Toward nanograined gadolinia doped ceria via two-step sintering at ultralow temperature and its electrical conductivity

Highly dense (>98%) and nanograined (∼60 nm) gadolinia doped ceria are obtained from ultrafine powders by adopting two-step sintering (TSS) procedure at an ultralow temperature of 750 °C with a dwell time of 20 h, which is the lowest sintering temperature for ceria family without sintering aids up to now. Electrochemical impedance spectroscopy investigations suggest that the electrical conductivities of densified electrolytes are closely related to sintering temperature and grain size, and GDC900-750 exhibits the highest total electrical conductivity of 3.640 S m⁻¹ at 700 °C in air. Fitting calculation indicates partial grain-size dependence of oxygen vacancy association enthalpy and grain-size independence of oxygen ion migration enthalpy. Grain boundary maturity influences on grain boundary conductivity to some extent, and younger grain boundary endues the densified electrolytes with higher grain boundary conductivity.     

掺锑氧化锡纳米粉体的制备与表征

以SnCl4·5H2O和SbCl3为原料,NH3为共沉淀剂,在表面活性剂存在下,采用室温固相法制备锑掺杂二氧化锡(ATO)纳米粉体。探讨了掺锑量、表面活性剂对ATO粉体性能的影响。运用IR、XRD、TEM、比表面仪(BET)等对ATO粉体进行了表征。结果表明,当锑掺杂量为12.3%时,ATO纳米粉体具有最小电阻率,为3.36Ω·cm,ATO粉体为四方晶红石结构,颗粒形状为近似球形,粒度均匀,一次粒径为10 nm左右。     

Sr_3SiO_5：Eu~（2＋）荧光粉相形成的影响因素及发光特性

采用高温固相法制备Sr3SiO5：Eu2＋荧光粉,利用X射线衍射分析方法和光致光谱分析方法研究样品的物相组成、激发光谱和发射光谱。研究摩尔比n（Sr）/n（Si）、助熔剂BaF2质量、煅烧温度及Eu2＋掺量等对样品物相形成和发光性能的影响。结果表明最佳实验参数为：n（Sr）/n（Si）=3、BaF2为1%、煅烧温度为1...     

Gd~（3＋）掺杂SiO_2/TiO_2的制备及降解活性（英文）

采用溶胶-凝胶法制备Gd3＋掺杂SiO2/TiO2（Gd3＋-SiO2/TiO2,GST）。用X射线衍射（X-ray diffraction,XRD）仪、热重-差热分析仪、紫外-可见分光光度计（ultraviolet-visible spectrophotometry,UV-Vis）及X射线光电子分光仪（X-ray p...     

Enhanced photoluminescence property and mechanism of Eu3+‐doped tellurite glasses by the silver and gold nanoparticles

In this work, the silver or gold nanoparticle single‐existing and co‐existing tellurite glasses doped with Eu³⁺ were prepared, and the influence of gold or silver nanoparticles on the photoluminescence of tellurite glasses doped with Eu³⁺ were investigated. The photoluminescence of tellurite glasses doped with Eu³⁺ was enhanced by the surface plasmon absorption of gold or silver nanoparticles, and the maximum luminescence enhancement factors caused by the silver and gold nanoparticles are 4.8 and 3.5 factors, respectively. The differentiation of luminescence enhancement mechanisms caused by the gold or silver nanoparticles was demonstrated. The enhanced luminescence mechanism of the Au nanoparticle single‐existing tellurite glasses doped with Eu³⁺ was from the increasing of radiative decays rate caused by the Au nanoparticles. The excitation field enhancement caused by the Ag nanoparticles was responsible for the luminescence enhancement of the Ag single‐existing tellurite glasses doped with Eu³⁺. About 4.2‐factor luminescence enhancement was observed in the Ag and Au nanoparticle co‐existing tellurite glasses doped with Eu³⁺, which is attributed to the increasing of radiative decays rate and excitation field enhancement caused by the Au and Ag nanoparticles.     

