量子点敏化太阳电池FTO/CoS/CuS对电极的制备与性能

摘要：本文采用恒电位电沉积方法在FTO导电玻璃表面依次沉积CoS和CuS,形成 FTO/CoS/CuS复合对电极用于量子点敏化太阳电池。确定了电沉积电位和电沉积时间,并研究了电沉积温度对电极形貌及电催化活性的影响。对电极的表面形貌和微观结构采用SEM和TEM方法进行表征;对电极的光反射性能采用紫外可见分光光度计进行测试;对电极的电化学性能通过测试交流阻抗、Tafel极化曲线以及J-V曲线进行表征。研究结果表明,FTO/CoS/CuS对电极与电解液界面处的电荷转移阻抗较低,具有更高的光反射率及电催化活性。与Au片、FTO/CoS和FTO/CuS对电极相比,光电转化效率分别提高了132.9%,46.6%,26.9%。     

Cu_2O/TNTs电极的制备及其光电催化还原CO_2合成甲醇研究

以钛阳极氧化制备的TiO_2纳米管(TNTs)阵列为载体,采用脉冲电沉积法将Cu_2O沉积到TNTs的管壁上,制备了Cu_2O/TNTs电极。采用扫描电镜(SEM)、透射电镜(TEM)以及X射线光电子能谱(XPS)对电极的形貌以及沉积物价态进行了表征。通过循环伏安、光电流-时间曲线测试,研究了沉积电位以及沉积电量对电极光电催化性能的影响。结果表明:脉冲电沉积的沉积物为Cu_2O纳米颗粒。制备的Cu_2O/TNTs电极光电活性及稳定性明显优于Cu_2O/Ti电极。电位-0.5 V(相对于饱和甘汞电极)下脉冲沉积60mC制备的电极对CO_2还原具有较高的光电催化活性。在装有100 m L 0.1 mol/L NaHCO_3溶液的自制密闭反应器中利用Cu_2O/TNTs电极光电催化还原CO_2,合成的产物主要为甲醇,还原5 h后甲醇含量达到6.05 mg/L。     

电沉积制备Pt-Ru合金电极

采用电沉积法制备Pt-Ru合金电极.研究了电解液中Pt和Ru的浓度对电极表面组成形貌和电催化活性的影响.实验表明,优化电解液中Ru的浓度,可使电极表面形成分布均匀的纳米级Pt-Ru合金,并表现出良好的电催化性能.采用环境扫描电子显微镜表征电极的表面形貌;采用能谱仪测定Pt-Ru电极的表面组成;采用循环伏安法测量Pt-Ru电极的电化学性能.     

配位负载法制备CoS2/AOCF复合材料及其电催化析氢性能

以硫酸钴、硫代硫酸钠、硫和偕胺肟化聚丙烯腈纤维(AOCF)为原料,采用配位负载法制备了CoS2/AOCF复合材料,采用SEM、XRD、TEM、XPS和BET对CoS2/AOCF进行物相分析和形貌表征,并对CoS2/AOCF复合材料的电催化析氢性能进行了测试.结果表明,AOCF链上—OH、—NH2与Co(Ⅱ)的配位作用极大地提高了活性组分CoS2的比表面积,改变了活性组分的晶体结构,增大了有效活性位点的数量.CoS2/AOCF在10 mA/cm2的电流密度下过电势为92 mV,Tafel斜率仅为43 mV/dec,具有良好的析氢稳定性,展现了优异的电化学性能.     

掺杂Fe-PbO2电极的制备及其对酚类废水降解性能研究

采用阳极恒电流电沉积技术制备不锈钢基PbO2电极及掺杂Fe-PbO2电极。采用XRD、SEM、EDS等方法对电极的物相结构、表面形貌、元素组成进行了表征和分析,对PbO2电极及掺杂Fe-PbO2电极电催化氧化酚类模拟废水的降解率进行研究,结果表明:掺杂Fe-PbO2电极表面形貌及衍射强度发生不同程度的改变,添加的Fe3+可能进入了表层内部,掺杂Fe-PbO2电极较普通的PbO2电极对酚类废水具有更好的电催化氧化降解性能。     

配位负载法制备CoS2/AOCF复合材料及电催化析氢性能

以硫酸钴、硫代硫酸钠、硫和偕胺肟化聚丙烯腈纤维(AOCF)为原料，采用配位负载法制备了CoS2/AOCF复合材料，通过设计偕胺肟化聚丙烯腈高分子链上的—OH和—NH2基团与Co(Ⅱ)配位作用，极大提高了活性组分CoS2的比表面积，改变了活性组分的晶体结构，增大了有效活性位点的数量。采用SEM、XRD、TEM、XPS和BET对CoS2/AOCF进行物相分析和形貌表征，并对CoS2/AOCF复合材料进行电催化析氢性能测试。结果表明：CoS2/AOCF在10 mA/cm2的电流密度下过电势为92 mV，Tafel斜率仅为43 mV/dec，具有良好的析氢稳定性，展现了优异的电化学性能。     

