多金属氧酸盐杂化催化剂光催化降解有机杀虫剂六氯苯

 通过自组装技术制备了一系列多金属氧酸盐-有机胺-分子筛杂化催化剂K5［M(H2O)PW11O39］-(EtO)3Si(CH2)3NH2-MCM-48,用XRD,ICP-AES,UV/DRS,FT-IR,31P MAS NMR和N2吸附等手段对其组成和结构进行了表征,并以有机杀虫剂六氯苯为探针分子考察了其光催化活性. 结果表明,多金属氧酸盐杂化催化剂的光催化降解活性高于直接光解,能有效地降解污水中的六氯苯,且易分离,可循环使用.     

多酸-有机聚合物超分子自组装杂化材料

多酸具有多样的拓扑结构和优异的理化性质,在催化、光电材料和药物等领域显示出广阔的应用前景。多酸-有机聚合物超分子自组装杂化材料不仅有效融合了多酸丰富的功能特性和有机聚合物良好的加工性,而且其有序的自组装结构还赋予材料更多优异的功能调控性。静电复合、氢键作用、共价键连等超分子策略是将多酸引入到聚合物基质中的有效方法。本文总结了多酸-有机聚合物超分子杂化材料近几年的最新研究进展,重点介绍了这类杂化材料的构筑策略、其有序的自组装行为以及超分子功能特性的调控等。     

无机氧化物复合纳米材料的制备、表征及其对蓝色染料光催化降解的探讨

采用化学共沉淀法合成Fe0.6Cr0.4/Bi7MnO12.5复合纳米材料，用透射电子显微镜（TEM）、X射线粉末衍射分析（XRD）、红外光谱（FTIR）等手段对材料进行表征，用Na2CO3溶液浸渍复合纳米晶作为催化剂，对蓝色染料进行光催化降解探讨。     

有机-无机多金属氧酸盐[CTMA]_6SiW_(11)NiO_(39)的合成及其光催化性能研究

多金属氧酸盐(POM)是指由多金属杂原子按一定的结构通过氧原子配位桥联而成的一类化合物的总称,按照阴离子结构可将其分为Keggin、Dawson、Anderson、Waugh等多种类型[1].     

多金属氧酸盐/TiO2介孔杂化材料的合成及光催化性能研究

采用蒸发诱导自组装法合成了介孔TiO2,并将表面含有Si-OH基团的钨磷酸盐衍生物(Bu4N)3PW11O39-[O(SiOH)2](TBAPW11Si2)嫁接到乙醇回流脱模的介孔TiO2上,合成了TBAPW11Si2/TiO2介孔杂化材料.采用IR、XRD、N2吸附-脱附、TEM、ICP-AES对样品的结构和组成进行了表征.结果表明,TBAPW11Si2与TiO2之间的共价键联是通过表面Si-OH和Ti-OH间的缩合进行的;TiO2表面足够的Ti-OH基团和一定温度的焙烧是这一缩合的必要条件.与TiO2载体相比,嫁接了TBAPW11Si2的杂化样品,锐钛矿相的结晶度略有增加;但表面积、孔容和孔径均有所减小,且随TBAPW11Si2负载量的增加而降低.光催化降解甲基橙的结果显示,杂化样品表现出比载体TiO2高得多的催化活性,甚至与高结晶度的商品光催化剂P25相当,显示出多金属氧酸盐-TiO2协同作用的优越性.     

SnⅡ取代的Keggin型多金属氧酸盐的合成及光催化性能

合成了Sn~(Ⅱ)取代的Keggin型钨磷、钨硅多金属氧酸盐,用IR、电子光谱、~(31)P NMR测试技术对样品进行了表征,表征结果显示,合成化合物为纯的Sn~Ⅱ取代多金属氧酸盐,无Sn~Ⅳ取代物存在,其中Sn~(2 )未进入空穴八面体的中心,其阴离子的对称性介于相应的饱和与缺位结构之间。继而研究了此类化合物对于几种水溶性染料的光催化降解性能。结果表明,所制备的Sn~Ⅱ取代的钨硅多金属氧酸盐具有高的光催化活性,活性高于一般常用的PW_(12)、SiW_(12)化合物。特别是Sn~Ⅱ取代的钨硅多金属氧酸盐,即使在室内自然日光下对甲基橙和亚甲基蓝的光降解也呈现出很高的催化活性,反应7 h,降解率可达90％以上。对光催化机理的研究表明, Sn~Ⅱ取代的钨磷、钨硅多金属氧酸盐发生O→W荷移跃迁所需的能量较小,因此低能量的光照就可激发其HOMO能级上的电子,引发光催化反应,大大提高了光能利用率。     

