Ni~(2+)复合MOF-5材料的制备工艺及其电化学性能研究

金属有机框架材料(Metal organic frameworks,MOFs)由于具有超高的比表面积和可调的孔结构,已成为超级电容器电极材料的研究热点。以硝酸锌(Zn(NO_3)_2·6H_2O)和对苯二甲酸(C_6H_4(COOH)_2,BDC)为原料,采用水热法制备了MOF-5材料,并将MOF-5与不同比例的Ni~(2+)复合制备了Ni-MOF-5复合材料。用扫描电镜(SEM)和X射线衍射分析仪(XRD)对材料的表面形貌和结构进行了表征,采用Princeton和Arbin超级电容器测试系统对材料的电化学性能进行了测试。结果表明:复合不同比例的Ni~(2+)可获得不同形貌的Ni-MOF-5复合材料,当Ni~(2+)∶Zn~(2+)=0.50∶1.00(物质的量比)时,制得形貌均匀的微球富Ni颗粒,且其电化学性能优良,在电流密度为0.05 A/g的条件下,比容量达到400 F/g。     

n-NdF3制备、表征及对尿酸的电化学检定

采用水热法合成稀土纳米材料NdF₃（n-NdF₃）,并用于构建生物传感器实现对尿酸的电化学检定.首先利用扫描电子显微镜（SEM）、X-射线衍射（XRD）以及能谱分析（EDS）对所制备的材料进行结构表征和组成分析,并通过循环伏安（CV）和电化学阻抗（EIS）技术对修饰过程进行表征.详细研究尿酸在不同电极上的电化学行为.随后将生物传感器用于对多巴胺和尿酸的同时检定时,结果表明,在两者共存的情况下出现分离效果较好的2个氧化峰.这说明所制备的n-NdF3对尿酸具有高的灵敏性和好的催化活性.生物传感器能用于对多巴胺和尿酸的同时检定.      

热压烧结制备Li3/8Sr7/16Ta3/4Hf1/4O3钙钛矿型固体电解质

采用热压烧结制备了Li_3/8Sr_7/16Ta_3/4Hf_1/4O₃钙钛矿型固体电解质, 研究了不同烧结方式对样品性能的影响。通过X射线衍射仪表征材料的晶体结构, 扫描电子显微镜观察组织形貌, 交流阻抗仪测试电化学性能。结果表明:样品为立方KTaO₃相, 热压烧结成功合成了钙钛矿结构固体电解质, 相对于常压烧结, 热压烧结制备的样品孔隙更少, 晶粒之间结合更加紧密, 致密度高达94.0%, 离子电导率为4.33×10-4S·cm(T=298K).      

ABO_3型稀土复合氧化物结构特征和导电性的研究

用Ｘ－射线光电子能谱（ＸＰＳ）对钙钛矿型稀土复合氧化物ＬａＭＯ３（Ｍ＝Ｃｒ、Ｆｅ、Ｃｏ、Ｎｉ）的结构性质进行了表征，发现ＬａＭＯ３中金属离子Ｍ的ｄ电子具有程度不同的离域性，且随着Ｍ的不同，离域程度递变规律为ＬａＮｉＯ３＞ＬａＣｏＯ３＞ＬａＣｒＯ３＞ＬａＦｅＯ３，这与其导电性大小顺序相一致。     

电化学法和沉淀法制备的纳米结构CeO_2的微观结构比较

利用X射线衍射、X射线小角散射、扫描电子显微镜、透射电子显微镜等分析手段对电化学法、沉淀法制备的纳米结构的CeO2 的微观结构进行了比较 ,发现电化学法制备CeO2 是由分散的纳米颗粒组成 ,而沉淀法制备的CeO2 则是由粗大片状颗粒组成 ,而该片状颗粒具有纳米的结构。电化学法的CeO2 比沉淀法CeO2 具有更细的纳米结构     

原位热聚合制备PVC-SN共混固态电解质及其性能

固态电解质的低离子电导率和不稳定的电解质/电极界面是阻碍固态锂电池发展的关键问题。本文采用原位热聚合法制备聚碳酸亚乙烯酯(PVC)和丁二腈(SN)共混固态电解质,研究SN对PVC固态电解质本征性能以及固态电解质/电极界面稳定性的影响。研究结果表明:具有较好抗氧化性的SN均匀地分布在固态电解质内部,促进锂盐解离的同时提高聚合物链段运动能力,实现对离子导电网络的增强。引入SN后,室温离子电导率从2.4×10^?6 S/cm提升至1.213×10^?3 S/cm,氧化分解电位从4.58 V提升至5.52 V。当w(SN)为10%时展现出优异的循环稳定性,放电比容量高达163.1 mAh/g。在充电过程中,SN上具有孤电子对的氰基与高活性过渡金属离子配位络合,可减少电解质/电极界面副反应,提高正极材料的结构稳定性。     

