一维TiO2锐钛矿/金红石异相结的制备及光催化降解甲醛性能

TiO₂异相结主要通过高温方法制备,所制备材料的形貌和组成较难控制,尤其是在较低温度下一步制备一维TiO₂异相结仍具有一定的挑战性。采用简单、方便的一步水热法,在较低温度下(180℃)制备了一维纳米TiO₂异相结材料。X射线衍射(XRD)和高分辨透射电镜(HRTEM)分析表明,制备的材料以一维金红石相TiO₂纳米棒(长度：(400±50) nm,直径：(60±5) nm)为基本结构,粒径分布均匀的锐钛矿相TiO₂纳米粒子(直径：(9.5±0.5) nm)高密度、单分散地负载在纳米棒上。通过控制水热反应时间成功调控了异相结中锐钛矿相TiO₂的含量(20%～50%),进而实现了其光催化降解HCHO性能的调控。实验结果表明,当锐钛矿相TiO₂的含量为33%时(TiO₂-24,水热时间24 h制备的样品),异相结光催化剂表现出最佳的HCHO降解性能：在低光强LED灯(波长为365 nm,光强为12.26 mW·cm     

纳米TiO2-SnO2的制备及其对庚烷的气相光催化性能

纳米TiO2-SnO2的制备及其对庚烷的气相光催化性能;溶胶-凝胶;正庚烷;光催化降解     

Sensing properties of Pt@SnO2 core-shell nanocomposite detecting epinephrine

This proposed Pt@SnO₂ core-shell nanocomposite material based electrochemical sensor towards epinephrine detection showed high sensitivity, repeatability and high stability. It can play a significant role for precision determination of epinephrine in the drug sample and can also used for either simultaneous determination or others like acetaminophen (AC) and dopamine (DA) in samples.     

Application of Pt@SnO2 nanoparticles for hydrogen gas sensing

We report the fabrication of Pt@SnO₂ nanoparticles using a sol–gel method. These nanoparticles are used as a sensing material. The structural and morphological characterization of the prepared Pt@SnO₂ nanoparticles was performed using ultraviolet–visible spectroscopy, X‐ray diffraction, transmission electron microscopy, and energy‐dispersive X‐ray spectroscopy. The sensor responses of SnO₂ and 1 wt% Pt/SnO₂ to 1% hydrogen gas (H₂) were 1.3 and 1.9, respectively. The sensor response of a Pt@SnO₂ core–shell sensor increased to 5.1 at room temperature; it improved by 3.9 times compared to SnO₂ and by 2.7 times compared to 1% Pt/SnO₂ in sensing 1% H₂. The response time for the prepared Pt@SnO₂ sensor was also shortened by 2.0 and 1.4 times compared to SnO₂ and 1 wt% Pt/SnO₂, respectively. The sensor response increased rapidly from 1.4 to 5.1, with an increase in H₂ concentration from 800 to 10,000 ppm (1%). We investigated the H₂‐sensing mechanism of Pt@SnO₂.     

掺铈纳米TiO2薄膜制备及光催化降解甲醛甲苯

通过Sol-Gel工艺在玻璃表面及多孔陶瓷表面制得了均匀透明的掺铈纳米TiO2薄膜．通过SEM、XRD及UV-Vis等手段对玻璃表面掺铈纳米TiO2薄膜进行了表征．结果表明，薄膜表面无开裂现象、膜内部比表面积大、TiO2分布均匀．薄膜中出现的锐钛矿相在(101)面有一定的择优取向，且UV-Vis研究表明，掺铈纳米TiO2薄膜在近紫外的吸光度有明显提高．利用自行设计的反应器，以多孔陶瓷为介质，对甲醛、甲苯等有机物进行了光催化降解研究．结果表明，掺铈纳米TiO2薄膜对甲醛甲苯有极高的光催化降解效率，由于薄膜成本低廉，易于工业化，为净化室内空气开辟了新的途径．     

纳米SnO2的制备条件及其光催化活性

纳米粒子;光催化降解;纳米SnO2的制备条件及其光催化活性     

Synthesis and Photocatalytic Properties of Nano‐crystalline In2O3

A nano‐crystalline In₂O₃ was synthesized using calcinations methods and was used as a photocatalyst to degrade sulfan blue (SB) dye. In addition, this study addresses the conditions of the degradation and the factors that influenced the catalysis. In₂O₃ was prepared by calcining In(OH)₃ at heat ranges of 100–700 °C for 24 h. The In₂O₃ was characterized using field emission scanning electron microscopy (FE‐SEM), an X‐ray diffractometer (XRD), thermogravimetric analysis (TGA), and high‐resolution X‐ray photoelectron spectroscopy (HR‐XPS). The activities of these samples were tested for the photocatalytic degradation of SB dye. The results indicated that the In(OH)₃ that was calcined at 300 °C for 24 h had the best performance.     

