Au@BSA prepared under alkaline conditions as an electrochemical non-enzymatic glucose sensor interface

Au@BSA was prepared at pH 8, pH 9, pH 10, pH 11, pH 11.4, and pH 12 as the working electrode of the non-enzymatic glucose sensor by biological template method. The six kinds of gold-cluster film working electrodes sintered by Au@BSA show golden color, especially the golden films corresponding to pH 8 and pH 12 are obvious. The gold-cluster films at pH 8, pH 9, pH 10, and pH 11 showed mono-layer gold nanoparticles, while the gold-cluster film at pH 11.4 showed porous structure. The gold-cluster film prepared at pH 12 presents a multi-layer 3D structure composed of a large number of gold nanoparticles. The linear detection range of the non-enzymatic glucose sensor prepared at pH 8 is the widest among the six sensors, and its sensitivity is also better than the other four sensors except the sensor prepared at pH 12. The sensor with the gold-cluster film-modified working electrode prepared at pH 12 show the highest sensitivity (330.002 μA mM^?1 cm^?2), because multi-layer 3D structure can bring more electric catalytic active site for this sensor. The electrochemical impedance spectroscopy showed that the specific surface area of the sensor prepared at pH 12 was much larger than that of the other five sensors. We provide a pH cycling method for once shaping preparation that can be extended to other metal films or metal-oxide films electrochemical interfaces. The Au@BSA non-enzymatic glucose sensor prepared in this paper is stable and can resist the toxicity of excessive chloride ions without losing activity.

     

Preparation of a Cu<Subscript>2</Subscript>O/rGO porous composite through a double-sacrificial-template method for non-enzymatic glucose detection

We report a double-sacrificial-template method for the fabrication of a Cu₂O and a reduced graphene oxide (rGO) porous nanocomposite (Cu₂O/rGO), which has great potential in non-enzymatic glucose detection. Firstly, an aqueous graphene oxide (GO) solution was dispersed in a polystyrene (PS)/cyclohexane (CH) solution to prepare a water-in-oil emulsion at 50 °C. Then, the emulsion was cast onto a glass substrate to evaporate solvents and cooled down to room temperature. During that time, the self-assembly of the GO sheets and the PS chains takes place at the interface. The cooling of the emulsion below the θ temperature of the system PS/CH (34.5 °C) facilitates the precipitation of the PS chains at the interface to form microcapsules. A sponge-like PS/GO composite film was thus obtained after complete evaporation of solvents, where the water droplets in the emulsion served as the first sacrificial template. The PS/GO composite was loaded with copper compounds and was then carbonized to remove the second template of the polymer. In this manner, a free-standing porous nanocomposite of Cu₂O/rGO was fabricated, and its structure was carefully characterized. The composite was applied as the working electrode in order to take advantages of its porous microstructure, the conductivity of rGO, and the electrochemical performance of crystalline nano-Cu₂O. The electrochemical responses of the composite to glucose were evaluated at glucose concentration ranging from 20 to 1000 μM. The results evidence that the porous nanocomposite of Cu₂O/rGO exhibits fast and linear amperometric responses to glucose with excellent sensitivities. Moreover, the stability of the Cu₂O/rGO composite in the electrolyte solution and its selective response to glucose have been demonstrated to indicate its practical potential.     

沸石矿模板制备多孔炭及其电性能研究

为降低模板法制备多孔炭的成本,使用一种天然沸石矿为模板来制备多孔炭。利用XRD、N2吸附和循环伏安法研究多孔炭的物相组成、孔结构和电化学性能。研究表明,所制备多孔炭的比表面积仅为411m2/g,但富含中大孔,并具有较宽的孔径分布;在1mol/L的H2SO4溶液中,1mV/s的扫描速度下,多孔炭的比容量为185F/g,扫描速度增加到500mV/s,其比容量保持率高达72%,比在相同条件下,比表面积2322m2/g的商业微孔活性炭的容量保持率23%高得多,且保持了良好的扫描曲线。     

H3BO3对化学共沉淀法制备Sr4Al14O25∶Eu2+、Dy3+的影响

采用化学共沉淀法制备Sr4Al14O25∶Eu2+、Dy3+长余辉发光粉体.研究了H3BO3的加入对粉体的相组成,晶体结构,发光性能与长余辉特性的影响.结果表明,加入的H3BO3大部分不进入晶格,作为助熔剂有利于Sr4Al14O25相的形成,一小部分H3BO3进入晶格中取代Al3+离子并且对Sr4Al14O25∶Eu2+、Dy3+长余辉发光粉体的发光性能与长余辉特性都有显著的提高, 然而过量的H3BO3加入则会降低粉体的长余辉特性, 本实验所获得H3BO3合适的添加量为0.7mol.     