Synthesis and characterization of YAG:Ce³⁺ fluorescence powders by co-precipitation method

YAG:Ce3+(Yttrium aluminum garnet) fluorescence powders were successfully prepared by co-precipitation method using aluminum nitrate,yttrium nitrate,cerous nitrate as the starting materials and ammonium carbonate as precipitant.The products were characterized by X-ray powder diffraction,luminescence spectrometer,transmission electron microscope(TEM).The XRD results showed that the obtained YAG:Ce3+ fluorescence powders had the crystalline structures of YAG at calcinations temperature of 900 oC and the TEM results showed that the grain diameters were about 100 nm.The YAG:Ce3+ fluorescence powders,synthesized by co-precipitation method,had the best luminescence property when the Ce doping amount was x=0.06 in the molecular formula of Y3-xCexAl5O12,the calcinations time was 2 h and the calcinations temperature was 1000 °C.     

固态氧化物熔盐电解的研究进展

本文介绍了熔盐电解固态氧化物技术在稀有难熔金属制备方面的应用,结合Ti的制备分析了FFC法的发展、工艺特点以及所面临的问题,重点阐述了导电性对FFC法生产的影响。以太阳能级硅(SOG-Si)的制备和多孔膜有效应用为例介绍了熔盐电解固态氧化物技术应用的最新研究进展。综合熔盐电解固态氧化物技术的研究现状,提出室温离子液体中电脱氧制备金属及合金,是实现冶金过程绿色生产的新方法,电解固态氧化物技术的应用有着很好的工业化前景,但要实现大规模工业生产仍然面临着诸多问题。     

溶液燃烧-钙还原法合成锆锰铁合金微粉

以锆、锰、铁的硝酸盐和甘氨酸为原料,采用溶液燃烧法制得超细金属氧化物前驱体,再将前驱体分别在750、850和950℃由氢化钙还原得到锆锰铁三元合金微粉.用热重/差热分析法(TG/DTA)、X射线衍射(XRD)、扫描电镜(SEM)等对溶液燃烧和钙还原2个阶段的产物进行分析与表征.结果表明:采用溶液燃烧法合成的金属氧化物前驱体颗粒分布均匀,粒度为数百纳米;采用氢化钙还原氧化物前驱体,在温度≥850℃,Ar气氛下反应1h可制得ZrMnFe三元单相合金微粉,粒度为亚微米或微米级.     

花状Co–Ni氢氧化物电极材料的制备与电化学特性

采用原位生长法, 以硝酸钴和氨水为原料、硝酸铵为生长剂, 制备生长在泡沫镍上的Co (OH)₂电极材料, 并在此基础上对其进行镍添加改性, 旨在得到比电容高、循环性能好的Co–Ni氢氧化物电极材料。通过X射线衍射仪、扫描电子显微镜对Co–Ni氢氧化物电极材料进行物相和微观形貌分析; 通过循环伏安、恒流充放电和交流阻抗等方法对Co–Ni氢氧化物电极材料的电化学性能进行分析和表征。结果表明: 镍添加使材料从原有的Co (OH) ₂晶相变为Co (OH) ₂和Ni (OH) ₂双晶相材料, 使原有的簇状结构转变为更利于离子扩散的花状结构, 进而促进材料电化学性能的提高。当Co/Ni摩尔比为3:1时制得的花状Co–Ni氢氧化物电极材料的电化学性能最好, 在5 m V·s-1扫速下的比电容值为3674.7 F·g-1, 在5 A·g-1电流密度下的比电容值为1450.0 F·g-1, 在20 A·g-1电流密度下循环5000次的比电容保持率为77.1%。     

Effect of sintering temperature on morphology and arc erosion properties of La-Ni-O ceramic and its composites

Ceramic LaNiO3 samples were prepared by solid state reaction method at different sintering temperatures. It was found that the resultant was not ABO3 perovskite single phase but dual phase La2NiO4 and NiO, and the percentage of the two phases varied with sintering temperature. Ceramics sintered at 1400 ℃ were well crystallized and the phase ratio of La2NiO4 was the maximum. The surface morphology observed by scanning electron microscopy (SEM) indicated that the grains of the ceramics sintered at 1400 ℃ were uniform and compact, which were in agreement with the properties of high density and low electrical resistivity of the samples. X-ray diffraction (XRD) patterns of ceramics before and after arc erosion indicated their high structural stability, which resulted in the good arc erosion resistance properties for silver-based electrical contact materials. The contact materials prepared with the ceramic sintered at 1400 ℃ exhibited better mass transition and arc erosion resisting properties.     

