有机敏化剂插层层状氢氧化铽纳米复合体的合成与发光性质

选择两种有机物对苯二甲酸(TA)和苯甲酸(BA)作为敏化剂,通过在水热条件下的离子交换反应,成功将其以有机阴离子形式插层至层状铽氢氧化物而获得纳米复合体。荧光性质测定表明TA^2-和BA^-通过有效的能量转移均增强了Tb³⁺的特征绿色荧光发射,并且TA^2-的敏化增强能力大于BA^-。从能级匹配角度讨论了敏化剂和Tb³⁺之间能量转移的机理。     

多色发光层状稀土氢氧化物/聚甲基丙烯酸甲酯复合荧光薄膜的组装

本文通过水热法合成了含有3种不同稀土离子的层状稀土氢氧化物(Gd0.5Tb0.5-xEux)2(OH)5NO3.nH2O,并选择有机物水杨酸(HSA)作为敏化剂,通过在水热条件下的离子交换反应,成功将其以有机阴离子形式与层状稀土氢氧化物插层组装获得有机-无机杂化荧光材料(SA--LRHs∶xEu)。荧光性质测定表明,SA-通过有效的能量转移增强了Tb3+的特征绿色荧光发射,随着Eu3+含量的增加,Eu3+的特征红色荧光发射随之增强,而Tb3+的特征绿色荧光发射随之减弱。在此基础上,将发光颜色可调的有机-无机荧光材料与聚甲基丙烯酸甲酯(PMMA)复合组装出透明的荧光薄膜。     

多色发光层状稀土氢氧化物/聚甲基丙烯酸甲酯复合荧光薄膜的组装

本文通过水热法合成了含有3种不同稀土离子的层状稀土氢氧化物 (Gd_0.5Tb_0.5-xEu_x)₂(OH)₅NO₃·nH₂O, 并选择有机物水杨酸(HSA)作为敏化剂, 通过在水热条件下的离子交换反应, 成功将其以有机阴离子形式与层状稀土氢氧化物插层组装获得有机-无机杂化荧光材料(SA^--LRHs:xEu)。荧光性质测定表明, SA^-通过有效的能量转移增强了Tb³⁺的特征绿色荧光发射, 随着Eu³⁺含量的增加, Eu³⁺的特征红色荧光发射随之增强, 而Tb³⁺的特征绿色荧光发射随之减弱。在此基础上, 将发光颜色可调的有机-无机荧光材料与聚甲基丙烯酸甲酯(PMMA)复合组装出透明的荧光薄膜。     

直接脱碳酸化制备有机离子插层的层状双氢氧化物

层状双氢氧化物(Layered double hydroxide, LDH)是一种具有阴离子可交换性质的层状无机材料, 由于其具有多种功能性质, 已被广泛应用于催化^[1~3]、酸吸附剂^[4]、传感器^[5]及聚合物填料^[6~8]等领域. 传统的共沉淀法制备的LDH结晶度低、尺寸小(直径通常小于100 nm). 1998年, Costantino等^[9]采用均匀沉淀法制备出了高结晶度、大尺寸(微米量级)且层间具有CO₃^2-的LDH(LDH-CO₃), 引起了人们的极大兴趣. 为解决LDH-CO₃难于交换和剥离的难题, Iyi等^[10,11]采用两步法制备了层间具有NO₃^- 或有机阴离子的LDH, 即首先采用 HCl-NaCl混合溶液将LDH-CO₃转化成为LDH-Cl, 然后再采用过量的阴离子进行交换制备LDH-NO₃或有机阴离子插层的LDH.     

微波法合成乙二醇插层镍铝层状双金属氢氧化物

乙二醇(EG)插层层状双金属氢氧化物(LDH)可作为层间催化反应器,用于原油中环烷酸与EG的酯化脱酸反应,但其合成过程需要较长时间。 以硝酸根型镍铝LDH为前体,在KOH促进下,采用微波辅助的离子交换法合成EG插层LDH,省时节能,提高效率。 考察了微波时间、微波温度和微波功率对EG插层LDH结构的影响。 并用XRD、FT-IR和TG-DSC等比较了微波法和常规方法合成的EG插层LDH的性质。 结果表明,微波辐射能提供高能量,促进待交换阴离子向层间的扩散,并减弱层板与层间原有阴离子间的作用力,在微波温度为120 ℃,微波时间为10 min和微波功率550 W的条件下,即可得到结晶度高的EG插层LDH。 微波法合成的EG插层LDH与常规方法合成的具有相似的性质和更高的结晶度,而合成时间可由12 h大幅缩短至10 min。     

层状稀土氢氧化物杂化发光材料研究进展

层状稀土氢氧化物(LRHs)是一类具有二维层状结构的新型无机层状功能材料.由于LRHs具有可变的组成、丰富的插层化学行为以及稀土离子特有的荧光性质等优点,因此是一种很有发展潜力的新型发光功能材料.本文综述了层状稀土氢氧化物杂化发光材料的研究进展,探讨了主客体间相互作用对其光物理性质及稳定性的影响,为实现层状稀土氢氧化物杂化发光材料在光学器件领域(LED照明和光纤维等)及生命分析领域的应用提供了重要的理论依据.     

