微波辐照下PbS和PbO的升温速率及其反应动力学

研究了PbS和PbO在微波辐照下的升温速率及其反应动力学.结果表明,微波辐照下PbS和PbO的交互反应系一非恒温过程且动力学方程为lnα=ln[Am/(E aR)-(E aR)]/(RT)微波辐照下PbS与PbO的交互反应与传统方式加热下的相比较,其活化能降低,化学反应速度加快.     

KINETICS OF REACTION BETWEEN PbS AND PbO

The rate equation of reaction between PbS and PbO is dα/dt=kx_(PbS)~3 x_(PbO)~(-2).A transition product,PbSO_4·2PbO,is found by X-ray diffraction analysis.The reaction mechanism was dis-cussed on the basis of electron transfer.     

KINETICS OF INTERACTION OF PbO, xPbO·SiO_2 WITH PbS AND ACTIVITY OF PbO

<正> 为了阐明QSL法直接炼Pb的化学反应动力学,研究PbS与PbO及xPbO·SiO_2的交互作用是具有实际意义的。为了避免高温造成PbS和PbO的挥发损失,在较低温度下研究该体系的交互反应动力学,对探索火法炼Pb新工艺具有一定价值。 试料是分析纯PbO,PbS和合成的纯xPbO·SiO_2,试料粒度均为100—120 mesh,在配比试样中以PbO:PbS=2:1作基础并混匀,以便保证按化学计量反应产生SO_2。装有试料的刚玉坩埚在密封竖直刚玉管底部低温区用Ar气保护升温加热,待达到预期温度后,坩埚由密封系统中的活动撑杆推到高温区并同时用Ar气载流使产生的SO_2连续为碘量法所测     

PbS与PbO及硅酸铅反应的动力学和PbO的活度

为了阐明QSL法直接炼Pb的化学反应动力学,研究PbS与PbO及xPbO·SiO_2的交互作用是具有实际意义的。为了避免高温造成PbS和PbO的挥发损失,在较低温度下研究该体系的交互反应动力学,对探索火法炼Pb新工艺具有一定价值。试料是分析纯PbO,PbS和合成的纯xPbO·SiO_2,试料粒度均为100—120 mesh,在配比试样中以PbO:PbS=2:1作基础并混匀,以便保证按化学计量反应产生SO_2。装有试料的刚玉坩埚在密封竖直刚玉管底部低温区用Ar气保护升温加热,待达到预期温度后,坩埚由密封系统中的活动撑杆推到高温区并同时用Ar气载流使产生的SO_2连续为碘量法所测     

PbS和PbO·SiO_2交互反应动力学SCIEI

本文研究了T=900—1100℃时,PbS和PbO·SiO_2的交互反应。得出函数F(α)=(0.5-α)/((1-α)^(5/3))与t的直线关系。认为反应前期是化学控制,反应后期是扩散控制,计算出化学反应活化能ΔE=140kJ/mol,扩散活化能ΔE_D=105.8kJ/mol。     

THE RATE OF TEMPERATURE INCREASE AND THE KINETICS OF PbS AND PbO IRRADIATED WITH MICROWAVE

The rate of temperature increase and the kinetics of PbS and PbO, irradiated with microwaves, have been studied. According to the experimental data, the interaction between PbS and PbO is nonisothermal, and the activation energy becomes lower and the rate of interaction becomes faster with microwave irradiation than with conventional heating.     