氧化钨/碳纳米管膜复合负极的制备及其储锂性能

氧化钨(WO₃)因具有较高的理论比容量(693 mAh/g)已成为锂离子电池负极材料的有力候选者。但在电池充放电即锂离子脱/嵌入过程中WO₃会产生较大的体积变化,导致其放电比容量快速衰减,故对其循环稳定性研究仍是热点之一。文中采用水热法和喷涂法分别在碳纳米管膜(CMF)基底上成功合成了水热型-氧化钨/碳纳米管膜(H-WO₃/CMF)和喷涂型-氧化钨/碳纳米管膜(S-WO₃/CMF)复合电极。XRD测试结果显示H-WO₃/CMF和S-WO₃/CMF中的WO₃分别属于单斜相和六方相。将H-WO₃/CMF和S-WO₃/CMF分别组装成扣式电池进行电化学性能测试,结果表明H-WO₃/CMF的首次放电比容量高于S-WO₃/CMF。当H-WO₃/CMF以0.2 C倍率循环时,第1圈放电比容量达到635 mAh/g,循环50圈时放电比容量为510 mAh/g,仍有上升趋势; S-WO₃/CMF在0.2 C倍率下循环时,第1圈放电比容量仅为515 mAh/g,在后续循环过程中容量衰减较快。交流阻抗测试结果显示H-WO₃/CMF的导电性高于S-WO₃/CMF。研究结果表明:H-WO₃/CMF作为锂离子电池负极,有望提升WO₃的电化学稳定性。      

Field Evaluation of a Proprietary Storm-Water Treatment System: Removal Efficiency and Relationships to Peak Flow, Season, and Dry Time

A proprietary storm-water treatment system (Baysaver 1/2?K) was monitored as part of a low impact development project to assess pollutant removal efficiency and to model removal as a function of flow rate, season, and dry time. Twenty six storm events were sampled over a 12-month period and analyzed for total suspended solids, turbidity, conductivity, ammonia/ammonium, nitrate/nitrite, total phosphorus, total Zn, total Pb, and total Cu. The data were analyzed to determine which parameters showed significant removal by the device and whether or not the removal efficiencies were influenced by peak flow rate, season of the year, and/or dry time. Results indicated that the removal of each pollutant analyzed was statistically significant with the exception of conductivity, which showed higher outflow levels resulting in significant release of ions. Regression analyses revealed that all pollutants except for conductivity and total phosphorus showed significant negative relationships to peak flow rate and that conductivity and total Cu reductions were significantly related to the season of the year.     

自蔓延法制备Ca_(2.95)Sm_(0.05)Co_(3.995-x)Ni_(0.005)Fe_xO_(9+δ)及其热电性能的研究

以柠檬酸为螯合剂,硝酸盐和氧化物为原料,通过自蔓延法合成了Ca_(2.95)Sm_(0.05)Co_(3.995-x)Ni_(0.005)Fe_xO_(9+δ)(x=0、0.10、0.15、0.20)陶瓷粉体材料,并对Ca_(2.95)Sm_(0.05)Co_(3.995-x)Ni_(0.005)Fe_xO_(9+δ)(x=0.10)粉体进行了压制实验;在473~973 K温度范围内,探索了Ca_(2.95)Sm_(0.05)Co_(3.995-x)Ni_(0.005)Fe_xO_(9+δ)的热电性能。结果表明:Ca_(2.95)Sm_(0.05)Co_(3.995-x)Ni_(0.005)Fe_xO_(9+δ)陶瓷粉体的压制规律符合黄培云压制方程,压制模量M为1.86 MPa,非线性指数m为2.074;材料的电导率和Seebeck系数随温度的升高而升高;热导率随温度的升高而降低;在973 K时,Ca_(2.95)Sm_(0.05)Co_(3.995-x)Ni_(0.005)Fe_xO_(9+δ)的ZT值达到0.13。Ca_(2.95)Sm_(0.05)Co_(3.995-x)Ni_(0.005)Fe_xO_(9+δ)是具有潜在应用前景的热电材料。     

偏钒酸钾-硝酸铊纳米复合粉体的制备及其光催化降解苏丹红Ⅱ号的研究

采用硝酸铊、偏钒酸钾、亚硫酸钠、二氧化锰为反应原料,经过水热法合成出了偏钒酸钾-硝酸铊纳米复合粉体,活化该复合粉体后考察其对苏丹红Ⅱ号的降解能力,并对粉体进行SEM、XRD、XPS表征。实验结果表明,偏钒酸钾掺杂量为2.5%(质量分数)的复合粉体具有最强的催化活性,25 mg的偏钒酸钾-硝酸铊纳米复合粉体可对200 m L浓度为1×10~(-3)mol/L的苏丹红溶液有效降解。     

