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1.
Two-layer ZrO2/SiO2 and SiO2/ZrO2 films were deposited on K9 glass substrates by sol–gel dip coating method. X-ray photoelectron spectroscopy (XPS) technique was used to investigate the diffusion of ZrO2/SiO2 and SiO2/ZrO2 films. To explain the difference of diffusion between ZrO2/SiO2 and SiO2/ZrO2 films, porous ratio and surface morphology of monolayer SiO2 and ZrO2 films were analyzed by using ellipsometry and atomic force microscopy (AFM). We found that for the ZrO2/SiO2 films there was a diffusion layer with a certain thickness and the atomic concentrations of Si and Zr changed rapidly; for the SiO2/ZrO2 films, the atomic concentrations of Si and Zr changed relatively slowly, and the ZrO2 layer had diffused through the entire SiO2 layer. The difference of diffusion between ZrO2/SiO2 and SiO2/ZrO2 films was influenced by the microstructure of SiO2 and ZrO2. 相似文献
2.
The studies of ZrO2 and yttrium stabilized ZrO2 nanocrystals luminescence as well as yttrium stabilized single crystal luminescence and induced absorption showed that the intrinsic defects are responsible for luminescence at room temperature. These defects form a quasi-continuum of states in ZrO2 band gap and are the origin of the luminescence spectrum dependence on the excitation energy. Luminescence centers are oxygen vacancies related but not the vacancies themselves. At room temperature, in ZrO2, deep traps for electrons and holes exist. The oxygen vacancies are proposed to be the traps for electrons. 相似文献
3.
Samuel D. Jones 《Applied Surface Science》2010,256(24):7345-317
Three Cu/ZnO/ZrO2/Al2O3 methanol reforming catalysts were investigated using X-ray photoelectron spectroscopy (XPS). The catalysts which contained ZrO2 from a monoclinic nanoparticle ZrO2 precursor exhibit both a higher activity toward the methanol steam reforming reaction and a lower CO production rate compared to catalysts composed of an XRD-amorphous ZrO2 produced by impregnation using a Zr(NO3)2 precursor. The presence of a monoclinic phase appears to result in an increased charge transfer between the Zr and Cu species, as evidenced by a relatively electron-rich ZrO2 phase and a partially oxidized Cu species on reduced catalysts. This electron deficient Cu species is more reactive toward the methanol reforming reaction and partially suppresses CO formation through the reverse water gas shift or methanol decomposition reactions. 相似文献
4.
The surface properties and the activities in catalytic wet air oxidation over CeO2-TiO2 catalysts 总被引:1,自引:0,他引:1
Shaoxia Yang Wanpeng Zhu Zhanpeng Jiang Zhengxiong Chen Jiangbing Wang 《Applied Surface Science》2006,252(24):8499-8505
No-noble metal CeO2-TiO2 catalysts prepared by sol-gel method were developed and examined for catalytic wet air oxidation (CWAO) of acetic acid. The structure of the catalysts was measured by BET, SEM, XRD, XPS and DTA-TG. We investigated the effect of the interactions of Ce and Ti on the structure of CeO2-TiO2 catalysts. The mechanisms of the relationships between the different content of Ti and the activity of CeO2-TiO2 catalysts were discussed. The results showed that the average crystal size of CeO2 decreased and the surface areas increased; the low valence of Ce3+ increase, and the chemisorbed oxygen slightly decreased with the increase of Ti content on the surface of CeO2-TiO2 catalysts. The order of the activity in CWAO of acetic acid followed: Ce/Ti 1/1 > Ce/Ti 3/1 > Ce/Ti 1/3 > Ce/Ti 5/1 > CeO2 > TiO2 > no catalyst. In CWAO of acetic acid, the optimal atomic ratio of Ce and Ti was 1, and the highest COD removal was over 64% at 230 °C, 5 MPa and 180 min reaction time over Ce/Ti 1/1 catalyst. The excellent activity and stability of CeO2-TiO2 catalysts was observed in our study. 相似文献
5.
A new type of multicoated silica/zirconia/silver (SiO2/ZrO2/Ag) core-shell composite microspheres is synthesized in this paper. In the process, ZrO2-decorated silica (SiO2/ZrO2) core-shell composites were firstly fabricated by the modification of zirconia on silica microspheres through the hydrolysis of zirconium precursor. Subsequently, on SiO2/ZrO2 composite cores, silver nanoparticles were introduced via ultrasonic irradiation and acted as “Ag seeds” for the formation of integrate silver shell by further reduction of silver ions using formaldehyde as reducer. The resulting samples were characterized by transmission electron microscopy, X-ray diffraction, Fourier-transform infrared, energy-dispersive X-ray, and UV-vis spectroscopy, indicating that zirconia and silver layers were successfully coated on the surfaces of silica microspheres. 相似文献
6.