硫磺共磨对铜铅锌氧化物表面性质和浮选的影响（英文）

研究3种有色金属氧化物(CuO,PbO和ZnO)与单质硫璜在轻度干磨条件下的反应,并对磨后产物进行浮选实验,以期探索磨后产物的表面性质及可浮性的变化。考察磨后产物的相变、形貌特征、电化学性质及表面化学组成等。结果表明,通过Cu—S键合,在颗粒表面形成了具有类CuS性质的薄层,在与单质硫璜干磨后,CuO的可浮性明显提升。机械化学硫化处理后,PbO的可浮行下降,主要因为颗粒表面的碳酸盐化以及PbO与S之间发生生成PbS和PbSO_4的歧化反应。机械化学硫化对ZnO的作用不大。     

电动势法测量Na_2PbO_2和Na_2ZnO_2生成自由能

以PbO、ZnO和NaOH为原料,通过固相反应法制备出Na2PbO2和Na2ZnO2,并利用XRD对Na2PbO2和Na2ZnO2进行表征。采用β(β″)-Al2O3固体电解质管构建Pt∣PbO,Na2PbO2‖β(β″)-Al2O3‖NaCrO2,Cr2O3∣Pt和Pt∣ZnO,Na2ZnO2‖β(β″)-Al2O3‖NaCrO2,Cr2O3∣Pt电池,通过测量电池反应电动势,计算出Na2PbO2和Na2ZnO2的生成自由能,并得到其生成自由能与温度(700~1273K)的关系式。     

多元异质结CdS/PbS/TiO2的制备及其对304不锈钢光生阴极保护性能研究

采用阳极氧化法制备TiO₂纳米管,通过超声辅助连续离子沉淀法对TiO₂纳米管进行CdS/PbS共复合修饰改性。应用X射线衍射 (XRD)、扫描电镜 (SEM) 及其配套的能谱分析 (EDS) 对CdS/PbS/TiO₂的晶型特征、表面形貌及元素分布进行表征;利用电化学分析方法研究了复合次序对CdS/PbS/TiO₂的光电性能影响,考察了CdS/PbS/TiO₂复合材料对304不锈钢的阴极保护性能。结果表明:成功制备了晶型特征和表面形貌良好的CdS/PbS/TiO₂多元异质结;先复合9次PbS、再复合15次CdS的TiO₂纳米管具有更加优良的光电性能;光照下CdS/PbS/TiO₂复合材料对304不锈钢光生阴极保护性能显著优于单一PbS复合的TiO₂和纯TiO₂;在暗态下CdS/PbS/TiO₂复合材料储能效果良好,可延长对304不锈钢的阴极保护作用。     

界面耦合的PbSO4溶解和PbS沉淀及其对铅矾硫化浮选的影响(英文)

通过浮选试验、X射线光电子能谱(XPS)、场发射扫描电子显微镜(FESEM)、拉曼光谱和紫外-可见漫反射光谱(UV-Vis DRS)系统研究铅矾浮选中的硫化机理。浮选试验证明硫化钠对铅矾浮选具有活化作用；但必须控制硫化钠浓度，以避免过量硫离子对浮选的抑制。XPS、拉曼光谱和UV-Vis DRS结果表明，用硫化钠水溶液处理铅矾时，PbSO₄被PbS取代。FESEM观察结果显示硫化过程中PbSO₄的溶解和PbS纳米粒子的沉淀。因此，可认为铅矾与硫化钠水溶液的反应是通过界面耦合溶解–沉淀机制进行的：在与硫化钠水溶液接触时，铅矾溶解将Pb²⁺和SO₄^2–释放到流体边界层中，该流体边界层相对于PbS相变得过饱和；然后，PbS纳米粒子在铅矾表面成核并生长。生长在铅矾表面的PbS纳米颗粒可以提高铅矾的可浮性。     

