Electrochemical Determination of Phenolic Acids at a Zn/Al Layered Double Hydroxide Film Modified Glassy Carbon Electrode

A stable sensor for the determination of gallic acid (GA) and caffeic acid (CA) was fabricated by electrodeposition of Zn‐Al‐NO₃ layered double hydroxide film on a glassy carbon electrode (LDHf/GCE). A sensitive electrochemical method was achieved for the determination of GA and CA in a phosphate buffer solution (pH 3). The differential pulse voltammetry response of the LDHf/GCE to GA has a linear concentration range from 4 µM to 600 µM with a correlation coefficient of 0.9985 and the calculated detection limit of 1.6 µM at a signal‐to‐noise ratio of 3. The differential pulse voltammetry response of the LDHf/GCE to CA has a linear concentration range from 7 µM to 180 µM with a correlation coefficient of 0.9969 and the calculated detection limit of 2.6 µM at a signal‐to‐noise ratio of 3. The constructed sensor was applied to the determination of GA in commercial green tea samples.     

双(羟基)金属复合氧化物的表面改性

水滑石;硬脂酸;湿法表面改性;双(羟基)金属复合氧化物的表面改性     

Determination of Chlorpromazine Hydrochloride with a Layered Double Hydroxide Modified Glassy Carbon Electrode as a Nanocatalyst

We report a simple and sensitive voltammetric sensor for the determination of chlorpromazine (CPZ) based on Ni?Al layered double hydroxide (NiAlLDH) modified glassy carbon electrode (GCE). NiAlLDH was simply electrodeposited on GCE surface in a very short time. The response linear range was 1×10^?3–1×10^?9 mol L^?1, with a detection limit of 1×10^?9 mol L^?1. The NiAlLDH film showed well defined and well separate peaks for dopamine, ascorbic acid, uric acid and CPZ in the same solution. The proposed electrode was used to measure the active pharmaceutical ingredient of CPZ tablet as a real sample.     

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.     

Electrocatalysis Oxidation of GMP Based on Layered Double Hydroxide Functionalized with Anionic Surfactant and Room Temperature Ionic Liquid Modified Glassy Carbon Electrode

The electrocatalysis oxidation of guanosine‐5′‐monophosphate (GMP) was investigated on Mg‐Al layered double hydroxide (LDH) functionalized with sodium dodecyl sulfate (SDS) and room temperature ionic liquid (RTIL) modified glass carbon electrode (GCE). The cyclic voltammogram of GMP on the modified electrode (RTIL/ LDH‐SDS/GCE) exhibited a well defined anodic peak at 1.091 V in 0.2 mol·L^?1 pH 4.4 acetate buffer solution. The GMP oxidation was enhanced in the presence of anionic surfactant in the ?lms. The results suggest that the surfactant molecules intercalate the LDH layers to preconcentrate GMP molecules and the RTIL showed good ionic conductivity. The experimental parameters were optimized, the kinetic parameters were investigated and the probable oxidation mechanism was proposed. Under the optimized conditions, the oxidation peak current was proportional to GMP concentration in the range from 5.0×10^?7 to 1.0×10^?4 mol·L^?1 with the correlation coefficient of 0.9987 and the detection limit was 1.0×10^?7 mol·L^?1. The RTIL/LDH‐SDS/GCE showed a good electrochemical response to the oxidation of GMP and would be developed into a new biosensor.     

Electrochemical Detection of Rutin on Mg2Al‐Cl Layered Double Hydroxide Modified Carbon Ionic Liquid Electrode

In this paper a Mg₂Al‐Cl layered double hydroxide (Mg₂Al‐LDH) modified carbon ionic liquid electrode (CILE) was prepared and further used for the electrochemical detection of rutin. Cyclic voltammograms of rutin on Mg₂Al‐LDH/CILE were recorded with a pair of well‐defined redox peaks appeared in pH 2.5 phosphate buffer solution, which was ascribed to the electrochemical reaction of rutin. Due to the presence of Mg₂Al‐LDH on the electrode surface, the redox peak currents increased greatly and the electrochemical parameters were calculated. Under the optimal conditions the oxidation peak current was proportional to rutin concentration in the range from 0.08 μmol L^‐1 to 800.0 μmol L^‐1 with the detection limit on 0.0255 μmol L^‐1 (3σ). The fabricated electrode showed good reproducibility and stability, which was successfully applied to rutin tablet samples determination.     