H3BO3对化学共沉淀法制备Sr4Al14O25：Eu^2＋、Dy^3＋的影响

采用化学共沉淀法制备Sr4Al14O25:Eu^2 、Dy^3 长余辉发光粉体。研究了H3BO3的加入对粉体的相组成，晶体结构，发光性能与长余辉特性的影响。结果表明．加入的H3BO3大部分不进入晶格．作为助熔剂有利于Sr4Al14O25相的形成．一小部分H3BO3进入晶格中取代Al^3 离子并且对Sr4Al14O25:Eu^2 、Dy^3 长余辉发光粉体的发光性能与长余辉特性都有显著的提高．然而过量的H3BO3加入则会降低粉体的长余辉特性．本实验所获得H3BO3合适的添加量为0．7mol。     

改性的沉淀法制备三氧化二钇粉体

以Y（NO3）3和NH4HCO3为原料,添加适量的表面活性剂（聚乙烯醇）和（NH4）2SO4,利用改性的沉淀法制备了Y2O3前驱体。对前驱体在不同温度下进行焙烧,成功制备了超细Y2O3纳米粉体。分别采用XRD、TEM和TG—DTA分析了不同温度下煅烧所得粉体的物相、形貌以及前驱体热分解特性。结果表明,前驱体在900℃下保温1．5h,得到的Y2O3粉体颗粒近球形,细小均匀,平均尺寸约为7nm,粒径分布极窄,并具有很好的分散性和流动性。     

化学沉淀法合成纳米Bi2O3粉末

以Bi(NO3)3 为原料,利用化学沉淀法合成Bi2O3 粉体,发现最佳的工艺条件为:反应温度为90℃,反应时间为 2h, Bi(NO3 )3 溶液的质量浓度为300g/L。XRD分析结果表明产物为α Bi2O3。TEM和激光粒度分析表明,Bi2O3 粉体粒径约为 60nm,颗粒呈球形, 且分布均匀。将 Bi2O3 粉体置于空气中 6个月后测试未见团聚现象。反应机理是液 液反应的进行,实现了纳米Bi2O3 的生成。     

An electrochemical sensor based on V2O5 nanoparticles for the detection of ciprofloxacin

This research constructed and utilized a screen-printed electrode (SPE) modified with V₂O₅ nanoparticles (NPs) (V₂O₅/SPE) employed in order to sensitively and selectively quantify ciprofloxacin with exceptional accuracy in the phosphate buffer solution (PBS) with the use of differential pulse voltammetry (DPV). Moreover, electrochemical properties of this new V₂O₅/SPE sensor have been examined using diverse characterization procedures. Very good V₂O₅/SPE electrochemical features offered sensitive ciprofloxacin voltammetric determination with the reduced limit of detection (LOD?=?0.01 µM) toward electrocatalytic oxidation of ciprofloxacin in comparison with the bare SPE. Finally, this new disposable sensor exhibited higher sensitivity and thus has been efficiently utilized to determine ciprofloxacin in the real samples.

     

草酸盐共沉淀法合成LiNi0.8Co0.1Mn0.1O2及电化学性能

采用草酸盐共沉淀法合成前驱体,然后经过氧化气氛高温焙烧制备了锂离子电池正极材料LiNi0.8Co0.1Mn0.1O2.用X射线衍射(XRD)、扫描电镜(SEM)和恒电流充放电技术研究了pH值、焙烧温度、焙烧时间和锂用量对材料结构、微观形貌及电化学性能的影响.草酸盐共沉淀-氧化焙烧合成LiNi0.8 Co0.1Mn0.1O2的工艺条件为:pH值为5.5,焙烧温度为800℃,焙烧时间为12h,Li/M摩尔比为1.05.所制备的LiNi0.8 Co0.1 Mn0.1 O2在0.5C倍率下的首次充放电比容量达到174.5mAh·g-1,循环20周容量保持率为88.5％.     

pH 值对共沉淀制备的LiCo1/3Ni1/3Mn1/3O2结构与电化学性能的影响

用在不同pH值下制备的共沉淀前驱体合成了LiCo1/3Ni1/3Mn1/3O2材料.用XRD、IR、ESEM、交流阻抗、充放电测试仪测试了pH值对材料结构和电化学性能的影响.结果表明在pH=11条件下合成的材料的层状结构特征和结晶度较好;pH值对材料颗粒的大小没有显著的影响,所有材料的粒径均在0.3～0.7μm 范围内;pH=11时合成的材料的放电比容量最高(达163.48mAh/g),循环性能最好,可能是由于此条件下合成的材料在电池充放电过程中电荷传递速率较快所致.     

pH值对共沉淀制备的LiCo1／3Ni1／3Mn1／3Oz结构与电化学性能的影响

用在不同PH值下制备的共沉淀前驱体合成了LiCo1/3Ni1／3Mn1/3O2材料。用XRD、IR、ESEM、交流阻抗、充放电测试仪测试了PH值对材料结构和电化学性能的影响。结果表明在pH=11条件下合成的材料的层状结构特征和结晶度较好；pH值对材料颗粒的大小没有显著的影响，所有材料的粒径均在0．3～0.7μm范围内；pH=11时合成的材料的放电比容量最高（达163．48mAh／g），循环性能最好，可能是由于此条件下合成的材料在电池充放电过程中电荷传递速率较快所致。     

Structural and electrochemical investigation of novel hybridized MnO2/V2O5 nanocomposites prepared by one-step microwave-assisted method for electrochemical supercapacitor application

Journal of Materials Science: Materials in Electronics - Pure V2O5 and MnO2/V2O5 hybrid nanocomposites were synthesized by microwave-assisted method for electrochemical supercapacitor application....     

