Mid-Temperature Synthesis of CeO2-TiO2 Complex Compound and Its XRD Structure Study

TiO2 andCeO2 aresemiconductormaterials .TiO2hasthepropertiesofphoto catalysis[1] whileCeO2 hastheabilityofoxygenstorageandcanpromotethedispersionofprecionsmetalsonthesupporter[2 ] .CeO2 TiO2 com plexcompoundwasusedascatalystandspecialfunction almaterial[3～ 5] .ThetraditionalsynthesisofCeO2 TiO2complexcompoundisbyceramicmethodthatusesoxidesasrawmaterialsanditiscalcinedabove 130 0℃[6～ 8] .However ,thestructureandmicrostructureofthecomplexcompoundarenotsuitableforcatalystandfunctionalm…     

Influence of manganese rate on structural,optical and electrochemical properties of CeO2 thin films deposited by spray pyrolysis: Supercapacitor applications

The present work aimed to investigate the electrochemical properties of ITO substrates in propylene carbonate (PC) with 0.5 mol/L lithium perchlorate (LiClO₄) medium in the presence of elaborated thin films of cerium dioxide pure and doped with manganese at varying percentages. Ce_1–xMn_xO₂ (x = 0 wt%, 2 wt%, 4 wt% and 6 wt%) were successfully deposited by the spray pyrolysis (SP) technique on the glass substrate and ITO at 450 °C. The effects of manganese (Mn) doped thin films Ce_1–xMn_xO₂ were studied and investigated by using different analyses namely X-ray diffraction (XRD) analysis, Raman spectroscopy method, UV–Vis spectrophotometer technique, atomic force microscopy (AFM) analysis and electrochemical properties. XRD data obtained present a polycrystalline with a face-centred cubic structure of fluorite type. Raman results of undoped and Mn doped thin films show two peaks at 465 and 600 cm^?1, due to the formation of extrinsic oxygen vacancies by the incorporation of Mn into Ce_1–xMn_xO₂ matrix. Energy dispersive spectroscopy (EDS) data show the presence of Ce, O, and Mn elements in the elaborated films. The AFM results reveal that the surface roughness decreases with increasing Mn rate. Further, band gap energy of thin films decreases with increasing in Mn rate due to the formation of defect state between valence and conduction band. The storage capacity of the elaborated Ce_1–xMn_xO₂/ITO/PC + LiClO₄ electrode reaches a maximum of 1.997 mF in the presence of 6 wt% of Mn.     

Preparation and characterization of CeO2 doped ZnO nano-tubes fluorescent composite

ZnO nanotubes were hydrothermally synthesized and the ZNTs/CeO2 fluorescent composite were prepared by introducing nano CeO2 particles into ZnO nano-tubes via a chemical solution adsorption and annealing process. The samples were characterized by X-ray diffraction, scanning electron microscopy, Fourier transformation infrared spectroscopy and room temperature photoluminescence measurement. Due to the interaction between Ce4+ and the surface atoms of ZnO2 nano-tubes, a photoluminescence enhancement was obser...     

Structural characterization and corrosive property of Ni-P/CeO2composite coating

Electroless Ni-P/nano-CeO2 composite coating was prepared in acidic condition, and its microstructure and corrosive property were compared with its CeO2-free counterpart. Scanning electronic microscopy (SEM), transmission electronic microscopy (TEM), X-ray diffraction spectrometer (XRD), and differential scanning calorimeter (DSC) were used to examine surface morphology and microstructure of the coating. Corrosive investigation was carried out in 3%NaCl+5%H2SO4 solution. The results showed that Ni-P coating had partial amorphous structure mixed with nanocrystals, whereas the Ni-P/CeO2 coating had perfect amorphous structure. In high temperature condition, Ni3P precipitation and Ni crystallization occurred in both coatings but at different temperatures, whereas the Ni-P/CeO2 coating had sintered phase of NiCe2O4 spinels. The anticorrosion property and passivity were improved in the CeO2-containing coating due to its less liability to undergo local-cell corrosion than its CeO2-free counterpart. During the co-deposition process, some Cen+ (n=3, 4) ions may be adsorbed to the metal/solution interface, hinder nickel's crystal-typed deposition and promote phosphorous deposition. The nano-CeO2 doping finally resulted in the coating' perfect amorphous structure and good anti-corrosive property.     

Structural, electrical and surface morphological studies of Cd2SnO4 and Mg doped Cd2SnO4 thin films

The technologically important conductive Cadmium stannate (Cd₂SnO₄) and Magnesium doped cadmium stannate (Cd₂SnO₄: Mg) thin films were prepared using Cadmium acetate and stannous chloride by spray pyrolysis technique. Films prepared are crystalline and have cubic CdO phase with SnO₂. The X-ray diffraction patterns of both thin films shows perfect crystalline structure and from the data, the particle diameter of both films were calculated. Atomic Force Microscopy (AFM) of both films reveals the uniform thickness of the films and the presence of uniform grain growth in Cd₂SnO₄ and Mg doped Cd₂SnO₄ thin films. Thickness of Cadmium stannate film is 725nm and that of Magnesium doped Cadmium stannate film is 285nm. The indirect band gap energy of Cd₂SnO₄ film is 2.71eV and for magnesium doped Cd₂SnO₄ is 2.97eV were observed from the UV-Visible absorption spectrum studies. Presence of uniform grain growth is found in both thin films. The doping of Magnesium in Cadmium stannate film improves the electrical properties without affecting its structural properties.     

