水解法制备纳米二氧化钛

以工业TiOSO4为原料,采用水解法制备了纳米二氧化钛粉体,并用XHD、SEM、激光粒径分析仪对其形貌、晶型、粒径分布进行了表征。试验表明：晶种的质量对于诱导TiOSO4水解成核和控制偏钛酸的原生粒子大小有较大影响;在偏钛酸粒子沉淀中加入不同的促进剂,煅烧后．可以得到锐钛型和金红石型的二氧化钛粉体,以满足市场的不同需求。     

水热法制备氧化锌纳米棒阵列的生长动力学研究

采用低温水热方法,在经预先修饰的基底上制备出取向高度一致的ZnO纳米棒阵列.用SEM和XRD等手段对制备的纳米棒阵列进行了表征.ZnO纳米棒阵列水热生长动力学表明:当生长时间在8h内时,纳米棒的生长速度较快,之后纳米棒的生长近乎停止,棒的长度和直径基本不再改变.在生长速度较快的8h内时,纳米棒的径向生长由两个明显的动力学过程组成,即由生长时间在1.5h内的快速生长步骤和随后的慢速生长步骤组成;纳米棒的长度以约5.5nm·min^-1的生长速度增加至2.4μm.     

水热法制备WO3纳米棒阵列及其光催化性能

采用水热法,以Na₂WO₄·2H₂O为原料,NaCl为添加剂,直接在氧化铟锡透明导电基底上制备了有序WO₃纳米棒阵列.利用X射线衍射、扫描电子显微镜、透射电子显微镜和高分辨透射电子显微镜等手段对制备的纳米棒进行了表征,考察了pH值对产物形貌、尺寸和取向性的影响.结果表明：单根WO₃纳米棒具有六方单晶结构,随着前驱液pH值的增大,平行于基底生长的WO₃纳米棒捆逐渐转变为垂直于基底生长的纳米棒阵列.另外,对制备得到的两种不同取向的WO₃纳米棒结构进行了光催化降解甲基蓝溶液的研究,发现相比于WO₃纳米棒捆结构,纳米棒阵列的光催化性能更高.     

以偏钛酸（硫酸钛,硫酸氧钛）为原料制备纳米二氧化钛

1前言纳米TiO2又称超微细TiO2或透明超微TiO2，是80年代后期TiO2领域的一个新产品，其粒径小于100nm，仅为普通TiO2的1／10左右．由于颗粒尺寸的细微化，导致纳米TiO2具有表面效应、体积效应和久保效应，使其在很多方面表现出独特的性能，成为一种高功能化的新型精细无机材料和     

钒酸钴纳米片的析氧性能研究

析氧反应(OER)是电解水制氢过程中的决速步,因此构建高效、低成本的非贵金属基OER电催化剂是实现氢能源高效制取的关键。通过两步水热法将Co元素引入到V₂O₅中,从而制备出了钒酸钴(Co₃V₂O₈)纳米片结构,Co元素的引入使纳米片暴露更多的活性位点,并提高导电性加快了电荷传输,因而可提高其 OER性能。形貌和成分表征结果显示所制备的催化剂为正交晶系的 Co₃V₂O₈纳米片结构。对该催化剂进行系统的 OER 性能研究,结果表明,Co₃V₂O₈催化剂产生 10 mA·cm^-2的析氧电流密度需要 364 mV的过电位,产生 100 mA·cm^-2的析氧电流需要过电位仅为 540 mV,对应的 Tafel斜率为 62 mV·dec^-1,此外,在经历 1000次循环测试后,该催化剂极化曲线不...     

PEM水电解用多层钛网析氧阳极制备及性能研究

以钛网为扩散层基体,氯铱酸为前驱体,采用浸渍-热解法制备了IrO₂/Ti 析氧阳极,进一步采用热压法制备膜电极.综合扫描电镜尧循环伏安尧交流阻抗尧单池性能曲线测试及阳极寿命强化测试,研究了不同层数钛网析氧阳极对性能及寿命的影响.结果表明院与单层钛网析氧阳极比较,采用双层钛网析氧阳极,积分电荷由84.27 mC/cm2 增至153.12 mC/cm2,电极电化学反应阻抗由7.38 Ω·cm2 降低至3.03 Ω·cm2,单池性能得到提升.寿命强化测试表明,采用双层钛网析氧阳极在稳定性及寿命方面有显著提升,稳定运行时间由30 h 增加到了53 h.      

以氧传感器为基的辅助电极型冶金传感器的研究进展

金属熔体的化学组成是金属冶炼过程的重要参数,固体电解质传感器可以提供金属冶炼过程中成分变化的实时信息;这些信息可以提高生产效率,提升产品质量.由于缺乏以待测元素为导电离子的固体电解质,除氧以外的一些元素的测量多通过在电解质的表面涂覆一层含待测元素和电解质中导电离子元素复合物的方法来实现.总结了氧传感器及其他元素成分传感器的研究进展,介绍了以氧传感器为基础的辅助电极型成分传感器,并对辅助电极型传感器的应用和发展进行了展望.     