离子液体对PbO2电极性能的影响

目的 提升PbO2电极寿命以及对酚类废水的电氧化催化活性和选择性。方法 分别添加离子液体1-丁基-3-甲基-咪唑六氟磷酸盐（[BMIM]PF6）和1-乙基-3-甲基-咪唑四氟硼酸盐（[Emim]BF4）至Pb(NO3)2溶液中,用阳极电积法制备了有SnO2+Sb2O3中间层的PbO2电极。通过扫描电镜（SEM）、X射线衍射仪（XRD）、加速寿命实验、线性扫描和循环伏安测试、电氧化降解实验等考察了不同离子液体的电离产物对电极性能的影响,并与采用F-修饰的常规PbO2电极的性能进行了对比。结果 离子液体修饰的PbO2电极晶粒结晶度高,晶面取向发生改变,晶粒大小均一度高,表面平整致密、棱角多,电极有效表面积和活性点增多,且[BMIM]PF6修饰的PbO2优于[Emim]BF4修饰的PbO2。[BMIM]PF6修饰的PbO2和F-修饰的PbO2的加速寿命和电极性能稳定期分别为168.8、162.6 h和101.2、69.8 h,析氧电位分别为1.71 V和1.59 V。循环伏安显示,[BMIM]PF6修饰PbO2氧化峰电位更小,氧化峰电流更大,相同条件下,[BMIM]PF6和F-修饰PbO2对p-NP废水的电氧化降解率和有机碳去除率分别为95.7%、87.1%和85.2%、61.5%,而电解槽槽压分别为3.26 V和3.47 V。结论 离子液体[BMIM]PF6、[Emim]BF4修饰PbO2电极的结晶度、晶粒均一性、致密性增强,电极活性点增多,且由于两种离子液体电离的离子大小不同,导致对电沉积晶粒的空间位阻不同,使得前者强于后者。晶粒形态和组织结构的差异,使得[BMIM]PF6修饰PbO2对酚类废水的电氧化催化活性、选择性和寿命显著增强。     

Electrical and optical characteristics of Au/PbS/n-6H-SiC structures prepared by electrodeposition of PbS thin film on n-type 6H-SiC substrate

To realize Schottky barrier height (SBH) modification in the Au/n-6H-SiC Schottky diodes, lead sulfide (PbS) thin films were grown on n-6H-SiC by electrodeposition method. At first, XRD experiments were performed to investigate the crystal structure of the PbS film electrodeposited on n-6H-SiC. It has been deduced from the diffraction profile that the PbS thin film has a crystal structure more strongly oriented along the [2 0 0] direction. An optical energy band gap value of 1.42 eV for the PbS film was obtained from its optical absorption spectra. Then, we have prepared Au/PbS/n-6H-SiC Schottky barrier diodes (SBDs) with interface layer and reference Au/n-6H-SiC/Ni SBDs. The SBH enhancement has been succeeded by the PbS interlayer, influencing the space charge region of the SiC. The SBH values of 1.03 and 0.97 eV for the samples with and without the interfacial PbS layer were obtained from the forward bias current-voltage (I-V) characteristics. The SBH increase in the Au/PbS/n-6H-SiC SBD with the interfacial PbS layer has been attributed to the fact that the interface states contain a net negative interface charge in metal/n-type semiconductor contact due to the presence of the interfacial PbS layer.     

Broadband near-infrared luminescence and tunable optical amplification around 1.55 μm and 1.33 μm of PbS quantum dots in glasses

Silicate glasses containing PbS quantum dots (QDs) with narrow size distribution were prepared through heat treatment. Transmission electron microscopy (TEM) results show that spherical PbS QDs are densely dispersed in the glassy matrix. Using ZnS-PbO to replace PbS as precursor of PbS QDs, the size distribution of PbS QDs in glasses becomes more uniform. Tunable infrared luminescence from 1100 to 2200 nm has been obtained by controlling the glassy matrix and preparation parameters. Obvious optical amplification at communication windows of 1.55 μm and 1.33 μm is probed, and the PbS QDs doped glasses using ZnS-PbO as precursor exhibit larger optical amplification. The PbS QDs doped glasses with intense optical amplification are considered to be promising candidate as gain medium for broadband fiber amplifier and tunable fiber laser.     