Preparation,characterization and catalytic oxidation property of CeO2/Cu2+- attapulgite (ATP) nanocomposites

Cerium oxide (CeO₂) coated on copper modified attapulgite clay nanocomoposite (CeO₂/Cu²⁺-ATP) was prepared by homogeneous deposition method. The microstructures of the as-prepared CeO₂/Cu²⁺-ATP nanocomposites were characterized by X-ray diffraction (XRD), energy-dispersive spectrometer (EDS) and transmission electron microscopy (TEM). The results indicated that CeO₂ particles with average size of about 5 nm were loaded onto the Cu²⁺-ATP and were widely dispersed. Comparing the catalytic activity of ATP/CeO₂ and CeO₂/Cu²⁺-ATP, the catalytic activity was improved when a small quantity of Cu²⁺ was introduced. The loading amount of CeO₂ and reaction temperature had important effects on decolorization ratio of methyl orange (MO). When the loading amount and reaction temperature were 70% and 338 K, respectively, the decolorization ratio of MO reached over 99%, which showed excellent catalytic activity.     

Synthesis and characterization of yttrium and antimony codoped SnO2 conductive nanoparticles

Y was used as a dopant in preparing conductive powder to improve its performance. Y and Sb co-doped SnO₂ conductive nanoparticles were prepared by the complexation-coprecipitation method with Sn, Sb₂O₃ and Y₂O₃ as the raw materials. Crystal phase, thermal behavior and structure of the prepared conductive nanoparticles were characterized by X-ray diffraction (XRD), thermal analysis (TG-DSC), Fourier transform infrared (FTIR) and transmission electron microscopy (TEM) techniques, respectively. The Y and Sb co-doped SnO₂ conductive nanoparticles with a structure of tetragonal rutile had intense absorption in 4000-2500 cm^?1, and the diameter ranged from 10 to 30 nm. The resistivity of Y and Sb co-doped SnO₂ conductive nanoparticles was as low as 0.09 Ω·cm which was 4.6 times lower than that of Sb doped SnO₂ conductive nanoparticles.     

纳米(CeO2)0.95(GdO1.5)0.05材料的制备与电化学性能

采用改进的氨水-双氧水法制备了纳米(CeO2)0.95(GdO1.5)0.05粉末,并利用TGA/DTA、XRD和TEM对粉末进行了表征。由TGA/DTA分析曲线可知,粉末在621℃完全转化为晶态(CeO2)0.95(GdO1.5)0.05;XRD分析表明,粉末样品为萤石结构,计算得粉末的粒度为5.23nm,晶胞常数为0.5406nm;由TEM照片可以看出,粉末呈软团聚状,颗粒细小均匀,粒径分布在5～10nm范围内,与XRD的分析计算结果基本一致。用SPS法制备了纳米(CeO2)0.95(GdO1.5)0.05固体电解质材料,采用交流阻抗法测试其电导率,晶格电导率为1.32E-3S/cm,晶界电导率为0.24E-5S/cm,与普通材料相比,纳米材料的晶格电导率提高了两倍,晶界电导率提高了100多倍,但晶界电导仍小于晶格电导,即晶界仍然是阻抗性的。     

Transition metal doping effect and high catalytic activity of CeO2–TiO2 for chlorinated VOCs degradation

A series of transition metals (Fe, Co, Ni, Cu, Cr and Mn)-doped CeO₂–TiO₂ catalysts were prepared by the sol–gel method and applied for the catalytic removal of 1,2-dichloroethane (DCE) as a model for chlorinated VOCs (CVOCs). The various characterization methods including X-ray diffraction (XRD), N₂ adsorption–desorption, UV-Raman, NH₃ temperature-programmed desorption (NH₃-TPD) and H₂ temperature-programmed reduction (H₂-TPR) were utilized to investigate the physicochemical properties of the catalysts. The results show that doping Fe, Co, Ni or Mn can obviously promote the activity of CeO₂–TiO₂ mixed oxides for DCE degradation, which is related to their improved texture properties, acid sites (especially for strong acidity) and low-temperature reducibility. Particularly, CeTi–Fe doped with moderate Fe exhibits excellent activity for 1,2-dichloroethane (DCE) degradation, giving a T_90% value as low as 250 °C. More importantly, only trace chlorinated byproducts were produced during the low-temperature degradation of various CVOCs (dichloromethane (DCM), trichloroethylene (TCE) and chlorobenzene (CB)) over CeTi–Fe1/9 catalyst with high durability.     