有机金属聚合物/多酸纳米杂化LB膜的制备与光电性质研究

以含有共轭大π键的有机金属聚合物(OMP)作有机组分, 以Keggin结构和Dawson结构钨(钼)磷杂多酸作无机组分, 以十八胺为辅助成膜剂, 用LB技术制备了3种新型有机金属聚合物/十八铵/杂多阴离子OMP/ODA/HPA (HPA＝PMo₁₂, PW₁₂, P₂Mo₁₈)杂化LB膜. 用π-A曲线﹑UV-vis吸收光谱﹑荧光光谱﹑原子力显微镜(AFM)﹑扫描隧道显微镜(STM)和表面光电压谱(SPS)对标题LB膜的成膜性能及光电性质进行了研究, 结果表明标题杂化LB膜的崩溃压为26.8 mN/m, 在可见光区有较强的光电压响应, 并有好的发光性质. 当电压为±8.0 V时, 隧道电流是－0.1～－2.3 nA.     

K8[Ni(H2O)CuW11O39]/PANI/ZnS复合材料的制备、表征及光催化性能

本文使用静电自组装法将PANI/ZnS与K_8[Ni(H_2O)CuW_(11)O_(39)](NiW_(11)Cu)复合为新的三元复合材料K_8[Ni(H_2O)CuW_(11)O_(39)]/PANI/ZnS(NiW_(11)Cu/PANI/ZnS)。运用FT-IR、UV、XRD、SEM-EDS、N_2吸附-解吸等分析方法表征NiW_(11)Cu/PANI/ZnS。以NiW_(11)Cu/PANI/ZnS为催化剂光催化降解甲基紫,考察其光催化性能。结果表明:当甲基紫pH为2,浓度为15 mg·L~(-1),NiW_(11)Cu/PANI/ZnS为10 mg时,甲基紫的降解率可达91.98%。     

两个基于多金属氧酸盐和冠醚基超分子阳离子的有机无机杂化材料的合成及晶体结构

以二苯并18-冠-6,3-氟-4-甲基苯铵盐以及多金属氧酸盐[Mo₆O₁₉]^2-为原料,使用溶剂挥发法合成了有机无机杂化材料[（3-F-4-MeAnis）（DB[18]crown-6）]₂[Mo₆O₁₉]·2CH₃CN （1）（3-F-4-MeAnis=3-氟-4-甲基苯铵盐;DB[18]crown-6=二苯并18-冠-6）;以18-冠-6,2-氟-4-甲基苯铵盐以及多金属氧酸盐[SMo₁₂O₄₀]^2-为原料,运用H管扩散法制备了晶体材料[（2-F-4-MeAnis）（[18]crown-6）]₂[SMo₁₂O₄₀]·2CH₃CN （2）（2-F-4-MeAnis=2-氟-4-甲基苯铵盐;[18]crown-6=18-冠-6）。通过红外光谱、元素分析、热重分析和X射线单晶结构分析对化合物进行了表征。结构分析表明,晶体1和2通过非共价键自组装作用构建而成,冠醚基超分子阳离子是通过N-H…O氢键作用形成。在晶体1和2中,超分子阳离子和多酸阴离子交错堆积形成包合物结构,沿着a轴方向观察,发现每个多酸阴离子被6个超分子阳离子包围着形成六边形堆积结构。通过晶体结构研究和热重分析表明,二苯并18-冠-6中的苯环在维持晶体1的稳定性方面具有重要的作用。     

WO_3纳米片:基于无机-有机杂化前驱物的制备及光催化性能

以商业三氧化钨粉末做为钨源,通过合成WOx-EDA(EDA=乙二胺)无机-有机杂化纳米带为前驱物,再加盐酸酸化,迅速得到中间产物正交型钨酸单晶纳米片。再在空气气氛下,将中间产物在管式炉中煅烧2 h,最终得到单斜型三氧化钨单晶纳米片。一系列对比实验的结果表明,在由杂化纳米带转变成钨酸纳米片时,反应温度、反应时间、酸化浓度等实验参数对产物的结构和形貌有着很大的影响。通过计算,制得的三氧化钨纳米片带隙为2.48 eV。对比于商业三氧化钨粉末,三氧化钨纳米片在可见光降解罗丹明B(RhB)中表现出更优越的性能。     

两个紫精-多酸杂化材料的合成、结构及其光致变色和光催化性质

分别利用1,1''-二甲基-4,4''-联吡啶(甲基紫精,MV)二氯化物和1,1''-二乙基-4,4''-联吡啶(乙基紫精,EV)二溴化物的阳离子作为电子受体,富电子的杂多酸阴离子作为电子给体,合成了 2 个新的紫精-多酸杂化晶态材料：(MV)₂[HPW^Ⅴ₂W^Ⅵ₁₀O₄₀]·2H₂O (1)和(EV)₂[Mo₈O₂₆] (2),并解析了其单晶结构,在化合物 1和 2中,阴、阳离子间均存在氢键相互作用。2具有光致变色性能,光响应时间为1 min以内。通过固体漫反射、电子顺磁共振和理论计算等手段,探究了2的光致变色机理。1和2对光降解有机染料(亚甲蓝、盐酸副玫瑰苯胺和罗丹明6G)均具有一定的催化性能。     

