原位合成CoPc/SnO2的键合特性及可见光光催化活性

报道了酞菁钴(CoPc)分子原位自组装于纳米SnO2颗粒表面, CoPc大环分子与SnO2表面形成Co—O轴向相互作用, 测定了原位合成方法(标记为i)制备的CoPc/SnO2(i)与浸渍法(标记为d)制备CoPc/SnO2(d)间的结合特性, 并进行了可见光光催化表征及CoPc敏化机理探讨. 结果表明, 在结合位点数相当的情况下, CoPc/SnO2(i)结合常数比CoPc/SnO2(d)的高两个数量级, 前者的光催化效率亦比后者高32.5%(光照150 min), 且CoPc/SnO2(i)光催化稳定性较高(重复十次循环使用). 其CoPc敏化SnO2的机理为, 由于敏化剂与半导体之间存在的强相互作用, 不仅增强了光生电荷在CoPc的LUMO与SnO2半导体导带间的导入效率及光生电荷对的分离效率, 而且提高了敏化剂的负载稳定性与循环光催化效率的持续性.     

Binding Characteristics of CoPc/SnO2 by In-situ Process and Photocatalytic Activity under Visible Light Irradiation

Cobalt phthalocyanine (CoPc) was synthesized and self-assembled on the surface of nanoscale tin dioxide (SnO₂) by in-situ process, marked as i, and Co-O interaction was verified to conjugate axially between macromolecule (CoPc) and SnO₂ in CoPc/SnO₂(i). The results indicated that the binding constant of CoPc/SnO₂(i) was two-order higher than that of CoPc/SnO₂(d) synthesized by dipping process, marked as d, while the numbers of binding sites were comparable in both samples. The degradation rate in the photocatalytic activity of CoPc/SnO₂(i) was 32.5% higher than that of CoPc/SnO₂(d) under visible-light irradiation for 150 min due to the effective electron separation and energy injection from LUMO of CoPc to conduction band of SnO₂ for CoPc/SnO₂(i) based on the strong interaction between CoPc and SnO₂. The degradation recyclability of CoPc/SnO₂(i) retained 48.8% in 10 times under the same circular photocatalytic process.     

PREPARATION AND ELECTROCHEMICAL CHARACTERISTICS OF POLYMER ELECTROLYTE MEMBRANES BASED ON SAN/PVDF-HFP BLENDS

A copolymer of poly(acrylonitrile-co-styrene) (SAN) was synthesized via an emulsion polymerization method. Novel polymer electrolyte membranes cast from the blends of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), SAN and fumed silica (SiO2) are microporous and can be used in polymer lithium-ion batteries. The membrane shows excellent characteristics such as high ionic conductivity and good mechanical strength when the mass ratio between SAN and PVDF-HFP and SiO2 is 3.5/31.5/5. The ionic conductivity of the membrane soaked in a liquid electrolyte of 1 mol/L LiPF6/EC/DMC/DEC is 4.9×10-3 S cm-1 at 25℃. The membrane is electrochemical stable up to 5.5 V versus Li /Li in the liquid electrolyte. The influences of SiO2 content on the porosity and mechanical strength of the membranes were studied. Polymer lithium-ion batteries based on the membranes were assembled and their performances were also studied.     

Prediction of branch on branch and topological characteristics of low‐density polyethylene polymerization by a novel stochastic approach

A novel approach using Monte Carlo method applied to simulation of low‐density polyethylene (LDPE) polymerization in tubular reactor showing topological characteristics, and the comprehensive kinetic mechanism has been taken into consideration. The results show the precise details of the structure of a chain in the three levels of the backbone, the main branches, and branches on branch. The chain types include dead polymer, dead polymer with unsaturated end, and live polymer with primary radical, secondary radical, and tertiary radical. In this work, the branches on branch were identified in terms of number, length, and position of the branch. Sixty percent of branches on branch are 1 to 5 carbons long, and the longest branch on branch is about 50 carbons. Thus, this study provides a tool for more accurately mapping the polymer chains architecture, superior to determine the number, and position of long‐ and short‐chain branches in past researches. Finally, this approach will advance the prediction of microstructure‐related properties of polymer one step further.     