Synthesis and characterization of Co_(1-2x)Ni_xMn_xCe_yFe_(2-y)O_4 nanoparticles

Spinel ferrite Co_(1-2 x)Ni_xMn_xFe_(2-y)Ce_yO_4(0.0≤x=y≤0.3) nanoparticles(NPs) were prepared by sol-gel auto-combustion method.The synthesized NPs were examined using several techniques such as X-ray diffraction(XRD),field emission scanning electron microscopy(FE-SEM) coupled with EDX and elemental mapping,transmission electron microscopy(TEM),Fourier-transform infrared spectroscopy(FT-IR),and a vibrating sample magnetometer(VSM).The analysis of the crystal structure and the phase identification of samples indicates the formation of spinel cubic phase with the occurrence of CeO_2 as secondary phase when the content of Ce substitution element increases.In addition,all produced samples exhibit cubic symmetry with space group Fd3m.TEM confirms the presence of two phases,i.e.,the cubic spinel ferrite and the cubic cerium oxide(CeO_2).The characteristics of hysteresis loops reveal the soft ferrimagnetic nature of the different synthesized samples.The saturation(M_s) and remanent(M_r) magnetizations fall on increasing the content of substituting elements.Compared with pure CoFe_2O_4 NPs,the value of coercive field(H_c) slightly increases for x=y=0.1 and x=y=0,2 NPs.Then,H_c reduces with further increasing the x and y contents.The squareness ratio is found to be in the 0.528-0.400 interval,indicating the single domain NPs with uniaxial anisotropy for the different produced NPs.The magneto crystalline anisotropy constant(K_(eff)),anisotropy field(H_a),magneton number(n_B) and the demagnetizing field(N) were also determined and discussed.     

Improved sulfur-resistant ability on CO oxidation of Pd/Ce0.75Zr0.25O2 over Pd/CeO2-TiO2 and Pd/CeO2

The influence of sulfation on Pd/Ce0.75Zr0.25O2, Pd/Ce O2-Ti O2 and Pd/Ce O2 was investigated. Physical structure and chemical properties of different catalysts were characterized by N2 adsorption, X-ray diffraction(XRD), CO chemisorption, X-ray photoelectron spectroscopy(XPS), Fourier transform infrared spectroscopy(FT-IR) and X-ray fluorescence(XRF). After 10 h SO2 sulfation, it was found that the decrement on CO oxidation catalytic activity was limited on Pd/Ce0.75Zr0.25O2 compared to Pd/Ce O2-Ti O2 and Pd/Ce O2. It demonstrated that Pd/Ce0.75Zr0.25O2 was more sulfur resistant compared to the other two catalysts. After sulfur exposure, catalyst texture was not much influenced as shown by N2 adsorption and XRD, and surface Pd atoms were poisoned indicated by CO chemisorption results. Pd/Ce0.75Zr0.25O2 and Pd/Ce O2-Ti O2 exhibited less sulfur accumulation compared to Pd/Ce O2 in the sulfation process. Furthermore, XPS results clarified that surface sulfur amount, especially surface sulfates amount on the sulfated catalysts was more crucial for the deactivation in sulfur containing environment.     

Synthesis and biological investigations of 2-(tetrahydropyran-2'-yl) and 2-(tetrahydrofuran-2'-yl)benzimidazoles

A set of benzimidazole derivatives bearing on position 2 a tetrahydropyranyl or tetrahydrofuranyl residue was prepared and tested for antitumoral, anti HIV-1 and other pharmacological activities. While the anti-HIV activity was completely lacking, moderate antitumoral activity was found in a few compounds; particularly the 5,6-dichloro-2-(tetrahydropyran-2-yl)-benzimidazole (8) was able to inhibit the growth of 19 cell lines of humane tumors at near micromolar concentration. On the other hand compounds 4, 6-8 and 10 exhibited significant tracheal relaxant activity in vitro at concentration 3-10 micrograms/ml, thus resulting superior to theophylline and comparable to amrinone.     

Synthesis of RE-Ag, Al-RE-doped sol-gel glass and films for solar cells

The paper dealt with the study of fluorescence properties of sol-gel systems doped with rare-earth ions and co-doped with silver. The general problem for these types of inorganic phosphors was a very low absorbance in the visible range. Therefore, a sensitizer of luminescence of the rare-earth ions should be selected and used. The sensitizer should possess a good absorbance in the visible range and strong interaction with the rare-earth ions. In this study silver ions were selected as the sensitizer.     

Study on vacuum ultraviolet spectra of amorphous Er_2O_3 films on Si（001） substrates

Amorphous Er2O3 films have been fabricated on p-type Si(001) substrates using radio frequency magnetron sputtering technique. Vacuum ultraviolet spectra were employed to investigate the samples. An optical gap of 6.17 eV for Er2O3 films was obtained from the ab-sorption coefficient spectra. A possible reason was put forward to explain the inconsistent results about the band gap of Er2O3 in literatures. Emission spectra exhibited a strong emission band at 494 nm with the incident ultraviolet light of 249 nm. The observed high density of emission bands of Er2O3 films in the visible wavelength indicated that Er2O3 films could be used in Si solar cells for increasing conversion efficiency.