Atom‐Precise Polyoxometalate–Ag2S Core–Shell Nanoparticles

Atomically precise polyoxometalate–Ag₂S core–shell nanoparticles were generated in a top‐down approach under solvothermal conditions and structurally confirmed by X‐ray single‐crystal diffraction as an interesting core–shell structure comprising an in situ generated Mo₆O₂₂^8? polyoxometalate core and a mango‐like Ag₅₈S₃₈ shell. This result demonstrates the possibility to integrate polyoxometalate and Ag₂S nanoparticles into a core–shell heteronanostructure with precisely controlled atomical compositions of both core and shell.     

TiO_2/SnO_2复合光催化剂的制备及光催化降解敌敌畏

以 Sn Cl4· Ti( OBu) 4、氨水、乙醇为原料 ,采用活性层包覆法 ,制备出 Ti O2 / Sn O2 复合光催化剂 ,并用IR、XRD、TEM和 BET等手段对样品进行了表征 .研究其对有机磷农药敌敌畏的光催化降解效果 ,与单一半导体催化剂 Sn O2 、Ti O2 做了简单对比 .结果表明 :所制 Ti O2 / Sn O2 样品为包覆型结构 ,由锐钛矿型 Ti O2 金红石型 Sn O2 组成 ,与 Sn O2 及 Ti O2 晶体粉末相比所制 Ti O2 / Sn O2 包覆粒子光催化活性得到明显提高 .     

Rationally Designed CeNP@MnMoS4 Core‐Shell Nanoparticles for Modulating Multiple Facets of Alzheimer's Disease

Alzheimer's disease (AD) is a complicated multifactorial syndrome. Lessons have been learned through failed clinical trials that targeting multiple key pathways of the AD pathogenesis is necessary to halt the disease progression. Here, we construct core‐shell nanoparticles (CeNP@MnMoS₄) targeting multiple key pathways of the AD pathogenesis, including elimination of toxic metal ions, decrease of oxidative stress, and promotion of neurite outgrowth. The SOD activity and copper removal capacity of CeNP@MnMoS₄‐n (n represents the number of layers of MnMoS₄, n=1–5) was investigated in vitro. We found that CeNP@MnMoS₄‐3 made an excellent balance between SOD activity and copper removal capacity. The effect of CeNP@MnMoS₄‐3 on Cu²⁺‐induced Aβ aggregation was studied by gel electrophoresis, transmission electron microscope (TEM), and atomic force microscopy (AFM). Compared with MnMoS₄ or CeNP alone, a synergistic effect was observed. Moreover, CeNP@MnMoS₄‐3 promoted neurite outgrowth in a dose‐dependent manner. Taken together, the results reported in this work show the potential of new multifunctional core‐shell nanoparticles as AD therapeutics.     

纳米TiO2 的制备及其光催化降解性能

采用低温水解沉淀法以TiCl4为原料制备了纳米TiO2,其结构经TEM和XRD表征。研究了太阳光激发下纳米TiO2对甲基橙的光催化降解性能,结果显示：纳米TiO2的分散性越好,粒径越小,光催化降解能力越强;以锐钛矿为主的复合纳米TiO2晶体比纯锐钛矿晶相具有更优异的光催化活性。     

掺铁TiO2纳米微粒的制备及光催化性能

铁掺杂;苯酚降解;掺铁TiO2纳米微粒的制备及光催化性能     

Zn0@ZnS Core‐Shell Nanoparticles via Oxidation of Intermediate Zn0 Nanoparticles

Zn⁰@ZnS core‐shell nanoparticles were prepared via reduction of ZnCl₂ to Zn⁰ nanoparticles and subsequent partial oxidation with elemental sulfur. The intermediate, highly reactive Zn⁰ nanoparticles were obtained by sodium naphthalenide ([NaNaph]) reduction of ZnCl₂ in tetrahydrofuran (THF). After centrifugation, the Zn⁰ nanoparticles were redispersed in a solution of sulfur in toluene and oxidized by subsequent heating to reflux. According to electron microscopy (HRTEM, HAADF‐STEM), the Zn⁰@ZnS core‐shell nanoparticles exhibit a mean outer diameter of 12 ± 4 nm, consisting of an inner Zn⁰ core (8 nm in diameter) and a ZnS shell (2 nm in diameter). HRTEM and XRD confirm the crystallinity of both core and shell. The Zn⁰@ZnS nanostructure shows synergistic properties of core and shell: the ZnS layer efficiently passivates the reactive Zn⁰ metal core against oxidation, whereas the optical properties point to dominating metallic behavior of the Zn⁰ metal core despite of the ZnS shell.     