含油污泥的热解特性研究

利用热重 傅里叶变换红外光谱联用仪与管式电阻炉对含油污泥热解特性进行了研究,分析了热解过程及影响因素（污泥性质与升温速率）,并由气体析出特性研究了热解机理。结果表明,热解过程包括水分挥发、轻质油挥发、重质油热解、半焦炭化与矿物质分解五种反应,矿物油反应集中发生在220℃～480℃。污泥性质影响因素中,产生环节最为显著,罐底泥、污水污泥失重明显而落地油泥失重不明显,矿物质组分含量越高,挥发分转化率越低;而污泥的油源基属影响较小。升温速率越大,反应进行的越快,挥发分转化率降低。热解机理包括矿物油含氧官能团裂解,链烃及侧链上的断链,环化、芳构化以及缩合脱氢。     

负载型CuO—ZnO／γ—Al2O3催化剂抗硫中毒性能的研究

采用XPS、TPR法证明浸渍法制备的CuO-ZnO/Al_2O_3催化剂中的CuO、ZnO和γ-Al_2O_3之间存在强相互作用,Cu量≤7.0wt%,Zn量≤11Wt%时,CuO和ZnO以单分子层分散在γ-Al_2O_3上.催化剂表面Cu和Zn实际含量的比值远小于配制时的比值(Cu/Zn=2),表明ZnO比CuO优先分布在表面.因ZnO比CuO更易和S作用生成ZnS,ZnO在表面的大量存在减少了Cu被S中毒的机率;另外CuO单层分散在Al_2O_3上,还原后生成的Cu~0,由于γ-Al_2O_3的拉电子作用使其处于缺电子状态(CU~(?+)),加上催化剂表面可能有部分CuO和Al_2O_3形成尖晶石,使一部分Cu以Cu~(n+)存在,Cu~((?)+)或Cu~(n+)对S的吸附弱.以上两个原因使负载型铜催化剂具有良好的抗硫中毒性能.     

Sr2SiO4∶Dy3+材料制备及发光特性

采用高温固相法制备了Sr2SiO4∶Dy3+发光材料. 在365 nm紫外光激发下, 测得Sr2SiO4∶Dy3+材料的发射光谱为一个多峰宽谱, 主峰分别为486, 575和665 nm; 监测575 nm的发射峰, 所得材料的激发光谱为一个多峰宽谱, 主峰分别为331, 361, 371, 397, 435, 461和478 nm. 研究了Dy3+掺杂浓度对Sr2SiO4∶Dy3+材料发射光谱强度的影响. 研究结果显示, 随着Dy3+浓度的增大, 黄、蓝发射峰比值(Y/B)也逐渐增大; 随着Dy3+浓度的增大, 575 nm发射峰强度先增大后减小. 加入电荷补偿剂Li+, Na+和K+均提高了Sr2SiO4∶Dy3+材料的发射光谱强度, 其中以Li+的情况最为明显.     

Structures and electrochemical characteristics of several kinds of alloys

The structures and the electrochemical characteristics of La_0.7−x Ce_xMg_0.3Ni_2.8Co_0.5 (x = 0.1–0.5) alloy, Ti_0.25−x Zr_xV_0.35Cr_0.1Ni_0.3 (x = 0.05–0.15) alloy and AB_3<x<5-type alloy, which are the representative examples of AB₃-type alloy, solid solution alloy and non-AB₅-type alloy, respectively, have been investigated, and the performances of MH-Ni battery in which AB_3<x<5 type alloy is used as the negative electrode material are examined at relatively low temperature.     

A fluorescent chemical sensor for Hg(II) based on a corrole derivative in a PVC matrix

A fluorescent chemical sensor for Hg(II) using 5,10,15-tris(pentafluorophenyl)corrole (H₃(tpfc)) as fluorophore is described in this paper. The response of the sensor is based on the fluorescence quenching of H₃(tpfc) by coordination with Hg(II). H₃(tpfc) based sensor shows a linear response towards Hg(II) in the concentration range from 1.2 × 10⁻⁷ to 1.0 × 10⁻⁴ M, with a working pH range from 5.0 to 8.0. The response time for Hg(II) concentration ≤1.0 × 10⁻⁵ M is less than 5 min. The sensor shows good selectivity for Hg(II) over alkali, and alkaline earth, and most of transition metal cations. The effect of the composition of the sensor membrane has been studied and the experimental conditions optimized. The corrole based sensor membrane can be easily regenerated just by washing with blank buffer solution after each measurement. The sensor has been used for determination of Hg(II) in water samples with satisfactory results.     

雎水流域的水化学特征及其地表水与地下水的相互转化

为了解特定流域的水化学特征及其运移和转化的历史,为水资源科学管理提供依据,分析了小流域雎水河的水化学特征。结果表明:(1)雎水河流域主要是大气降水补给的地矿化度的溶滤水。(2)雎水河全线都是地下水补给地表水。(3)部分泉点矿化度相对较高与SO24-较高有关,可能是因为流经了含煤地层。