A novel long-lasting afterglow phosphor ZrO2:Ti is prepared by the conventional solid-stated method and their luminescent properties are investigated. A bluish white strong and broad emissive band, which is attributed to originate from the recombination of electrons trapped by F+ centers and the holes created in Valence band, is observed under 254 nm UV irradiation. The identical color long afterglow, which lasts about 1 h, is found in the ZrO2:Ti phosphor after removing the 254 nm UV light. The mechanism of the long lasting phosphorescence (LLP) has been discussed based on the thermoluminescence (TL) results. The replacement of Zr by Ti produces more anion vacancies, resulting in the enhanced photoluminescence (PL) and LLP of ZrO2:Ti sample. These results indicate that ZrO2:Ti phosphor has potential promising applications. 相似文献
7.
O. Bethge C. Henkel S. AbermannG. Pozzovivo M. Stoeger-PollachW.S.M. Werner J. SmolinerE. Bertagnolli 《Applied Surface Science》2012,258(8):3444-3449
La2O3 grown by atomic layer deposition (ALD) and thermally grown GeO2 are used to establish effective electrical surface passivations on n-type (1 0 0)-Ge substrates for high-k ZrO2 dielectrics, grown by ALD at 250 °C substrate temperature. The electrical characterization of MOS capacitors indicates an impact of the Ge-surface passivation on the interfacial trap density and the frequency dependent capacitance in the inversion regime. Lower interface trap densities can be obtained for GeO2 based passivation even though a chemical decomposition of the oxidation states occur during the ALD of ZrO2. As a consequence the formation of a ZrGeOx compound inside the ZrO2 matrix and a decline of the interfacial GeO2 are observed. The La2O3 passivation provides a stable amorphous lanthanum germanate phase at the Ge interface but also traces of Zr germanate are indicated by X-ray-Photoelectron-Spectroscopy and Transmission-Electron-Microscopy. 相似文献
8.
In this study several complementary methods as XRD, HRTEM, O2 and H2 adsorption, as well as H2-O2 titration were used for characterization of the metallic phase in 0.5-3.0 wt.% Pt/ZnAl2O4 catalysts. Three nanocrystalline ZnAl2O4 spinels used as a supports were prepared by the solvothermal and co-precipitation method. It was found that irrespective of the preparation method they form very good support materials with a high capacity to achieve high platinum dispersion. O2 and H2 chemisorption data showed metal dispersion up to 90% and good correspondence with HRTEM results was observed. The H2-O2 titration method may be applied for determination of Pt dispersion only in the high-loaded Pt/ZnAl2O4 catalysts. The catalytic performances of Pt supported on the prepared spinels were evaluated in the propane total oxidation reaction. 相似文献
9.
S. Abermann C. Henkel O. Bethge G. Pozzovivo P. Klang E. Bertagnolli 《Applied Surface Science》2010,256(16):5031-5034
The impact of the ZrO2/La2O3 film thickness ratio and the post deposition annealing in the temperature range between 400 °C and 600 °C on the electrical properties of ultrathin ZrO2/La2O3 high-k dielectrics grown by atomic layer deposition on (1 0 0) germanium is investigated. As-deposited stacks have a relative dielectric constant of 24 which is increased to a value of 35 after annealing at 500 °C due to the stabilization of tetragonal/cubic ZrO2 phases. This effect depends on the absolute thickness of ZrO2 within the dielectric stack and is limited due to possible interfacial reactions at the oxide/Ge interface. We show that adequate processing leads to very high-k dielectrics with EOT values below 1 nm, leakage current densities in the range of 0.01 A/cm2, and interface trap densities in the range of 2-5 × 1012 eV−1 cm−2. 相似文献
10.
A series of CuO/CeO2 catalysts with different Cu-Ce compositions were synthesized by co-precipitation method and characterized by X-ray diffraction, H2-TPR, CO-TPD, SEM and X-ray photoelectron spectroscopy (XPS) techniques. The effects of Cu-Ce composition and water vapor on the catalytic properties for the selective CO oxidation in the hydrogen-rich gas were investigated. The results indicated that CuO (10%)/CeO2 catalyst remained the maximum CO conversion and selectivity at 140 and 160 °C, while the performance of CuO/CeO2 catalysts deteriorated with the CuO molar ratio further increased. The interfacial CuO and CeO2 interaction and synergistic effect enhanced the redox properties of CuO/CeO2 catalyst and the highly dispersed copper species were proposed as the active sites for the selective CO oxidation. The blockage of catalytic active sites by absorbed water and the formation of CO-H2O surface complexes reduced the activity of CuO (10%)/CeO2 catalyst. The decreasing of surface lattice oxygen and absorbed oxygen species and the agglomeration of copper particles were the plausible interpretations for the deactivation of CuO (10%)/CeO2 catalyst. 相似文献
11.