钠源对正极材料Na3V2（PO4）3性能的影响

采用溶胶凝胶-高温固相法,用不同的钠源制备NASICON结构钠离子电池正极材料Na₃V₂（PO₄）₃.借助扫描电子显微镜（SEM）,X射线衍射分析（XRD）,电池测试系统及电化学工作站对制备的Na₃V₂（PO₄）₃结构,形貌,电性能和内阻进行表征.研究结果表明,以Na₂CO₃为钠源合成Na₃V₂（PO₄）₃有更好的颗粒尺寸,形貌结构完整,充放电性能及循环稳定性更好,阻抗也较小;在2.5~4.0 V电压范围内,以0.2 C进行充放电,首次放电比容量达到110.8 mAh/g,50次循环后容量保持率为85.1 %.      

Synthesis of lanthanum ricinoleate and its effect on thermal stability and mechanical properties in PVC

The lanthanum ricinoleate（abbreviated as Lari3） of rare earth heat stabilizer was synthesized by the reaction of ricinoleic acid, lanthanum nitrate and sodium hydroxide. The IR and fluorescence spectra methods confirmed the structure of the product. The thermal stability of PVC in the presence of Lari3 was studied by the Congo method and using TG analysis. The results showed that Lari3 could be used as a thermal stabilizer for PVC. When the ratio of Lari3/pentaerythritol was 3：1, the complex exhibited better synergistic effect. Incorporation of Lari3 to PVC resulted in a marked increase of maximum and onset degradation temperature as well as elongation and impact strength of PVC. Lari3 might replace the labile chlorine atoms to interrupt the formation of conjugated double bonds in PVC chains and act as HCl scavenger to restrain the self-catalyticdehydrochlorination.     

Hydrogen-Based Nitrate and Selenate Bioreductions in Flue-Gas Desulfurization Brine

The H2-based membrane biofilm reactor (MBfR) was shown to simultaneously reduce nitrate and selenate in flue-gas desulfurization (FGD) brines (15–33 g/L TDS). The MBfR also used polyester fibers, which differ from the composite gas-transfer fibers used in previous MBfR studies. Selenate reduction was nearly 100% in all media tested and was immediate, which suggests that selenate was coreduced with nitrate, possibly by the same microorganisms. A step increase in the nitrate removal flux was observed at a H2 pressure greater than 20 psig (138 kPa) using polyester fibers. High concentrations of nitrate and sulfate had no inhibitory effect on selenate reduction as long as H2 was available. In comparison with previous MBfR experiments treating ion-exchange brine, total electron equivalent fluxes were 29% lower and in contrast to earlier work on selenate reduction in fresh water, sulfate reduction was inhibited, likely due to the high total dissolved solids in the FGD brine or insufficient H2 availability due to CaCO3 or Se° precipitation onto the tighter polyester fibers.     

羟基氧化镍的制备及电化学性能研究

采用液相化学氧化法研究了β相羟基氧化镍的制备条件,并对产物形貌和电化学性能进行了分析。通过正交试验和单因素试验,得出反应的最佳制备条件。以XRD和SEM测试手段,对样品的晶体结构和形貌进行了研究。XRD分析表明,合成的样品为六方晶系的β-Ni OOH。SEM分析表明,制取的β-Ni OOH晶体形状为球形。通过恒流放电和循环伏安测试表明,样品具有良好的初始放电性能和电化学可逆性,适合于作镍锌电池的正极材料。     

Synthesis and characterization of YAG: Ce3+ fluorescence powders by co-precipitation method

YAG:Ce³⁺(Yttrium aluminum garnet) fluorescence powders were successfully prepared by co-precipitation method using aluminum nitrate, yttrium nitrate, cerous nitrate as the starting materials and ammonium carbonate as precipitant. The products were characterized by X-ray powder diffraction, luminescence spectrometer, transmission electron microscope (TEM). The XRD results showed that the obtained YAG:Ce³⁺ fluorescence powders had the crystalline structures of YAG at calcinations temperature of 900 °C and the TEM results showed that the grain diameters were about 100 nm. The YAG:Ce³⁺ fluorescence powders, synthesized by co-precipitation method, had the best luminescence property when the Ce doping amount was x=0.06 in the molecular formula of Y_3-xCe_xAl₅O₁₂, the calcinations time was 2 h and the calcinations temperature was 1000 °C.