模板法制备介孔VN纳米电极材料及其电容性能

以十六烷基三甲基溴化铵(CTAB)为模板剂, 通过高温氨解还原V₂O₅前驱体制得了具有丰富介孔的VN纳米材料, 采用XRD与TEM分析观察样品的结构和形貌, 用N2吸附测试样品的比表面积和孔径分布. XRD分析表明, 介孔VN纳米材料属于立方晶系的晶体结构. TEM和N₂吸附测试结果表明, VN纳米材料的颗粒粒径大约为10 nm, 比表面积为88 m²/g, 有比较丰富的2~6 nm的介孔. 在1 mol/L KOH电解液中进行循环伏安和恒流充放电测试研究其电容性能, 结果显示, VN电极同时具有双电层电容性能和氧化–还原反应的准电容性能, 1 mV/s的扫描速率下能获得517 F/g的比电容; 当扫描速率增大到10 mV/s时, 其比电容仍有275 F/g.     

中孔炭的水玻璃模板法制备、结构调控及球形功能化

以廉价水玻璃为原料, 通过控制水解条件, 合成出具有不同尺寸的SiO₂溶胶, 并与间苯二酚-甲醛(RF)溶胶形成均相的凝胶复合物, 经常压干燥、炭化、酸洗, 得到具有可控结构的中孔炭材料。考察了水解温度、水解时间和反应物组成对孔结构的影响, 并通过氮气吸附、扫描电镜和透射电镜对材料的微观结构进行了表征。结果表明: 中孔炭的孔隙反相复制于SiO₂凝胶网络, 其平均孔径随水解时间的延长或水解温度的升高而增大, 并在6~12 nm范围内精细调控, 而其总孔隙率可以通过改变炭、SiO₂前驱体比例调节。对液相复合溶胶通过悬浮聚合法和喷雾干燥法处理, 分别制备出毫米级和微米级的中孔炭球, 进而实现了中孔炭在宏观形貌上的调控。本工作为中孔炭的低成本制备、精细结构调控以及球形功能化提供了重要参考。     

Facile Synthesis of Yolk–Shell‐Structured Triple‐Hybridized Periodic Mesoporous Organosilica Nanoparticles for Biomedicine

The synthesis of mesoporous nanoparticles with controllable structure and organic groups is important for their applications. In this work, yolk–shell‐structured periodic mesoporous organosilica (PMO) nanoparticles simultaneously incorporated with ethane‐, thioether‐, and benzene‐bridged moieties are successfully synthesized. The preparation of the triple‐hybridized PMOs is via a cetyltrimethylammonium bromide‐directed sol–gel process using mixed bridged silsesquioxanes as precursors and a following hydrothermal treatment. The yolk–shell‐structured triple‐hybridized PMO nanoparticles have large surface area (320 m² g^–1), ordered mesochannels (2.5 nm), large pore volume (0.59 cm³ g^–1), uniform and controllable diameter (88–380 nm), core size (22–110 nm), and shell thickness (13–45 nm). In vitro cytotoxicity, hemolysis assay, and histological studies demonstrate that the yolk–shell‐structured triple‐hybridized PMO nanoparticles have excellent biocompatibility. Moreover, the organic groups in the triple‐hybridized PMOs endow them with an ability for covalent connection of near‐infrared fluorescence dyes, a high hydrophobic drug loading capacity, and a glutathione‐responsive drug release property, which make them promising candidates for applications in bioimaging and drug delivery.     

Nonsacrificial Self‐Template Synthesis of Colloidal Magnetic Yolk–Shell Mesoporous Organosilicas for Efficient Oil/Water Interface Catalysis

Using interfacial reaction systems for biphasic catalytic reactions is attracting more and more attention due to their simple reaction process and low environmental pollution. Yolk–shell structured materials have broad applications in biomedicine, catalysis, and environmental remediation owing to their open channels and large space for guest molecules. Conventional methods to obtain yolk–shell mesoporous materials rely on costly and complex hard‐template strategies. In this study, a mild and convenient nonsacrificial self‐template strategy is developed to construct yolk–shell magnetic periodic mesoporous organosilica (YS‐mPMO) particles by using the unique swelling–deswelling property of low‐crosslinking density resorcinol formaldehyde (RF). The obtained YS‐mPMO microspheres possess an amphiphilic outer shell, high surface area (393 m² g^?1), uniform mesopores (2.58 nm), a tunable middle hollow space (50–156 nm), and high superparamagnetism (34.4–37.1 emu g^?1). By tuning the synthesis conditions, heterojunction structured yolk–shell Fe₃O₄@RF@void@PMO particles with different morphologies can be produced. Owing to the amphipathy of PMO framworks, the YS‐mPMO particles show great emulsion stabilization ability and recyclability under a magnetic field. YS‐mPMO microspheres with immobilized Au nanoparticles (≈3 nm) act as both solid emulsifier for dispersing styrene (St) in water and interface catalysts for selective conversion of St into styrene oxide with a high selectivity of 86%, and yields of over 97%.     