聚合物/层状硅酸盐插层纳米复合材料的研究

简述了聚合物 /层状硅酸盐插层纳米复合材料方面的研究进展。阐述了层状硅酸盐的结构与性质以及纳米复合材料形成过程的热力学原理。重点介绍了尼龙、聚丙烯等聚合物的层状硅酸盐插层纳米复合材料的现状和技术发展趋势     

层状复合氢氧化物的有机改性方法及应用研究进展

层状复合氢氧化物(LDHs)因其化学组成可调、比表面积大、生物相容性好等特点,目前在环境、能源和生物医药等领域广受关注.然而, LDHs在合成过程中由于其分子内作用力易发生团聚而导致其在基体中的分散不均匀,极大地限制了LDHs在实际中的应用.有机改性是改善LDHs分散性的有效方法,从表面改性和插层改性两个方面综述了近年来LDHs的有机改性方法,并介绍了其在阻燃、吸附、催化、气体阻隔、发光、储能和生物医药材料等领域的应用.最后对改性后LDHs未来的研究方向和应用领域进行了展望.     

原位聚合法制备聚丙烯酸甲酯/ZnAl层状双氢氧化物插层纳米复合材料及其形貌特征

近 2 0年来 ,聚合物 /层状无机物纳米复合材料引起了广泛关注 ,与聚合物材料相比 ,该类纳米复合材料在力学、热稳定性、阻燃、气体阻隔等性能方面都有显著增强 .但所报道的绝大部分无机物均采用蒙脱土为代表的层状硅酸盐[1～ 3] ,而以层状双氢氧化物 (Layered double hydroxide,LDH)为基础制备的聚合物 /层状无机物纳米复合材料的报道极少 .LDH是由水镁石结构中的二价阳离子 (M2 + )被三价阳离子 (M3+ )取代而形成的 ,层上产生的剩余正电荷被吸附在层间的阴离子平衡 .与层状硅酸盐相比 ,L DH层间电荷密度高 ,层与层之间相互作用强 ,导…     

用焙烧复原法插层组装有机层柱双氢氧化物

有机酸根插层双氢氧化物(简记为:LDHs OA)是制备具有特殊性质和功能的层柱材料的一类重要前驱体[1 3]。本文以Mg6Al2(OH)16CO2-3·6H2O(简记为MgAl CO2-3)和Zn6Al2(OH)16CO2-3·4H2O(简记为ZnAl CO2-3)为前体,用焙烧复原法将十四酸根(简记为14A)和十八酸根(简记为18A)分别插层组装到了MgAl LDHs和ZnAl LDHs层板间而制得了具有大的层间距、良好的结晶度和规整的层状结构的14A(18A)插层LDHs层柱材料(分别简记为MgAl 14A,mgAl 18A,ZnAl 14A,ZnAl 18A),用XRD谱、IR谱表征了插层交换产物的结构。1　实验部分1.1　仪…     

喜树碱插层的镁铝型层状双金属氢氧化物的合成及表征

采用共沉淀法把抗癌药物喜树碱（Camptothecin, CPT）插入层状双金属氢氧化物(layered double hydroxide, LDH)层间, 合成了CPT-LDH纳米杂化物。结果表明,在CPT-LDH纳米杂化物中,CPT在层间的排布方式有两种,即平行于层板的单层排列和垂直于层板的双层排列;缓释研究表明,CPT-LDH在pH 7.5的磷酸缓冲液中具有明显的缓释效果,其释放速率较相同pH值时CPT和LDH物理混合物的释放速率明显降低;考察了CPT-LDH的药物释放机理,在 pH 7.5的缓冲溶液中,释放过程受粒内扩散过程控制;CPT-LDH纳米杂化物的释放动力学符合准一级动力学过程。     

Preparation of New Layered Double Hydroxide,Co-TiLDH

Layer double hydroxide (LDH) is well known for its ability to intercalate anionic compounds. Most popular LDH is prepared only conventionally with bivalent and trivalent cations. In this study, Co-Ti LDH consisting of bivalent and tetravalent cations was prepared and characterized by chemical analysis, X-ray diffraction, IR spectra, thermal analysis and Scanning Electron Microscope (SEM). The experimental results indicate that the ageing procedure plays a vital role in the formation of Co-Ti LDH. The insertion of a cyanate anion into LDH was confirmed by chemical analysis and IR spectra. XRD patterns of the prepared LDH (Co-Ti-CNO) showed that the interlayer spacing of the LDH was 0.79 nm. The spacing was similar to that of usual LDH in which chloride or bromide anion is the guest. SEM images show that the morphology of Co-Ti LDH was a plate-like structure or a fibrous structure depending on the preparation conditions.This revised version was published online in July 2005 with a corrected issue number.     