染料敏化太阳能电池低铂对电极的制备和性能

采用热分解法制备Pt/ITO电极用于染料敏化太阳能电池（DSSC）。研究了热分解法相关工艺参数,包括烧结条件、不同的黏合剂以及黏合剂用量等。采用扫描电镜（SEM）分析了所制备的Pt/ITO对电极的表面形貌,通过循环伏安法（CV）对其电化学性能进行了表征。结果表明,采用适量羧甲基纤维素钠作为黏合剂,经5次烧结铂载量达到0235 mg/cm2时,Pt/ITO电极即对I^-/I^-₃（I₂）电对的氧化还原过程表现出良好的电催化活性。单体DSSC测试研究表明,所制备的低铂对电极的光电转换效率已接近铂片对电极的水平。     

钛丝负载Pt/TiO2电极的制备及其电催化测定化学需氧量研究

采用阳极氧化的方法,在钛丝上制备TiO2纳米管阵列薄膜,用恒电流沉积的方法在TiO2纳米管表面沉积Pt纳米晶,制备了钛丝负载的Pt/TiO2电极.用SEM对电极的形貌进行了表征,纳米管长度在3.5～10 μm之间与氧化电压和氧化时间密切相关,Pt纳米晶均匀沉积在TiO2纳米管表面.用极化曲线、循环伏安曲线、电流-时间曲线对Pt/TiO2电极的电催化性能进行表征.当沉积电流密度大于1.0 mA/cm2时,制备的Pt/TiO2电极的电催化性能显著高于Pt电极.而且,在甲醛等五种有机物溶液中的电催化结果表明,净电流和理论COD之间表现出很好的线性相关性,说明钛丝负载的Pt/TiO2电极可用于电催化快速检测水体中的化学需氧量.     

聚苯胺对电极在染料敏化太阳能电池的应用

通过软模板在FTO(导电玻璃)上化学浴沉积球状纳米聚苯胺和粉末聚苯胺,将以上两种对电极与无模板化学浴沉积聚苯胺对电极进行对比,并通过场发射扫描电子显微镜(FESEM)测试手段对这三种电极的表观形貌进行表征,对所制备三种电极进行了CV、EIS、Tafel、IV等电化学性能测试。结果表明:三种电极的表观形貌分别为球状结构聚苯胺、平整致密聚苯胺、蠕虫状聚苯胺,其中蠕虫状聚苯胺对电极因粗糙的表面和相对较大的厚度而具有较大的表面积,因此其催化活性位点也较多。而球状聚苯胺对电极则是三种电极中最有序的,规整的表面形貌使电极的导电性增加,加之其球状而产生的较大的表面积而使其光电转换效率在三种电极中最高,光电转换效率达到7.11%。     

Ce-PbO2电极的制备及对苯磺酰胺的电催化降解

采用共沉积法制备了铈改性二氧化铅电极，利用扫描电子显微镜(SEM)、X-射线衍射仪(XRD)、能谱仪(EDS)对电极表面微观结构和形貌进行了表征，同时测试了电极的电化学性能和电催化性能。结果表明：Ce-PbO₂电极表面结构致密，平均晶粒尺寸为17.83 nm，析氧过电位1.62 V(vs. SCE)，强化寿命可达74 h。在苯磺酰胺初始浓度50 mg·L^-1，电流密度40 mA·cm^-2,pH为6的条件下降解120 min后苯磺酰胺模拟废水的去除率为97.68%，化学需氧量(COD)去除率为62.45%。在40 mA·cm^-2的条件下对实际磺胺类废水处理4 h,COD去除率可达75.36%。     

Wet Milling of Fe/Al/Al2O3 and Fe2O3/Al/Al2O3 Powder Mixtures

Wet milling of Al₂O₃-aluminide alloy (3A) precursor powders in acetone has been investigated by milling Fe/Al/Al₂O₃ and Fe₂O₃/Al/Al₂O₃ powder mixtures. The influence of the milling process on the physical and chemical properties of the milled powders has been studied. Particle refinement and homogenization were found not to play a dominant role, whereas plastic deformation of the metal particles leads to the formation of dislocations and a highly disarranged polycrystalline structure. Although no chemical reactions among the powder components in Fe₂O₃/Al/Al₂O₃ powder mixtures were observed, the formation of a nanocrystalline, ordered intermetallic FeAl phase in Fe/Al/Al₂O₃ powder mixtures caused by mechanical alloying was detected. Chemical reactions of Fe and Al particle surfaces with the atmosphere and the milling media lead to the formation of highly porous hydroxides on the particle surfaces. Hence the specific surface area of the powders increases, while the powder density decreases during milling. The fraction of Fe oxidized during milling was determined to be 0.13. The fraction of Al oxidized during milling strongly depends on the metal content of the powder mixture. It ranges between 0.4 and 0.8.     