Epitaxially Strained CeO2/Mn3O4 Nanocrystals as an Enhanced Antioxidant for Radioprotection

Nanomaterials with antioxidant properties are promising for treating reactive oxygen species (ROS)-related diseases. However, maintaining efficacy at low doses to minimize toxicity is a critical for clinical applications. Tuning the surface strain of metallic nanoparticles can enhance catalytic reactivity, which has rarely been demonstrated in metal oxide nanomaterials. Here, it is shown that inducing surface strains of CeO₂/Mn₃O₄ nanocrystals produces highly catalytic antioxidants that can protect tissue-resident stem cells from irradiation-induced ROS damage. Manganese ions deposited on the surface of cerium oxide (CeO₂) nanocrystals form strained layers of manganese oxide (Mn₃O₄) islands, increasing the number of oxygen vacancies. CeO₂/Mn₃O₄ nanocrystals show better catalytic activity than CeO₂ or Mn₃O₄ alone and can protect the regenerative capabilities of intestinal stem cells in an organoid model after a lethal dose of irradiation. A small amount of the nanocrystals prevents acute radiation syndrome and increases the survival rate of mice treated with a lethal dose of total body irradiation.     

原子层沉积氧化铝包覆层增强五氧化二钒多孔薄膜电化学循环稳定性

最近,包覆氧化物进行表面修饰的方法已成功应用于改善锂离子电池阴极材料的容量稳定性。本文中,我们通过V2O5溶胶结合提拉法制备了V2O5多孔薄膜,并利用原子层沉积法对其包覆Al2O3原子层。V2O5多孔薄膜的电化学性质受包覆层厚度的影响,我们研究了不同薄膜厚度下的修饰效果。结果显示,原子层沉积法包覆不同厚度Al2O3原子层对锂离子电池的循环稳定性都有所改善,经10个ALD包覆循环的样品表现出最好的修饰效果。在此基础上,我们讨论探索了包覆Al2O3对容量及稳定性增强的机理。     

Preparation of Fe2O3/Al composite powders by homogeneous precipitation method

The Fe₂O₃/Al composite powders were prepared by homogeneous precipitation method. The influence of the concentration of Fe²⁺ and the molar ratio of raw materials on the preparation of Fe₂O₃/Al composite powders were investigated. X-ray diffractometer, scanning electron microscope, Fourier transform infrared spectroscopy and differential thermal analysis were used to analyze the morphology and structure of the Fe₂O₃/Al composite powders. The results show that the content of iron oxide in the composite powders could be effectively controlled by adjusting the concentration of Fe²⁺ and the molar ratio of raw materials in the plating solution. The surface of Al particle was coated with a layer of thick and dense iron oxide. The core-shell Fe₂O₃/Al composite powders with Fe₂O₃ content of 14.1% were produced, the coating efficiency of Fe₂O₃ reaches more than 77%. The iron oxide, which coated on the surface of the aluminium particle is flower-like cluster structure, each flower-like cluster is constituted by nano-flaky iron oxide.     

Fe3O4 magnetic nanoparticles as peroxidase mimetics and their applications in H2O2 and glucose detection

Artificial enzyme mimetics are a current research interest because natural enzymes bear some serious disadvantages, such as their catalytic activity can be easily inhibited and they can be digested by proteases. A very recently study reported by Yan et al. has proven that Fe(3)O(4) magnetic nanoparticles (MNPs) exhibit an intrinsic enzyme mimetic activity similar to that found in natural peroxidases, though MNPs are usually thought to be biological and chemical inert (Gao, L. Z.; Zhuang, J.; Nie, L.; Zhang, J. B.; Zhang, Y.; Gu, N.; Wang, T. H.; Feng, J.; Yang, D. L.; Perrett, S.; Yan, X. Y. Nat. Nanotechnol. 2007, 2, 577-583). In the present work, we just make use of the novel properties of Fe(3)O(4) MNPs as peroxidase mimetics reported by Yan et al. to detect H(2)O(2). The Fe(3)O(4) MNPs were prepared via a coprecipitation method. The as-prepared Fe(3)O(4) MNPs were then used to catalyze the oxidation of a peroxidase substrate 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) diammonium salt (ABTS) by H(2)O(2) to the oxidized colored product (see eq 1) which provides a colorimetric detection of H(2)O(2). As low as 3 x 10(-6) mol/L H(2)O(2) could be detected with a linear range from 5 x 10(-6) to 1 x 10(-4) mol/L via our method. More importantly, a sensitive and selective method for glucose detection was developed using glucose oxidase (GOx) and the as-prepared Fe(3)O(4) MNPs. The detection platforms for H(2)O(2) and glucose developed in the present work not only further confirmed that the Fe(3)O(4) MNPs possess intrinsic peroxidase-like activity but also showed great potential applications in varieties of simple, robust, and easy-to-make analytical approaches in the future.