两个紫精-多酸杂化材料的合成、结构及其光致变色和光催化性质

分别利用1,1''-二甲基-4,4''-联吡啶(甲基紫精,MV)二氯化物和1,1''-二乙基-4,4''-联吡啶(乙基紫精,EV)二溴化物的阳离子作为电子受体,富电子的杂多酸阴离子作为电子给体,合成了 2 个新的紫精-多酸杂化晶态材料：(MV)₂[HPW^Ⅴ₂W^Ⅵ₁₀O₄₀]₂·2H₂O (1)和(EV)₂[Mo₈O₂₆] (2),并解析了其单晶结构,在化合物 1和 2中,阴、阳离子间均存在氢键相互作用。2具有光致变色性能,光响应时间为1 min以内。通过固体漫反射、电子顺磁共振和理论计算等手段,探究了2的光致变色机理。1和2对光降解有机染料(亚甲蓝、盐酸对甲苯胺和罗丹明6G)均具有一定的催化性能。     

一例Wells-Dawson型铌钨混配多酸的合成及光催化性质

在双氧水存在条件下,合成了一例Wells-Dawson型铌钨混配多酸K3.5Na4[H4.5（NbO2）6P2W12O56]·12.5H2O（1）,X射线单晶结构分析表明,化合物1的多阴离子是一个六过氧铌基团取代的P2W12衍生物.六个铌原子分别与五个来自多酸框架上的氧原子和一个端位的过氧单元配位.另外,对化合物1的光催化产氢性能进行了初步研究.     

Preparation, characterization and photocatalytic activity of visible light driven chlorine-doped TiO2

A novel chlorine-doped titanium dioxide catalyst with visible light response was prepared by hydrolysis of tetrabutyl titanate in hydrochloric acid. The catalyst samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS). Results showed that the doped element of Cl lowered the temperatures of phase transformation of TiO₂ from amorphous to anatase and from anatase to rutile. The absorption edge of chlorine-doped TiO₂ calcined at 300°C shifted to visible light region. X-ray photoelectron spectroscopy results proved that chlorine existed in the TiO₂ crystal lattice as anion. The photocatalytic degradation of phenol showed that under visible light (λ > 400 nm) irradiation, the chlorine-doped TiO₂ calcined at 300°C displayed the best performance, the degradation ratio of phenol was 42.5% after 120 min. Translated from Chinese Journal of Catalysis, 2006, 27(10): 890–894 [译自: 催化学报]     

异质结构AgCl/Bi2WO6微米球制备、表征及其光催化性能

首先利用水热法制备了由纳米片组装的粒径为1.5–2μm的Bi2WO6微球,然后在微球表面沉积了不同含量的AgCl (5 wt%,10wt%,20wt%,30wt%),制备了异质结构AgCl/Bi2WO6微球光催化剂.利用X射线粉末衍射、扫描电镜、透射电镜、红外光谱、紫外-可见漫反射吸收等手段对所制的光催化剂进行表征,并以紫外光和可见光分别为光源,罗丹明B为降解对象测试了其光催化活性,考察复合不同含量的AgCl对Bi2WO6光催化剂的性能影响.结果表明,沉积AgCl对Bi2WO6的晶体结构、表面性能和光吸收性能没有产生明显影响,但大幅度提高了Bi2WO6的紫外和可见光催化活性.当复合20wt%AgCl时, AgCl/Bi2WO6光催化活性最佳,紫外光下比纯Bi2WO6提高了2.2倍,可见光下提高了1倍.这主要是由于形成的AgCl/Bi2WO6异质结能有效抑制光生电子和空穴的复合,从而提了其光催化性能.     

铋掺杂介孔二氧化钛的制备及光催化动力学

以介孔分子筛(KIT-6)为载体,采用溶液浸渍法合成了铋(Bi)掺杂的介孔二氧化钛(TiO₂)光催化剂。利用XRD、TEM、SEM、XPS、N₂吸附-脱附法和拉曼光谱法等技术手段对材料的结构和形貌进行表征。通过紫外-可见吸收光谱法考察了催化剂对罗丹明B光催化降解效率,进一步考察了Bi的掺杂量对光催化反应速率的影响,并对光催化降解动力学进行了初步研究。结果表明,Bi掺杂的介孔TiO₂具有较窄的孔径分布(3~4 nm),而且吸收范围扩展到可见光区,其光催化活性明显高于商品TiO₂(P25)。随之Bi掺杂量的提高,反应速率常数也增大,其光催化降解罗丹明B的反应均符合准一级动力学方程。     