Optoelectronic performances on different structures of Al‐doped ZnO

ZnO films and Al‐doped ZnO (AZO) films were deposited on p‐Si substrate by magnetron sputtering to investigate its chemical composition, structural and photoelectric properties. XRD and FTIR show that Al ions can enter into the substitutional and interstitial site of ZnO crystal, and O atoms in AZO films are more abundant. Three different structures of Al‐doped ZnO (substitutional Al, interstitial Al, and O‐rich Al‐doped ZnO) were built using first‐principles method based on experimental results, charge density difference, and density of States (DOS) illustrate that there are strong ionic interactions between Al and O atoms in substitutional Al‐doped ZnO, moreover, substitutional and interstitial Al doping both are beneficial to N type, but oxygen‐enriched ZnO is not conducive to N type. Furthermore, the optical properties of 3 different Al‐doped ZnO structures were investigated respectively. Compared with pure ZnO, the real and imaginary part of dielectric function of O‐rich and interstitial Al have a significant increase and move to lower energy (red shift), the reflectivity of O‐rich is 3 times of pure ZnO and substitutional Al‐doped ZnO. The results are hoped to be helpful to study AZO thin film and predict the properties of Al‐doped ZnO.     

Sn4+掺杂CuFe2O4有效降解亚甲基蓝染料废水的研究

以凝胶-溶胶法制备了不同含量Sn4+掺杂CuFe2O4样品,利用X 射线粉末衍射(XRD)、扫描电子显微镜(SEM)对样品的晶体结构和微观形貌进行了表征.以亚甲基蓝(MB)为目标降解物,考察了不同含量Sn4+掺杂CuFe2O4样品的催化效果.研究表明:Sn4+掺杂量为5%时,所制样品有好的结晶度.当5% Sn4+掺杂CuFe2O4用量为0.02 g,过氧化氢用量为0.2 mL,温度298 K,反应时间为120 min时,50 mg/L亚甲基蓝溶液的脱色率可达85%.动力学研究表明其降解过程近似为一级反应,反应速率常数达0.0155 min-1.     

BDD anodic oxidation as tertiary wastewater treatment for the removal of emerging micro‐pollutants,pathogens and organic matter

This work reports for the first time the removal of 17α‐ethynylestradiol (EE2), a synthetic estrogen hormone, from secondary treated effluents by electrochemical oxidation. Experiments were conducted in a single compartment reactor comprising a boron‐doped diamond (BDD) anode and a zirconium cathode. EE2, in the range 100–800 µg L^?1, was spiked in the post‐chlorination effluent of a municipal treatment plant and oxidized at 0.9–2.6 mA cm^?2 current density. Complete degradation of 100 µg L^?1 EE2 was achieved in 7 min at 2.1 mA cm^?2 and inherent conditions, while the addition of 0.1 mol L^?1 NaCl achieved removal in just a few seconds. The process was then tested in the pre‐chlorination effluent at 2.1 mA cm^?2 and inherent conditions; complete E. coli killing and EE2 removal occurred in just 1.5 and 3.5 min, respectively, while overall estrogenicity (assessed by the YES assay) and residual organic matter (in terms of chemical oxygen demand (COD)) decreased by 50% and 85% after 30 min, respectively. These results clearly show the potential of BBD electrochemical oxidation to serve as an efficient tertiary wastewater treatment. Copyright © 2011 Society of Chemical Industry     

Electrochemical Performance of PrBaCo2O5+δ and Sm0.5Sr0.5CoO3−δ Infiltrated Ce0.9Gd0.1O1.95 Cathodes

Cathodes with PrBaCo₂O_5+δ (PBC) and Sm_0.5Sr_0.5CoO_3−δ (SSC) infiltrated on Ce_0.9Gd_0.1O_1.95 (CGO) backbones are prepared using metal nitrates as precursors and ethanol as wetting agent. Electrochemical impedance spectra (EIS) are measured from cathode/CGO/cathode symmetrical cells in 400–650 °C under humidified air. The results indicate that interfacial area specific resistance (ASR) value decreases and then increases with infiltrate loading and minimum values occur at 50 wt.% loading (relative to sum of infiltrate and backbone) for both PBC and SSC infiltrates. ASR values of PBC infiltrated cathodes are lower than that of corresponding SSC infiltrated cathodes in general, and in particular ASR values as low as 1.36 × 10⁻² and 2.27 × 10⁻² Ω cm² are obtained at 650 °C in air for 50 wt.% PBC and 50 wt.% SSC infiltrated cathodes, respectively. Conductivity values of CGO electrolyte increase with infiltrate loading and agree with the reported values when the loading reaches 50 wt.%.