Well‐Defined SiO2@P(EtOx‐stat‐EI) Core–Shell Hybrid Nanoparticles via Sol‐Gel Processes

Positively charged nanoparticles (NPs) are very interesting for biomedical and pharmaceutical applications, such as nonviral gene delivery. Here, the synthesis of SiO₂ nanoparticles with a covalently grafted poly(2‐ethyl‐2‐oxazoline) (PEtOx) shell (SiO₂@PEtOx) is presented. PEtOx with a degree of polymerization of 20 and 38 is synthesized via microwave supported cationic ring‐opening polymerization and subsequently end‐functionalized with a triethoxysilyl linker for subsequent grafting to silica particles with hydrodynamic radii of 7, 31, and 152 nm. The resulting SiO₂@PEtOx particles are characterized by using dynamic light scattering (DLS), transmission electron microscopy (TEM, cryoTEM), and scanning electron microscopy (SEM) to determine changes in particle size. Thermal gravimetrical analysis is used to quantify the amount of polymer on the silica surface. Subsequent in situ transformation of SiO₂@PEtOx particles into SiO₂@P(EtOx‐stat‐EI) (poly(2‐ethyl‐2‐oxazoline‐stat‐ethylene imine) grafted silica particles) under acidic conditions inverts the surface charge from negative to positive according to ζ‐potential measurements. The P(EtOx‐stat‐EI) shell could be used for the deposition of Au NP afterward.

     

Synthesis and Characterization of Dendrimer‐Encapsulated Bimetallic Core‐Shell PdPt Nanoparticles

Using a successive method, PAMAM dendrimer‐encapsulated bimetallic PdPt nanoparticles have been successfully prepared with core‐shell structures (Pd@Pt DENs). Evidenced by UV‐vis spectra, high resolution transmission electron microscopy, and X‐ray energy dispersive spectroscopy (EDS), the obtained Pd@Pt DENs are monodispersed and located inside the cavity of dendrimers, and they show a different structure from monometallic Pt or Pd and alloy PdPt DENs. The core‐shell structure of Pd@Pt DENs is further confirmed by infrared measurements with carbon monoxide (IR‐CO) probe. In order to prepare Pd@Pt DENs, a required Pd/Pt ratio of 1:2 is determined for the Pt shell to cover the Pd core completely. Finally, a mechanism for the formation of Pd@Pt DENs is proposed.     

Bioinspired Core–Shell Nanoparticles for Hydrophobic Drug Delivery

A large range of nanoparticles have been developed to encapsulate hydrophobic drugs. However, drug loading is usually less than 10 % or even 1 %. Now, core–shell nanoparticles are fabricated having exceptionally high drug loading up to 65 % (drug weight/the total weight of drug‐loaded nanoparticles) and high encapsulation efficiencies (>99 %) based on modular biomolecule templating. Bifunctional amphiphilic peptides are designed to not only stabilize hydrophobic drug nanoparticles but also induce biosilicification at the nanodrug particle surface thus forming drug‐core silica–shell nanocomposites. This platform technology is highly versatile for encapsulating various hydrophobic cargos. Furthermore, the high drug loading nanoparticles lead to better in vitro cytotoxic effects and in vivo suppression of tumor growth, highlighting the significance of using high drug‐loading nanoparticles.     

微波加热制备泡沫镍负载La3+掺杂纳米TiO2及其光催化降解甲醛的性能

 采用常规加热和微波加热方法制备了两种泡沫镍负载La3+掺杂的纳米TiO2光催化剂,以甲醛光催化降解为模型反应,考察了制备方法和掺杂La3+对催化剂催化性能的影响,并采用扫描电镜、透射电镜、 X射线衍射和能量分散式光谱分析对催化剂进行了表征. 结果表明,微波加热法制备的纳米TiO2具有典型的锐钛矿型晶体结构,其粒径均匀且明显小于常规加热法制备的催化剂. 泡沫镍负载1.5%La3+掺杂的TiO2的光催化性能得到明显改善,反应90 min后甲醛的降解率仍达到93%. 在实验中发现催化剂有失活现象,但经简单清洗后其活性能够恢复.     

Preparation of TiO2 Nanocrystals/Graphene Composite and Its Photocatalytic Performance

TiO2 nanocrystals/graphene （TiO2/GR） composite are prepared by combining flocculation and hydrothermal reduction technology using graphite oxide and TiO2 colloid as precursors. The obtained materials are examined by scanning electron microscopy, transition electron microscopy, X-ray diffraction, N2 adsorption desorption, and ultraviolet-visible diffuse spectroscopy. The results suggest that the presence of TiO2 nanocrystals with diameter of about 15 nm prevents GR nanosheets from agglomeration. Owing to the uniform distribution of TiO2 nanocrystals on the GR nanosheets, TiO2/GR composite exhibits stronger light absorption in the visible region, higher adsorption capacity to methylene blue and higher efficiency of charge separation and transportation compared with pure TiO2. Moreover, the TiO2/GR composite with a GR content of 30% shows higher photocatalytic removal efficiency of MB from water than that of pure TiO2 and commercial P25 under both UV and sunlight irradiation.     

Iron-Doped Titania Nanoparticles for the Photocatalytic Oxidative Degradation of Nitrite

Iron-doped titania nanoparticles exhibit a higher photocatalytic activity than pure TiO_2 for the degradation of nitrite. The optimum Fe-doped content in terms of activity is approximately 0.5％. The increase in photoactivity is probably due to the higher adsorption and the inhibition of electron-hole recombination. The photocatalytic oxidation reaction of nitrite over the Fe-doped TiO_2 catalyst follows zero-order kinetics, which is different from that over pure TiO_2. The reaction rate decreases linearly with the increase of the pH of the solution.