Biosynthesis and characterization of lead selenide semiconductor nanoparticles (PbSe NPs) and its antioxidant and photocatalytic activity

The current study fabricated novel lead selenide nanoparticles (PbSe NPs) by a simple biological benign process with Trichoderma sp. WL-Go. Ultraviolet–visible spectroscopy (UV–vis), Transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transfer infra-red (FTIR) spectroscopic analysis, Raman spectroscopy and Photoluminescence (PL) were used to characterize the physicochemical properties of the fabricated NPs. Synthesis at pH 8 with 0.5 g biomass of strain WL-Go and (1:1) mM of SeO₂: Pb(NO₃)₂ were the optimal synthesis conditions to achieving 10–30 nm cubic faced centered NPs. The PbSe NPs served as catalyst for investigating the antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and photodegradation ability of rhodamine B dye (10 mg/L). The results indicated that the NPs could eliminate up to 88.60% of free radicals after adding 600 g/mL NPs and could photodegrade 82% of rhodamine B in 30 min. Thus, this study provides new knowledge and strategies for the future use of an environmentally benign bio- catalytic PbSe NPs to efficiently eliminate free radicals and in treatment of persistent organic pollutants in wastewaters.     

Preparation, characterization and photocatalytic performance of Mo-doped ZnO photocatalysts

A series of Mo-doped ZnO photocatalysts with different Mo-dopant concentrations have been prepared by a grinding-calcination method.The structure of these photocatalysts was characterized by a variety of methods,including N 2 physical adsorption,X-ray diffraction(XRD),scanning electron microscopy(SEM),Fourier transform infrared(FT-IR) spectroscopy,photoluminescence(PL) emission spectroscopy,and UV-vis diffuse reflectance spectroscopy(DRS).It was found that Mo 6+ could enter into the crystal lattice of ZnO due to the radius of Mo 6+(0.065 nm) being smaller than that of Zn 2+(0.083 nm).XRD results indicated that Mo 6+ suppressed the growth of ZnO crystals.The FT-IR spectroscopy results showed that the ZnO with 2 wt.% Mo-doping has a higher level of surface hydroxyl groups than pure ZnO.PL spectroscopy indicated that ZnO with 2 wt.% Mo-doping also exhibited the largest reduction in the intensity of the emission peak at 390 nm caused by the recombination of photogenerated hole-electron pairs.The activities of the Mo-doped ZnO photocatalysts were investigated in the photocatalytic degradation of acid orange II under UV light(λ = 365 nm) irradiation.It was found that ZnO with 2 wt.% Mo-doping showed much higher photocatalytic activity and stability than pure ZnO.The high photocatalytic performance of the Mo-doped ZnO can be attributed to a great improvement in the surface properties of ZnO,higher crystallinity and lower recombination rate of photogenerated hole-electron(e-/h+) pairs.Moreover,the undoped Mo species may exist in the form of MoO3 and form MoO3 /ZnO heterojunctions which further favors the separation of e-/h+ pairs.     

Chemical synthesis, structural characterization, optical properties, and photocatalytic activity of ultrathin ZnSe nanorods

Ultrathin ZnSe nanorods in the cubic phase have been synthesized by the reaction of selenium and zinc oleate for 30 min at 240 °C. These nanorods showed an average diameter of 2.4 nm, which is much smaller than the Bohr size of bulk ZnSe. Thus, they exhibited a remarkable quantum size effect in terms of their optical properties. The formation of the ultrathin nanorods could be attributed to the oriented attachment mechanism, which was supported by the structure of the nanorods and the control experiments. The ultrathin nanorods were transferred into an aqueous solution by ligand exchange. The performance of these nanorods as a catalyst was examined, using the photodegradation of methyl orange as a model reaction. It was found that the ultrathin nanorods possessed better photocatalytic activities than conventional ones.     

多壁碳纳米管负载TiO_2复合器件可见光光催化降解RhB

采用溶胶-凝胶法制备了多壁碳纳米管(MWCNTs)负载的ITO/MWCNTs-TiO2/ITO复合器件,利用SEM、XPS、UV-Vis光谱等技术对复合样品进行形貌和结构表征,以液相罗丹明B(RhB)的可见光光催化降解为探针反应,评价MWCNTs-TiO2复合薄膜的催化活性.XPS结果表明MWCNTs与TiO2之间没有形成Ti-C键.I-V特性表明负载了MWCNTs的ITO/MWCNTs-TiO2/ITO复合器件的光电流增强.与空白TiO2薄膜相比,MWCNTs-TiO2复合薄膜的可见光光催化降解RhB的速率提高了3.2倍.MWCNTs并没有掺杂到TiO2晶格中,而是起到了类似光敏剂的作用,可在可见光激发下将导带电子转移到TiO导带上,经一系列反应降解RhB有机物.