Carbon dots/Bi_2WO_6 composite with compensatory photo-electronic effect for overall water photo-splitting at normal pressure

Overall water photo-splitting is a prospective ideal pathway to produce ultra-clean H_2 energy by semiconductors.However,the band structure of many semiconductors cannot satisfy the requirement of H_2 and O_2 production at the same time.Herein,we illustrate that carbon dots(CDs)/Bi_2 WO_6 photocatalyst with compensatory photo-electronic effect has enhanced activity for overall water photo-splitting without any sacrificial agent.In this complex photocatalytic system,the photo-potential provided by CDs makes the CDs/Bi_2 WO6(C-BWO) composite could satisfy the band structure conditions for overall water photo-splitting.The C-BWO composite(3 wt% CDs content) exhibits optimized hydrogen evolution(oxygen evolution) of 0.28 μmol/h(0.12 μmol/h) with an approximate 2:1(H_2:O_2) stoichiometry at normal pressure.We further employed the in-situ transient photovoltage(TPV) technique to study the photoelectron extraction and the interface charge transfer kinetics of this composite catalyst.     

具有聚集诱导发光特性的含氟有机金属配合物的研究进展

近年来,具有聚集诱导发光(aggregation-induced emission,AIE)特性的化合物由于在聚集态或固态发光量子效率较高而受到很多关注.含氟的功能化合物,由于氟原子的存在,往往具有独特的结构和物理、化学及生物学性质.根据中心金属和配体的种类,汇总了具有AIE性质的且含有氟代配体的有机金属配合物的研究进...     

反应型次氯酸荧光探针

生物体内的次氯酸是氯离子和过氧化氢(H2O2)由髓过氧化物酶(MPO)催化生成的,是生物体内最重要的活性氧(ROS)之一,在生理过程中发挥了至关重要的作用.但是,过量的次氯酸会导致一系列生理疾病,因此有效的识别和检测次氯酸备受研究者们的青睐.与传统检测方法相比,荧光探针具有选择性好、灵敏度高、可实时监测等诸多优势,因此...     

亚微米级Cu0/Fe3O4复合物多相催化过一硫酸盐降解有机污染物

过一硫酸盐催化活化技术因其可产生强氧化性活性氧化物种,可快速氧化降解并矿化有机污染物的优异性能而备受关注.本文成功制备了亚微米级Cu0/Fe3O4复合物,发现其能多相催化过一硫酸盐产生单线态氧降解有机污染物.首先,以CuCl2·2H2O,FeCl2·4H2O和FeCl3·6H2O为铜源和铁源,水合肼为还原剂,采用水热法在180oC反应24 h制备了亚微米级磁性Cu0/Fe3O4复合物.表征结果显示,所制材料为Cu0和Fe3O4的复合物,颗粒大小约为220 nm;单一相Cu0和Fe3O4晶体粒径分别为33.8和106.2 nm,而Cu0/Fe3O4复合物中Cu0和Fe3O4晶体粒径分别减为20.8和31.9 nm.这表明Cu0和Fe3O4复合降低了Cu0和Fe3O4晶体粒径,有利于Cu0和Fe3O4的分散.BET测试结果表明,Cu0/Fe3O4复合物比表面积为4.6 m2/g,与Cu0颗粒的(4.2 m2/g)相当,但远小于Fe3O4的(15.6 m2/g).制备的Cu0/Fe3O4复合物可有效催化过一硫酸盐产生单线态氧降解罗丹明B、亚甲基蓝、金橙II、苯酚和对氯酚.当Cu0/Fe3O4复合物的用量为0.1 g/L,过一硫酸盐浓度为0.5 mmol/L和初始pH为7时,Cu0/Fe3O4复合物可在30 min内完全降解20μmol/L的罗丹明B、亚甲基蓝、金橙II以及0.1 mmol/L的苯酚和对氯酚.对比试验显示,在相同条件下,Cu0和Fe3O4颗粒分别可以降解28%和20%的罗丹明B.这表明Cu0/Fe3O4复合物中的Cu0和Fe3O4晶体在催化过一硫酸盐降解污染物的反应中具有协同作用,这主要来源于Cu0/Fe3O4复合物中Cu0和Fe3O4的晶体粒径变小和更好的分散.采用分光光度法测定了降解反应液中铜和铁离子的溶出量.当Cu0/Fe3O4复合物的用量为0.1 g/L,过一硫酸盐浓度为0.5 mmol/L和初始pH为7时,反应60 min后,降解液中铜和铁离子的浓度分别为0.22和0.1 mg/L,仅占复合物中总铜和总铁量的1.1%和0.2%,表明Cu0/Fe3O4复合物具有较强的化学稳定性.所制Cu0/Fe3O4复合物具有超顺磁性,借助磁场实现快速分离回收,可循环利用五次,表明其优越的催化稳定性.通过加入乙醇和叠氮化钠,考察了Cu0/Fe3O4复合物催化活化过一硫酸盐体系中的活性氧化物种.发现100 mmol/L乙醇的加入对污染物的降解无明显影响,而加入同等量的叠氮化钠可完全抑制污染物的降解,表明Cu0/Fe3O4复合物催化活化过一硫酸盐产生的主要活性氧物种为单线态氧.采用电子顺磁共振谱进一步证实了单线态氧的生成.基于以上研究,Cu0/Fe3O4复合物催化活化过一硫酸盐的机理为Cu0/Fe3O4作为一个电子媒介加速过一硫酸盐和污染物之间的电子转移,从而导致污染物被快速降解.该反应机理不同于常见的金属催化过一硫酸盐产生硫酸根和羟自由基的反应机理.我们推测,电导性优良的Cu0在此催化反应中起着关键性作用.本催化方法可作为一种绿色的氧化技术用于环境污染物的氧化降解处理.     