L.Y. Zhu 《Optics Communications》2008,281(9):2548-2551
Ni2+-doped ZrO2 precursor fibers were prepared via sol-gel technique by dry-spinning method and then heat-treated at different temperatures. The surface of the fibers is smooth with uniform diameter and no cracks have been observed by scanning electron microscopy (SEM). The emission intensity reaches a maximum value at 1 mol% Ni2+ because of the concentration quenching. The photoluminescence (PL) relative intensity is apparently intensifying with increasing temperature before 700 °C due to the crystallinity of the ZrO2 lattice improvement. The PL results show that the typical emission center is at 510 nm excited at 315 nm. 相似文献
12.
ZrO2 thin films were prepared by electron beam evaporation at different oxygen partial pressures. The influences of oxygen partial pressure on structure and related properties of ZrO2 thin films were studied. Transmittance, thermal absorption, structure and residual stress of ZrO2 thin films were measured by spectrophotometer, surface thermal lensing technique (STL), X-ray diffraction and optical interferometer, respectively. The results showed that the structure and related properties varied progressively with the increase of oxygen partial pressure. The refractive indices and the packing densities of the thin films decreased when the oxygen partial pressure increased. The tetragonal phase fraction in the thin films decreased gradually as oxygen partial pressure increased. The residual stress of film deposited at base pressure was high compressive stress, the value decreased with the increase of oxygen partial pressure, and the residual stress became tensile with the further increase of oxygen pressure, which was corresponding to the evolution of packing densities and variation of interplanar distances. 相似文献
13.
Nguyen Hoa Hong Chul-Kwon Park A.T. Raghavender Antoine Ruyter Ekaterina Chikoidze Yves Dumont 《Journal of magnetism and magnetic materials》2012
Theory has predicted that high temperature ferromagnetism (FM) should be found in cubic fake-diamonds, Mn-doped ZrO2. Experimentally, it is shown that Mn-doped ZrO2 ceramics are not ferromagnetic, but the nanosized Mn-doped ZrO2 thin films grown on LaAlO3 substrates can be ferromagnets with TC above 400 K. The largest saturated magnetic moment (Ms) is huge as of about 230 emu/cm3 for the Mn0.05Zr0.95O2 films, and it decreases as the Mn content increases. The intrinsic FM is strongly associated with the cubic structure of Mn-doped ZrO2, and the Mn–Mn interactions via oxygen intermediates are important. No electrical conductivity is observed. Mn-doped ZrO2 thin films can be truly considered as excellent candidates for spintronic applications. 相似文献
14.
Fibre laser surface treatment (FLST) of a cold isostatic pressed (CIP) ZrO2 engineering ceramic (ZEC) was performed using various processing gas compositions. This is the first time that a surface treatment of ZEC has been employed hitherto by using the fibre laser (FL) radiation to observe the changes on and within the surface of the engineering ceramic; in particular, material removal, surface topography, chemical composition, changes in the surface hardness and distribution of the heat affected zone (HAZ). Bonding of the grain boundaries was found through surface melting with all FL irradiated samples to some extent, but the effect was more marked on the sample FL irradiated with an Ar assist gas and proved to be the most effective combination for modifying the surface morphology. The surface finish and the material removal were varied with the changes in the gas composition. Maximum material removal was observed when an O2 assist gas was employed on account of the O2 generating an exothermic reaction. This in turn, produced excessive heating. The compositional analysis revealed a chemical change occurring within the FL irradiated surfaces, regardless of the assist gas used, with the ZEC transforming to zirconia carbide (ZrC). 相似文献
15.
