray diffraction, scanning electron microscope, transmission electron microscope. Results showed that the as-prepared NiO microspheres with nickel sulfate had average diameter of ~2 µm. The ultrathin secondary nanoflakes composed of nanowire building blocks were interconnected with each other forming a highly open net-structure. Because of enhanced electron transfer capability, charge transfer resistances of the porous microsphere were reduced and the electrochemical performances were improved, the charge-discharge measurements tested at a discharge current of 0.5 A/g showed higher rate specific capacitance (455 F/g). The impedance characterization illustrated lower electronic and ionic resistance of porous NiO due to its superior surface properties for enhanced electrode electrolyte contact during the faradaic redox reactions.