以偏钛酸为原料在室温离子液体中水热制备二氧化钛光催化剂

以偏钛酸作原料,用1-烯丙基,3-甲基咪唑氯([AMIM][Cl])室温离子液体,在温度160℃下水热制备了锐钛矿型的纳米二氧化钛.借助于X射线衍射仪(XRD),透射电子显微镜(TEM),和紫外.可见分光光度计(UV-Vis)等手段分别对所制备光催化剂的晶型、形貌、光学特性和光催化性能进行了表征.结果表明:所制备的二氧化钛光催化剂为锐钛矿型,其平均晶粒大小为18.4nm,颗粒为类椭球状,在可见光区存在一定的吸收,光催化性能测试表明所制备光催化剂降解亚甲基蓝的能力高于商业品P.25,并且在可见光照射下表现出了一定的光催化活性.     

氮掺杂碳纳米纤维网/炭纸有序化气体扩散电极的制备及其氧还原性能

以自制炭纸为基体,在其表面电化学合成聚苯胺纳米纤维网涂层,经过热处理后得到氮掺杂碳纳米纤维网/炭纸有序化气体扩散电极。采用扫描电镜(SEM)、透射电镜(TEM)、傅立叶变换红外光谱(FTIR)和X射线光电子能谱(XPS)表征材料的形貌与结构特征,采用循环伏安法、线性扫描伏安法和交流阻抗谱研究材料的氧还原催化性能。结果表明,当n(苯胺单体)/n(盐酸)为0.4时,得到均匀、连续的网状聚苯胺纳米纤维网涂层,其结构在热处理后得到有效保留。与传统涂覆法制备的氮掺杂碳纤维/炭纸复合电极相比,有序化电极的氧还原性能更佳,欧姆阻抗和扩散阻抗更小。在O_2饱和的浓度为0.1 mol/L的KOH水溶液中,有序化电极的氧还原电流密度达到0.76 m A/cm~2,是传统电极的1.6倍。     

两步水热法制备纳米花状Ni3Fe/Ni3S2高效电催化剂促进碱性电解水析氧反应

分别以Fe(NO₃)₃·9H₂O和Na₂S·9H₂O作为Fe源和S源,用镍网(nickle mesh,NM)作为Ni源与支撑基底,采用两步水热法合成Ni₃Fe/Ni₃S₂析氧催化剂,通过X射线衍射、X射线光电子能谱、扫描电镜和透射电镜分析催化剂的显微组织与形貌,用电化学工作站进行电化学性能测试。结果表明：两步水热法合成的Ni₃Fe/Ni₃S₂催化剂为丰富立体的纳米花形貌,这种形貌可提升催化剂的空间利用率。Ni₃S₂暴露出高折射率的{210}晶面,与Ni₃Fe的(111)晶面产生协同效应,从而提升了催化活性。在1 mol/L的KOH溶液(25℃)中,10 m A/cm²电流密度下Ni₃Fe/Ni₃S₂     

Preparation of Ca- Fe oxygen carrier using metallurgical dust

Chemical chain combustion technology is a new combustion technology that achieves efficient and low energy separation for CO2 capture. CaSO4- Fe2O3 oxygen carrier was prepared by sol- gel method from blast furnace slag containing iron, and X- ray diffraction (XRD) and scanning electron microscopy and energy dispersive X- ray (SEM- EDX) were used to characterize the oxygen carrier particles. The results show that the CaSO4- Fe2O3 oxygen carrier prepared from iron metallurgical dust has a mass fraction of 93. 58%, a specific surface area of 10. 37cm2/g and a conversion rate of 67. 47% after reaction?? with coal powder, which has good reactivity. Combined with SEM and EDS analysis, the main cause of the decrease of carrier activity is the accumulation of coal ash during the cycle combustion process, resulting in complex and diversified carrier components, chemical reactions and agglomeration effects, and then carrier activity is reduced.     

Preparation of titanium metal by electrochemical reduction of titanium dioxide

Preparation of titanium metal by direct electrolytic reduction of TiO₂ in molten CaCl₂ bath was studied using sintered TiO₂ pellets as cathode. The process was carried out at 950°C under normal atmosphere without using any inert gas. Titanium was obtained in the form of powder/compact product depending on the method of preparation of the pellets and the reaction conditions. The product was characterized by XRD, SEM and EPMA. The purity of the product was >99% as evidenced from EPMA analysis.     