Template‐Free Fabrication of Mesoporous Alumina Nanospheres Using Post‐Synthesis Water‐Ethanol Treatment of Monodispersed Aluminium Glycerate Nanospheres for Molybdenum Adsorption

This work reports the template‐free fabrication of mesoporous Al₂O₃ nanospheres with greatly enhanced textural characteristics through a newly developed post‐synthesis “water‐ethanol” treatment of aluminium glycerate nanospheres followed by high temperature calcination. The proposed “water‐ethanol” treatment is highly advantageous as the resulting mesoporous Al₂O₃ nanospheres exhibit 2–4 times higher surface area (up to 251 m² g^?1), narrower pore size distribution, and significantly lower crystallization temperature than those obtained without any post‐synthesis treatment. To demonstrate the generality of the proposed strategy, a nearly identical post‐synthesis “water treatment” method is successfully used to prepare mesoporous monometallic (e.g., manganese oxide (MnO₂)) and bimetallic oxide (e.g., CuCo₂O₄ and MnCo₂O₄) nanospheres assembled of nanosheets or nanoplates with highly enhanced textural characteristics from the corresponding monometallic and bimetallic glycerate nanospheres, respectively. When evaluated as molybdenum (Mo) adsorbents for potential use in molybdenum‐99/technetium‐99m (⁹⁹Mo/^99mTc) generators, the treated mesoporous Al₂O₃ nanospheres display higher molybdenum adsorption performance than non‐treated Al₂O₃ nanospheres and commercial Al₂O₃, thereby suggesting the effectiveness of the proposed strategy for improving the functional performance of oxide materials. It is expected that the proposed method can be utilized to prepare other mesoporous metal oxides with enhanced textural characteristics and functional performance.     

Silica‐Templated Synthesis of Ordered Mesoporous Tungsten Carbide/Graphitic Carbon Composites with Nanocrystalline Walls and High Surface Areas via a Temperature‐Programmed Carburization Route

Ordered mesostructured tungsten carbide and graphitic carbon composites (WC/C) with nanocrystalline walls are fabricated for the first time by a temperature‐programmed carburization approach with phosphotungstic acid (PTA) as a precursor and mesoporous silica materials as hard templates. The mesostructure, crystal phase, and amount of deposited graphitic carbon can be conveniently tuned by controlling the silica template (SBA‐15 or KIT‐6), carburizing temperature (700–1000 °C), the PTA‐loading amount, and the carburizing atmosphere (CH₄ or a CH₄/H₂ mixture). A high level of deposited carbon is favorable for connecting and stabilizing the WC nanocrystallites to achieve high mesostructural regularity, as well as promoting the carburization reaction. Meanwhile, large pore sizes and high mesoporosity of the silica templates can promote WC‐phase formation. These novel, ordered, mesoporous WC/C nanocomposites with high surface areas (74–169 m² g^?1), large pore volumes (0.14–0.17 cm³ g^?1), narrow pore‐size distributions (centered at about 3 nm), and very good oxidation resistance (up to 750°C) have potential applications in fuel‐cell catalysts and nanodevices.     

New Triblock Copolymer Templates,PEO‐PB‐PEO,for the Synthesis of Titania Films with Controlled Mesopore Size,Wall Thickness,and Bimodal Porosity

The synthesis and properties of a series of new structure‐directing triblock copolymers with PEO‐PB‐PEO structure (PEO = poly(ethylene oxide) and PB = polybutadiene) and their application as superior pore‐templates for the preparation of mesoporous titania coatings are reported. Starting from either TiCl₄ or from preformed TiO₂ nanocrystalline building blocks, mesoporous crystalline titanium oxide films with a significant degree of mesoscopic ordered pores are derived, and the pore size can be controlled by the molecular mass of the template polymer. Moreover, the triblock copolymers form stable micelles already at very low concentration, i.e., prior to solvent evaporation during the evaporation‐induced self‐assembly process (EISA). Consequently, the thickness of pore walls can be controlled independently of pore size by changing the polymer‐to‐precursor ratio. Thus, unprecedented control of wall thickness in the structure of mesoporous oxide coatings is achieved. In addition, the micelle formation of the new template polymers is sufficiently distinct from that of typical commercial PPO‐PEO‐PPO polymers (Pluronics; PPO = poly(propylene oxide)), so that a combination of both polymers facilitates bimodal porosity via dual micelle templating.     

Mesoporous Metal–Metalloid Amorphous Alloys: The First Synthesis of Open 3D Mesoporous Ni‐B Amorphous Alloy Spheres via a Dual Chemical Reduction Method

Selective hydrogenation of nitriles is an industrially relevant synthetic route for the preparation of primary amines. Amorphous metal–boron alloys have a tunable, glass‐like structure that generates a high concentration of unsaturated metal surface atoms that serve as active sites in hydrogenation reactions. Here, a method to create nanoparticles composed of mesoporous 3D networks of amorphous nickel–boron (Ni‐B) alloy is reported. The hydrogenation of benzyl cyanide to β‐phenylethylamine is used as a model reaction to assess catalytic performance. The mesoporous Ni‐B alloy spheres have a turnover frequency value of 11.6 h^?1, which outperforms non‐porous Ni‐B spheres with the same composition. The bottom‐up synthesis of mesoporous transition metal–metalloid alloys expands the possible reactions that these metal architectures can perform while simultaneously incorporating more Earth‐abundant catalysts.     

新型两亲性嵌段共聚物导向合成有序大孔径介孔材料的研究进展

自从1992年首次报道介孔氧化硅分子筛M41S系列以来, 人们采用各种商业化表面活性剂为模板, 合成了多种骨架组成、丰富的有序介观结构、不同孔径尺寸的介孔材料, 并将其应用在能源、环境、催化等诸多领域。然而, 由于常规商业化模板剂的分子量大小有限, 合成的介孔材料具有较小的孔径(< 8.0 nm), 从而极大地限制了其面对大尺寸客体分子的相关应用。此外, 利用常规模板剂难以合成出具有晶化墙壁的介孔金属氧化物材料。近年来, 大分子量两亲性嵌段共聚物相继被报道用来合成新型介孔材料, 本文将综述基于这种嵌段共聚物为模板剂合成各种具有大孔径和晶化墙壁介孔材料的研究进展。