Electrochemical characterization of PbS quantum dots capped with oleic acid and PbS thin films — a comparative study

This research aims at probing electrochemical response of oleic acid capped PbS quantum dots deposited on a Pt electrode in 0.1 M aqueous sodium hydroxide solution by cyclic voltammetry and chronoamperometry. Quantum dots were also characterized by photoluminescence and IR spectroscopy. Cyclic voltammetry of bulk PbS thin films obtained via chemical bath deposition is investigated in order to interpret the data on PbS quantum dots. It was found that the two materials exhibit essentially similar voltammetric behavior; however, oxidation of PbS quantum dots tends to start at slightly more cathodic potentials than that of bulk PbS films. This effect is attributed to the influence of capping oleic acid that binds lead ions into an insoluble lead oleate thereby causing the cathodic shift of the formal redox potential. The procedures designed to partially remove oleic acid from PbS quantum dots result in the anodic shift of the PbS quantum dots oxidation towards the values characteristic for the bulk material. A possibility of determining absolute positions of conduction and valence bands in quantum dots by cyclic voltammetry is discussed but the influence of the energy level structure of PbS quantum dots on their voltammetric response was not revealed under the conditions of the present study. However, PbS quantum dots can withstand multiple redox cycles whereas bulk PbS films dissolve readily upon the first oxidation. The effect was attributed to the oleic acid layers on the PbS quantum dots surface, those layers preventing soluble oxidation products from diffusing into the bulk of solution. Certain PbS quantum dots samples showed remarkable stability against oxidation typical for PbS and starting at ?0.2 V vs Ag/AgCl (sat.) and a stable response at oxidation and reduction at higher (0.55 V) and lower (?0.8 V) potentials, respectively.     

EFFECTS OF Pb COMPOUND ADDITIVES ON THE PROPERTIES OF YBa2Cu3O7-δ

The melting temperature and critical transition temperature T, of YBa2Cu3O7-δ with deferent content additives of PbO and BaPbO3 were studied. When PbO was doped in YBa2Cu3O7-δ the melting temperature of YBa2Cu3O7-δ was reduced, however its superconductivity was weakened. From the XRD pattern of the sintered mixture of YBa2Cu3O7-δ and PbO, it was known that there was a reaction between YBa2Cu3O7-δ and PbO, and the product was BaPbO Hence different contents of BaPbO3 (10mass%, 20mass% and 30mass% ) were added in YBa2Cu3O7-δ It was proved that there were no reactions between YBa2Cu3O7-δ and BaPbO3.And the superconductivity of the mixtures was much better than that of the samples with PbO additive.     

EFFECTS OF Pb COMPOUND ADDITIVES ON THE PROPERTIES OF YBa2Cu3O7-δ

The melting temperature and critical transition temperature Tc of YBa2Cu3O7-δ with deferent content additives of PbO and BaPbO3 were studied. When PbO was doped in YBa2Cu3O7-δ the melting temperature of YBa2Cu3O7-δ was reduced, however its superconductivity was weakened. From the XRD pattern of the sintered mixture of YBa2Cu3O7-δ and PbO, it was known that there was a reaction between YBa2Cu3O7-δ and PbO, and the product was BaPbO3. Hence different contents of BaPbO3 ( 10mass%, 20mass% and 30mass% ) were added in YBa2Cu3O7-δ. It was proved that there were no reactions between YBa2Cu3O7-δ and BaPbO3. And the superconductivity of the mixtures was much better than that of the samples with PbO additive.     

Surface Analysis of Ti/Sb-SnO2/PbO2 Electrode after Long Time Electrolysis

主要考察Ti/Sb-SnO2/PbO2电极在Na2SO4溶液中恒电流密度长时间电解后,其电极表面状态的变化情况。通过扫描电镜与元素分析来考察电极表面形貌变化及表面元素分布情况,通过X射线衍射来考察电极表面氧化物的晶型变化情况,通过电感耦合等离子体仪来检测电解液中金属元素的浓度变化。结果表明,在长时间电解后,PbO2电极表面存在氧化物层溶蚀与脱落区域。在电解完成后的电解液中检测到Pb元素,表明电极表面存在Pb元素的溶解。X射线衍射表明电极表面仍然为PbO2层,只是相应的衍射峰强度有所降低。由上述结果推测PbO2电极失效的可能原因是：表层氧化物溶解、脱落以及基体的钝化。