Preparation and properties of poly(Nε,Nε-dicarboxymethyl-l-lysine)

A new ampholytic homopolypeptide, $\text{poly}\text{(N}{}^{\mathrm{\epsilon }}\text{,N}{}^{\mathrm{\epsilon }}\text{-}\text{dicarboxy-methyl-}\text{l}\text{-lysine}\text{)}$, which has one tertiary amino and two carboxyl groups in the side chain has been derived from a hydrochloride salt of poly(L-lysine). The polymer in aqueous solution seems to be in the coil form with locally extended structure (LES) at neutral pH. In both the acidic and alkaline regions, the molar ellipticity of the polymer changes as a result of change in net charge on the side chain. The conformational changes may be from the coil with LES to other coiled forms. 5–7 M NaClO₄ and 80% aqueous methanol induce the α-helix in the polymer at neutral pH. Divalent cations, Cu²⁺ and Ca²⁺, do not induce any remarkably ordered structures such as α-helix or β-structure in the polymer in aqueous solution at any pH. Ultraviolet absorption studies show an absorption peak of the polymer-Cu²⁺ complex near 240 nm. Dependence of the peak intensity on pH at various q values ($\text{q =}\text{[}\text{Cu}{}^{\mathrm{2+}}\text{]}\text{[}\text{residue}\text{]}$) indicates the two steps of the complex formation. At q less than 0.64, the formation is described only with the first step. An average coordination number for Cu²⁺ at the first step was calculated to be about 2 by the method of Mandel and Leyte. The association constant of Cu²⁺ with the residue at the step was determined from the absorption data to be far smaller than that for the Cu²⁺-EDTA complex. The second step of the formation occurs in the case of large q but the absorption data for the second step cannot be obtained exactly due to precipitation.     

Sintering of Si3N4-Y2O3-Al2O3

Sintering kinetics of the system Si₃N4-Y2O₃-Al₂O3 were determined from measurements of the linear shrinkage of pressed disks sintered isothermally at 1500° to 1700°C. Amorphous and crystalline Si₃N₄ were studied with additions of 4 to 17 wt% Y₂O₃ and 4 wt% A1₂O₃. Sintering occurs by a liquid-phase mechanism in which the kinetics exhibit the three stages predicted by Kingery's model. However, the rates during the second stage of the process are higher for all compositions than predicted by the model. X-ray data show the presence of several transient phases which, with sufficient heating, disappear leaving mixtures of β ' -Si₃N₄ and glass or β '-Si₃N₄, α '-Si₃N₄, and glass. The compositions and amounts of the residual glassy phases are estimated.     

Participation of lewis base on vinyl chloride polymerization with Al(C2H5)3CCl4 catalyst system

The polymerization of vinyl chloride has been investigated using an $\text{Al}\text{(}\text{C}{}_2\text{H}{}_5\text{)}{}_3\text{CCl}{}_4$ catalyst system in the presence of various Lewis bases. Effective Lewis bases are γ-butyrolactone, diglyme and diethylenetriamine which are multidentate. The rate of polymerization is dependent not only on the basicity of the Lewis base used but also on a coordination number of one. The latter is the predominant factor. For the effect of polymeric amines, a tentative hypothesis is discussed.     

The System Si3N4-SiO2-Y2O3

Subsolidus phase relations were established in the system Si₃N₄-SiO₂-Y₂O₃. Four ternary compounds were confirmed, with compositions of Y₄Si₂O₇N₂, Y₂Si₃O₃N₄, YSiO₂N, and Y₁₀(SiO₄)₆N₂. The eutectic in the triangle Si₃N₄-Y₂Si₂O₇-Y₁₀(SiO₄)₆N₂ melts at 1500°C and that in the triangle Si₂N₂O-SiO₂-Y₂Si₂O₇ at 1550°C. The eutectic temperature of the Si₃N₄-Y₂Si₂O₇ join was ∼ 1520°C.     

Compact Swelling in Bi1.4Pb0.6Sr2Ca2Cu3.6Oy During the Formation of High-Tc Superconducting Phase

Compact swelling in Pb-doped Bi-Sr-Ca-Cu-O superconductor has been studied by observing the effects of the size of calcined powders, volatilization of materials, and sintering of high- T _c (2223) powders. The bulk density increases at the early stage of sintering, for about 20 h, and then decreases. Densification occurs when the low- T _c (2212) phase and a liquid phase exist, whereas dedensification occurs with the formation of the 2223 phase regardless of the presence of the liquid. Gas evolution from specimens does not appear to be responsible for compact swelling. Compact swelling is explained by anisotropic growth of thin, platelike 2223 grains in random orientation. When 2223 grains grow in a preferred direction, compact swelling is suppressed.