Intercalation of Azo Compounds into Layered Aluminium Dihydrogentriphosphate and a Layered Double Hydroxide

The inner surfaces of inorganic layered compounds such as aluminium dihydrogen-triphosphate (ADHP) and layered double hydroxide (LDH) were modified by azo compounds. Upon intercalation of 4-phenylazoaniline and 4,4-azodianiline into ADHP, the interlayer spacing increased from 6.4 to 21.5 Å and 20.6 Å, respectively. The intensity of IR peaks due to P-–OH of ADHP and amino groups of guests decreased by the thermal treatment of the intercalates. The interlayer spacings also decreased to 16.9 Å and 16.7 Å, respectively, indicating a dehydration reaction between P–-OH and amino groups. The LDH inner surface was modified by the reaction with trans-p-phenylazobenzoylchloride (PAB-Cl). Upon surface modification, the interlayer spacing increased from 7.6 Å to about 27 Å. The absorption of this surface-modified LDH near 410 nm increased upon irradiation with UV light and decreased upon irradation with visible light, indicating the occurrence of trans–cis isomerization of PAB-Cl between the layers.     

Zn/Al层状双氢氧化物-聚氯乙烯纳米复合物的制备与性能

用共沉淀法制备油酸钾改性的Zn2+、Al 3+层状双氢氧化物(Zn/Al-LDH),以环己酮为溶剂,用溶液插层法制备了Zn/Al层状双氢氧化物-聚氯乙烯(PVC)纳米复合物。采用傅里叶红外(FT-IR)、X-射线衍射(XRD)、透射电镜(TEM)对复合材料的结构及形貌进行了表征,并用热分析仪、万能试验机和紫外分光光度计研究了复合物的热稳定性能、拉伸性能和紫外吸收性能。结果表明:Zn/Al-LDH纳米片层无序分散在PVC基体中;Zn/Al-LDH对PVC低温时的骨干脱氯化氢有促进作用;与PVC膜相比,复合膜的分解温度降低,高温碳化温度升高,复合膜的拉伸强度及断裂伸长率得到提高,在300~380nm具有一定的紫外吸收性能。     

Mg-Al-NO_3层状双氢氧化物的制备及性能研究

制备了带正电荷的Mg-Al-NO_3层状双氢氧化物（LDH）,并对其组成、形貌、 电性能、离子交换性能等各种性质进行了表征。实验结果表明,所制备的正电纳米 颗粒具有可调控的层间自由空间。该方法为进一步研究聚合物/纳米复合材料提供 了一个合成前驱体的方法。     

超分子结构草甘膦插层水滑石的组装及结构研究

提出了一种新的绿色农药缓释剂模型——超分子结构草甘膦缓释剂.依据插层组装理论,以阴离子层状材料镁铝水滑石(MgAl-LDH)为插层主体,以除草剂草甘膦为插层客体,由共沉淀法一步组装得到超分子结构草甘膦插层镁铝水滑石(MgAl-LDH-gly).通过对MgAl-LDH-gly的结构、主客体相互作用及化学组成确认,建立了MgAl-LDH-gly的近似超分子结构模型,并对其缓慢释放草甘膦的可行性进行了分析.     

Hydrothermal Synthesis of Glutamic Acid/Layered Double Hydroxide Compounds

In this article, glutamic acid (Glu) was intercalated into the Zn-Al layered double hydroxides (Zn-Al LDHs) by hydrothermal method. The influence of the molar ratio of Zn/Al/Glu (R values for short), the aging time, and the pH value of the washing solution was systematically studied. The resulting Glu-LDH compounds were characterized by x-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), and scanning electron micrograph (SEM). The XRD results showed that the relative diffraction intensity first increased then decreased as the R value and the pH value of the washing solution increased. Moreover, the crystallinity degree decreased gradually with the increase of the aging time. The absorption peaks attributed to the stretch of (R-COO^?) were observed in the FTIR spectra. SEM graphs indicated that the morphology of the particles was largely influenced by the synthesis conditions.     

Enhancing Electrocatalytic Activity through Liquid-Phase Exfoliation of NiFe Layered Double Hydroxide Intercalated with Metal Phthalocyanines in the Presence of Graphene

Earth-abundant transition-metal-based catalysts are attractive for alkaline water electrolysis. However, their catalytic properties are often limited by their poor electrical conductivity. Here, we present a strategy for enhancing the electrical conductivity of NiFe layered double hydroxide (LDH) in order to further improve its properties as an electrocatalyst for the oxygen evolution reaction (OER) in alkaline media. We show that NiFe LDH containing metal tetrasulfonate phthalocyanine in the interlayers between the NiFe oxide galleries can be coupled with graphene during liquid-phase exfoliation by taking advantage of their π-π stacking capabilities. A substantial enhancement in the electrocatalytic activity of NiFe LDH with respect to the OER was observed. Moreover, the activity and selectivity of the catalyst materials towards the oxygen reduction reaction were investigated, demonstrating that both the metal hydroxide layer and the interlayer species contribute to the electrocatalytic performance of the composite material.