Synthesis gas production using oxygen storage materials as oxygen carrier over circulating fluidized bed

A novel process for synthesis gas production over Circulating Fluidized Bed （CFB） using oxygen storage materials as oxygen carder was reported. First, oxygen in the air was chemically fixed and converted to lattice oxygen of oxygen storage materials over regenerator, and then methane was selectively oxidized to synthesis gas with lattice oxygen of oxygen storage materials over riser reactor. The results from simulation reaction of CFB by sequential redox reaction on a fixed bed reactor using lanthanum-based perovskite LaFeO3 and La0.8Sr0.2Fe0.9CO0.1O3 oxides prepared by sol-gel, suggested that the depleted oxygen species could be regenerated, and methane could be oxidized to synthesis gas by lattice oxygen with high selectivity. The partial oxidation of methane to synthesis gas over CFB using lattice oxygen of the oxygen storage materials instead of gaseous oxygen should be possibly applicable.     

Li4Ti5O12作为锂离子电池负极材料电化学性能

采用固相法合成了锂钛复合氧化物Li₄Ti₅O₁₂研究了保温时间对其结构及电化学性能的影响.结果表明,保温时间为2,4h时样品的循环性能比较好,在80mA/g充放电下,30次循环后的比容量可高达159mAh/g.     

析氧型贵金属涂层钛阳极的研究进展

贵金属涂层钛阳极是近年来发展起来的具有广阔应用前景的新型阳极,尤其在以有色金属电解为代表的电化学体系中,展示出巨大的发展潜力.文章综述了国内外析氧环境中贵金属涂层钛阳极的研究和开发方面的重要工作和进展,其中重点阐述了IrO2-Ta2O5涂层不同方法的改性研究.评述了各制备方法的优势和不足.同时,简单介绍了贵金属涂层钛阳...     

Preparation and characterization of Ce1-x NixO2 as oxygen carrier for selective oxidation methane to syngas in absence of gaseous oxygen

A citric acid complex method was employed to prepare Ce/Ni mixed oxides with various Ce/Ni ratios useful for selective oxidation methane to syngas in the absence of gaseous oxygen, and the catalytic activity measurement was investigated in a fixed bed reactor at 800 °C. The prepared oxygen carriers were characterized by various characterization techniques such as TG-DSC, XRD and TPR. The results of TG-DSC indicated that the Ce_1-xNi_xO₂ precursor generated a stable phase after the heat-treatment at temperatures above 800 °C. The XRD characterization suggested that some Ce-Ni solid solution was formed when Ni²⁺ ions was incorporated into the lattice of CeO₂, and it led to the generation of O-vacancy which could improve the oxygen mobility in the lattice of oxygen carriers. It was found that Ce_0.8Ni_0.2O₂ gave the highest activity in the selective oxidation methane to syngas reaction, and the average methane conversion, CO and H₂ selectivity reached to 82.31%, 82.41% and 87.64%, respectively. The reason could be not only attributed to the fitting amount of NiO dispersed on the CeO₂ surface and bulk but also to actual lattice oxygen amount increased in oxygen carrier.     

钛箔表面二氧化钛纳米管的可控制备研究

采用电化学阳极氧化法在金属钛箔表面制得了二氧化钛纳米管,通过调整阳极氧化电压和时间,控制纳米管的管径及管壁尺寸,采用扫描电镜(SEM)观察了不同制备条件下得到TiO2纳米管阵列的微观形貌,考察了氧化电压及时间对纳米管TiO2纳米管阵列形貌的影响;利用热处理工艺调整二氧化钛纳米管的晶型,通过X射线衍射仪(XRD)对样品晶...     

Carbochlorination kinetics of titanium dioxide with carbon and carbon monoxide as reductant

Kinetic study of the chlorination of titanium dioxide (rutile and anatase) was carried out in a fixedbed reactor at temperature ranging from 800 °C to 1000 °C and normal pressure. In our experiment, titanium dioxide powder and gaseous chlorine with carbon or carbon monoxide as reductant were used. The products of the reaction are all in gaseous phase under the temperatures and pressure studied. With CO as reductant, reaction is of noncatalytic gas-solid nature and experimental data fit the shrinking core model. When using C as reductant, solid-solid reaction is involved. Reactivity is highly enhanced by solid carbon and it is concluded that an activated C-TiO₂-Cl complex contributes to the enhanced reactivity. A reaction model based on phase boundary control applies to the experimental data. Thermodynamic analysis supports the experimental observation.     

The photogenotoxicity of titanium dioxide particles

We employed a series of in vitro genotoxicity assays--a single cell gel (SCG) assay with mouse lymphoma L5178Y cells, a microbial mutation assay with Salmonella typhimurium, a mammalian cell mutation assay with L5178Y cells, and a chromosomal aberration assay with Chinese hamster CHL/IU cells--to evaluate the photogenotoxicity of titanium dioxide (TiO2) particles. Without UV/visible light irradiation, TiO2 particles exhibited no or weak genotoxicity. With irradiation, however, TiO2 particles exhibited significant genotoxicity in the SCG and chromosomal aberration assays. Therefore, we concluded that TiO2 particles are photogenotoxic.