Synthesis and characteristics of photopolymerized benzophenone

Photopolymerization is extensively used in today's industrial field due to its advantages of rapid reaction, environmental friendly, energy saving and economical. Benzophenone is a most common photoinitiator (PI) using in photopolymerization because of its superior ability to initiate acrylate monomers. However, the intrinsic nature of initiator molecules is that they migrate out of polymer network, which limits its application, especially in the domain of food packaging materials. A polymerizable PI 4‐methylbenzophenone acrylate (MBPAc) was synthesized by a facile procedure and characterized by ¹H NMR, ¹³C NMR, and MS analyses. A systematic study of the photopolymerization kinetics of MBPAc was explored by the Real‐Time Fourier Transform Infrared Spectrometer. The results show that the final conversion and photopolymerization rate of acrylate monomers are closely related to the factors of their chemical structure, viscosity, functionality and light intensity, which means MBPAc is an efficient PI. Ultraviolet‐visible Spectrophotometer and vitro cytotoxicity measurement results indicate that the noncytotoxic MBPAc shows significantly lower migration than its analogue. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 313–320     

Synthesis,Adsorptive, and Photocatalytic Properties of Carbon Nanotubes/TiO<Subscript>2</Subscript> Nanocomposite Photocatalysts

The carbon nanotubes/TiO₂ (CNTs/TiO₂) composite photocatalysts composed of TiO₂ nanoparticles and multiwalled carbon nanotubes (CNTs) were prepared by a facile hydrothermal method. The photocatalysts were characterized by a range of analytical techniques including X-ray powder diffraction, field emission scanning electron microscope, thermal gravimetric analysis and UV–Vis optical absorption spectra, etc. The amount of TiO₂ nanoparticles growing on CNTs could be tuned by adjusting the dosage of precursor in the reaction solution. Both the adsorptivity and photocatalytic activities of pure CNTs, pure TiO₂, and the CNTs/TiO₂ nanocomposites were tested by the removal of methylene blue from water in dark and under a simulated sunlight, respectively. By comparison, the improved photocatalytic activity of the CNTs/TiO₂ nanocomposite is mainly due to that the CNTs can disperse the active component of TiO₂ nanoparticles, provide a larger the specific surface area, as well as act as an electron sink to accelerate the separation of the photogenerated charges.     

A nonlinear regression model applied to kinetic studies of ester hydrolysis with a surface acoustic wave sensor

A non-linear regression model was derived for the simultaneous determination of the rate constant in alkaline hydrolysis of esters and the initial concentration of esters based on the linear relationship between the frequency response of the surface acoustic wave sensor system and the conductivity of the solution. The model was tested theoretically and experimentally with the methyl-, ethyl-, and n-propyl-acetate systems. The corresponding rate constants estimated at 25 degrees C are 0.147, 0.103 and 0.0671 respectively.     

中药指纹图谱的融合技术

中药指纹图谱作为中药材真伪鉴别及质量控制的有效手段,具有整体、宏观和模糊分析等特点。高效液相色谱是指纹图谱研究的主流方法,在中药质量控制中具有重要地位。针对栀子药材而言,包括3类主要物质：环烯醚萜苷类、有机酸类和色素类。仅采用一个特征波长下的色谱指纹图谱无法对栀子药材进行整体表达和全面评价。为此,     

在DBU存在下酞菁锰配合物的合成及溶剂影响

在强有机碱１，８－二氮杂双环［５，４，０］十一－７烯（简称ＤＢＵ）存在下，ＭｎＣｌ２与邻二氰基苯在某些二元醇溶剂中可高效合成Ｍｎ（Ⅱ）Ｐｃ（Ｐｃ表示酞菁），同时研究了不同溶剂对合成产物的物种及产率的影响和不同氧化态锰的酞菁配合物在一些醇溶剂中的互变现象