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。     

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.     

Sensitive and Facile Determination of Catechol and Hydroquinone Simultaneously Under Coexistence of Resorcinol with a Zn/Al Layered Double Hydroxide Film Modified Glassy Carbon Electrode

A stable dihydroxybenzene sensor was fabricated by electrochemical deposition of Zn/Al layered double hydroxide film on glassy carbon electrode (LDHf/GCE). The sensitive and facile electrochemical method for the simultaneous determination of catechol (CA) and hydroquinone (HQ) under coexistence of resorcinol (RE) has been achieved at the LDHf/GCE in phosphate buffer solution (pH 6.5). Under the optimized conditions, the differential pulse voltammetry response of the modified electrode to CA (or HQ) shows a linear concentration range of 0.6 μM to 6.0 mM (or 3.2 μM to 2.4 mM) with a correlation coefficient of 0.9987 (or 0.9992) and the calculated limit of detection is 0.1 μM (or 1.0 μM) at a signal‐to‐noise ratio of 3. In the presence of 50 μM isomer, the linear concentration ranges for CA and HQ are 3.0 μM to 1.5 mM and 12.0 μM to 0.8 mM, respectively. The detection limits are 1.2 μM and 9.0 μM. Further, the proposed method has been performed to successfully detect dihydroxybenzene isomers in analysis of real samples, such as water and tea.     

水热处理对Co-Al双氢氧化物电容性能的影响

超级电容器;水热法;比容量;水热处理对Co-Al双氢氧化物电容性能的影响     

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。     

Highly Sensitive Nonenzymatic Glucose Sensor Based on 3D Ultrathin NiFe Layered Double Hydroxide Nanosheets

As a promising electrode material, Ni‐based nanomaterials exhibit a remarkable electrochemical catalytic activity for nonenzymatic glucose sensors. In this paper, Nickel–Iron layered double hydroxide (NiFe‐LDH) film electrode with ultrathin nanosheets and porous nanostructures was synthesized directly on Ni foam (NF) by a one‐step hydrothermal method. The as‐obtained NiFe‐LDH electrode was adopted for glucose detection without further treatment. As an integrated binder‐free electrode for glucose sensor, the NiFe‐LDH/NF hybrid exhibits a superior sensitivity of 3680.2 μA mM⁻¹ cm⁻² with a low limit of detection (0.59 μM, S/N=3) as well as fast response time (<1 s). An excellent selectivity from potential interference species such as ascorbic acid, uric acid and Cl⁻ ions and acceptable stability were also achieved. The outstanding performance can be ascribed to the abundant electrochemistry active sites, facilitative diffusion of the electrolyte, high electron transfer rate and reliable stability architecture. Therefore, the NiFe‐LDH nanosheets demonstrate potential application in non‐enzymatic sensory of glucose.     

Ni离子掺杂对CoAl双氢氧化物电化学电容的影响

CoAl LDHs with different molar ratio of Ni have been prepared by chemical co-precipitation method.XRD results show that these materials have layered structures.Electrochemical tests show that Co(Ni)Al LDHs as electrode material have typical capacitive properties in a wide voltage range of 0.0 to 0.6 V;Co(Ni)Al LDH(Ni∶Co =4∶6)as an electrode material has the highest capacitance of 960F·g^-1 and good cycling performance.But the poor capacitive properties of NiAl LDH electrode are showed in a narrow voltage range of 0.3 to 0.55 V.     

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.     