采用溶胶-凝胶方法制备了ZrO2-TiO2(Ti含量为0—100mol%)高折射率光学薄膜. 借助激光动态光散射技术研究溶胶微结构. 采用傅里叶变换红外光谱、原子力显微镜、薄膜光学常数分析仪、漫反射吸收光谱及强激光辐照实验,对膜层的结构、光学性能及抗激光损伤性能进行了系统表征. 结果显示,溶胶-凝胶工艺可以在部分牺牲折射率的情况下,使膜层的抗激光损伤性能得到大幅度提升. 随Ti含量从0mol%增加至100mol%,膜层的平均损伤阈值呈下降趋势,当Ti含量从0mol%增加至60mol%时,平均损伤阈值从57.1J/cm2下降到21.1J/cm2(辐照激光波长为1053nm,脉冲宽度为10ns,“R/1”测试模式),当Ti含量从60mol%增加至100mol%时,平均损伤阈值变化很小. 综合溶胶微结构、膜层光学性能和损伤实验结果可以推断,强激光诱导多光子吸收是引起膜层损伤的主要原因. 不同配比的复合膜之间光学带隙的显著差异导致相同辐照激光情况下多光子吸收的概率发生变化,从而导致损伤阈值的规律性变化.
关键词:
2-TiO2薄膜')" href="#">ZrO2-TiO2薄膜
溶胶-凝胶
激光诱导损伤
光学带隙 相似文献
16.
Metal-insulator-metal (MIM) capacitors were fabricated using ZrO2 films and the effects of structural and native defects of the ZrO2 films on the electrical and dielectric properties were investigated. For preparing ZrO2 films, Zr films were deposited on Pt/Si substrates by ion beam deposition (IBD) system with/without substrate bias voltages and oxidized at 200 °C for 60 min under 0.1 MPa O2 atmosphere with/without UV light irradiation (λ = 193 nm, Deep UV lamp). The ZrO2(∼12 nm) films on Pt(∼100 nm)/Si were characterized by X-ray diffraction pattern (XRD), field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HRTEM), capacitance-voltage (C-V) and current-voltage (I-V) measurements were carried out on MIM structures. ZrO2 films, fabricated by oxidizing the Zr film deposited with substrate bias voltage under UV light irradiation, show the highest capacitance (784 pF) and the lowest leakage current density. The active oxygen species formed by UV irradiation are considered to play an important role in the reduction of the leakage current density, because they can reduce the density of oxygen vacancies. 相似文献
17.
Electrochemical oxidation of methanol on Pt nanoparticles composited MnO2 nanowire arrayed electrode
Guang-Yu Zhao 《Applied Surface Science》2008,254(10):3232-3235
By use of the membrane-template synthesis route, MnO2 nanowire arrayed electrodes are successfully synthesized by means of the anodic deposition technique. The Pt nanoparticles composited MnO2 nanowire arrayed electrodes (PME) are obtained through depositing Pt on MnO2 nanowire arrayed electrode by cathode deposition technique. For comparison of electrochemical performance, Pt nanowire arrayed electrodes which have the same amount of Pt with PME are also prepared. The electro-oxidation of methanol on PME and Pt nanowire arrayed electrodes is investigated at room temperature by cyclic voltammetry, which show that about 110 mV decreased overpotential and 2.1-fold enhanced votammetric current are achieved on PME. The chronoamperometry result demonstrates that the resistance to carbon monoxide for PME is improved. 相似文献
18.
19.
Sol-gel (ZrO2/SiO2)12 ZrO2 films were prepared by spin coating method. The reflectivity spectrum of the films was measured with a Lambda 900 spectrometer. In order to investigate laser-induced damage threshold (LIDT) characteristic of highly reflective films, one-layer ZrO2 and SiO2 films, two-layer ZrO2/SiO2 and SiO2/ZrO2 films were also prepared by spin coating method. LIDT of each film was measured. Damage morphology after laser irradiation was characterized by optical microscopy (Nikon E600K). The experimental results showed that the reflectivity of (ZrO2/SiO2)12 ZrO2 film at 1064 nm and 355 nm wavelength is 99.7%. The LIDT results decreases as the number of layer of films increases. All the films have similar damage morphology. The experimental results are explained by the different temperature profiles of the films. 相似文献
20.
Nannan SunXia Wen Feng WangWeicai Peng Ning ZhaoFukui Xiao Wei Wei Yuhan Sun Jinting Kang 《Applied Surface Science》2011,257(21):9169-9176
Ni-CaO-ZrO2 catalysts for CO2 reforming of CH4 were prepared by either co-precipitation or impregnation and characterized by means of N2 adsorption-desorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and temperature programmed (TP) techniques. It was found that the preparation procedure greatly influenced the physicochemical properties of catalysts, such as morphology, phase and surface structure. As a result, their activity in CO2 reforming of CH4 was determined by the dispersion of Ni and the co-precipitated catalysts showed a better stability. Furthermore, CO2-TPD and transient pulse experiments suggested that the carbon formed over two co-precipitated catalysts was eliminated by different mechanisms, and redox properties and strong basicity were believed to be the key factor for the stability, respectively. 相似文献