基于主-客体相互作用的插层水滑石光敏特性研究

本文基于水滑石类插层材料(LDHs)特有的超分子结构及其功能可调控性,采用离子交换法成功合成了邻、间、对硝基苯甲酸阴离子(o-、m-、p-NBA-)插层的锌铝水滑石,并研究了插层产物的光敏性能。插层后这3种异构体化合物都在紫外光照射下表现出不同的光响应程度,即光敏作用:m-NBA-LDHo-NBA-LDH≈p-NBA-LDH。用PXRD、FTIR、UV/Vis和理论计算研究了光敏性能,并提出了可能的光敏机理,为其应用于新型感光材料提供了一定的理论基础。     

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。     

La~(3+)掺杂NiCo层状双金属氢氧化物纳米片的合成及其电化学性能

稀土离子La~(3+)掺杂的NiCo层状双金属氢氧化物纳米片具有高的超级电容器性能,比容量达到1115 F/g(1A/g)、倍率性能为517 F/g(30 A/g)。研究表明,La~(3+)离子掺杂不改变NiCo层状双金属氢氧化物晶体结构,但会显著影响其电子和离子传导特性,从而改变其电化学性能。根据离子电负性标度,La~(3+)(1.327)和Co~(2+)(1.377)离子的电负性值最接近,掺杂La~(3+)会优先取代Co~(2+)离子位置。由于La~(3+)离子的尺寸作用(106 pm),使得最优掺杂比例较小仅为0.26%,电化学结果表明较少的La~(3+)掺杂比例依然会显著调节NiCo层状双金属氢氧化物的电子/离子输运性质。     

层状氢氧化镁铝焙烧产物对SCN-的吸附性能

研究了层状氢氧化镁铝焙烧产物对SCN-的吸附行为,考察了焙烧温度、吸附温度、时间、pH值等因素对吸附的影响.在SCN-初始浓度为25 mg/L,温度为40℃,焙烧物投加量为2 g/L,pH值为6的条件下,4 h达到吸附平衡,SCN-脱除率可达96.91%.吸附过程符合Langmu ir等温方程式,主要是单分子层的吸热吸附.     

Glucose Biosensors Based on Electrodes Modified with Ferrocene Derivatives Intercalated into Mg/Al Layered Double Hydroxides

Two amperometric biosensors based on glassy carbon electrodes (GC) modified with Mg/Al layered double hydroxides (LDHs) containing ferrocene‐carboxylate (Fc? CO₂H) or ferrocene‐sulfonate (Fc? SO₃H), as interlayer anions, and glucose oxidase (GOx) are presented. Amperometric detection of glucose involves the electrochemical oxidation of H₂O₂ mediated by the ferrocene derivative. Optimization of the biosensors construction and of the operative conditions was investigated and is discussed herein. The performances of the two biosensors were evaluated by chronoamperometry, working at low anodic potentials (+0.400 V for Fc? CO₂H and +0.500 V for Fc? SO₃H vs. SCE). The linearity extended up to 1.5 mM and 10.0 mM in batch and in flow conditions, respectively, for both biosensors, whereas the sensitivity was higher for the one based on Fc? CO₂H (4.8±0.3 versus 2.0±0.3 μA mM^?1cm^?2 in batch mode, and 63.9±0.4 versus 25.8±0.4 μA mM^?1cm^?2 in flow mode). The biosensors display rapid response time (less than 20 s), good reproducibility, as well as good operational stability. Glucose can be accurately determined in the presence of the most common interferences that coexist in blood serum if an oxidative membrane containing nanoparticles of MnO₂ is applied on the biosensors' surface.     

Mg-Al-NO_3层状双金属氢氧化物电性质研究

采用电泳法和电势滴定法测定出不同电解质（LiCl,NaCl和KCl）溶液中Mg-Al- NO_3层状双金属氢氧化物（Mg-Al-NO_3LDH）颗粒的ξ电位、等电点、永久电荷密 度以及零电荷点等电化学物理量，探讨了电解质、pH和样品化学组成对Mg-Al- NO_3LDH电性质的影响，研究发现一价阳离子Li~+,Na~+,K~+对Mg-Al-NO_3LDH颗粒 的等电点有影响，电荷点依次增大，而等电点依次降低。