57 research outputs found
A General Synthetic Route Towards Highly Dispersed Metal Clusters Enabled by Poly ionic liquid s
The ability to synthesize a broad spectrum of metal clusters MCs with their size controllable on a subnanometer scale presents an enticing prospect for exploring nanosize dependent properties. Here we report an innovative design of a capping agent from a polytriazolium poly ionic liquid PIL in a vesicular form in solution that allows for crafting a variety of MCs including transition metals, noble metals, and their bimetallic alloy with precisely controlled sizes amp; 8764;1 nm and record high catalytic performance. The ultrastrong stabilization power is a result of an unusual synergy between the conventional binding sites in the heterocyclic cations in PIL and an in situ generated polycarbene structure induced simultaneously to the reduction reactio
Correction Three dimensional protein assemblies directed by orthogonal non covalent interactions
In this report, an orthogonal non covalent interaction strategy based on specific recognition between sugar and protein, and host guest interaction, was employed to construct artificial three dimensional 3D protein assemblies in the laborator
Spherical Polyelectrolyte Brushes Templated Hollow C MnO Nanospheres as Sulfur Host Materials for Li S Batteries
Li amp; 8722;S battery has been considered as the next generation energy storage device, which still suffers from the shuttle effect of lithium polysulfides LiPSs . In this work, mesoporous hollow carbon coated MnO nanospheres C MnO have been designed and synthesized using spherical polyelectrolyte brushes SPB as template, KMnO4 as MnO precursor, and polydopamine as carbon source to improve the electrochemical performance of Li amp; 8722;S battery. The hollow C MnO nanospheres enable the combination of physical confinement and chemical adsorption of the LiPSs. The thin carbon coating layer can provide good electrical conductivity and additional physical confinement to polysulfides. Moreover, the encapsulated MnO inside the carbon shell exhibits strong chemical adsorption to polysulfides. The constructed C MnO S cathode shows the discharge capacity of 1026 amp; 8197;mAh amp; 8201;g amp; 8722;1 at 0.1 amp; 8197;C with 79 capacity retention after 80 cycles. The synthesized hollow C MnO nanoparticles can work as highly efficient sulfur host materials, providing an effective solution to suppress the shuttle effect in Li amp; 8722;S batter
Efficient Sulfur Host Based on Yolk Shell Iron Oxide Sulfide Carbon Nanospindles for Lithium Sulfur Batteries
Numerous nanostructured materials have been reported as efficient sulfur hosts to suppress the problematic shuttling of lithium polysulfides LiPSs in lithium sulfur Li S batteries. However, direct comparison of these materials in their efficiency of suppressing LiPSs shuttling is challenging, owing to the structural and morphological differences between individual materials. This study introduces a simple route to synthesize a series of sulfur host materials with the same yolk shell nanospindle morphology but tunable compositions Fe3O4, FeS, or FeS2 , which allows for a systematic investigation into the specific effect of chemical composition on the electrochemical performances of Li S batteries. Among them, the S FeS2 C electrode exhibits the best performance and delivers an initial capacity of 877.6 mAh g 1 at 0.5 C with a retention ratio of 86.7 after 350 cycles. This approach can also be extended to the optimization of materials for other functionalities and application
Template synthesis of dual functional porous MoS2 nanoparticles with photothermal conversion and catalytic properties
Advanced catalysis triggered by photothermal conversion effects has aroused increasing interest due to its huge potential in environmental purification. In this work, we developed a novel approach to the fast degradation of 4 nitrophenol 4 Nip using porous MoS2 nanoparticles as catalysts, which integrate the intrinsic catalytic property of MoS2 with its photothermal conversion capability. Using assembled polystyrene b poly 2 vinylpyridine block copolymers as soft templates, various MoS2 particles were prepared, which exhibited tailored morphologies e.g., pomegranate like, hollow, and open porous structures . The photothermal conversion performance of these featured particles was compared under near infrared NIR light irradiation. Intriguingly, when these porous MoS2 particles were further employed as catalysts for the reduction of 4 Nip, the reaction rate constant was increased by a factor of 1.5 under NIR illumination. We attribute this catalytic enhancement to the open porous architecture and light to heat conversion performance of the MoS2 particles. This contribution offers new opportunities for efficient photothermal assisted catalysis
Trans synaptic assemblies link synaptic vesicles and neuroreceptors
Synaptic transmission is characterized by fast, tightly coupled processes and complex signaling pathways that require a precise protein organization, such as the previously reported nanodomain colocalization of pre and postsynaptic proteins. Here, we used cryo electron tomography to visualize synaptic complexes together with their native environment comprising interacting proteins and lipids on a 2 to 4 nm scale. Using template free detection and classification, we showed that tripartite trans synaptic assemblies subcolumns link synaptic vesicles to postsynaptic receptors and established that a particular displacement between directly interacting complexes characterizes subcolumns. Furthermore, we obtained de novo average structures of ionotropic glutamate receptors in their physiological composition, embedded in plasma membrane. These data support the hypothesis that synaptic function is carried by precisely organized trans synaptic units. It provides a framework for further exploration of synaptic and other large molecular assemblies that link different cells or cellular regions and may require weak or transient interactions to exert their functio
Colloidal dispersion of poly ionic liquid Cu composite particles for protective surface coating against SAR CoV 2
Herein, we report a waterproof anti SARS CoV 2 protective film prepared by spray coating of an aqueous colloidal dispersion of poly ionic liquid copper PIL Cu composite nanoparticles onto a substrate. The PIL dispersion was prepared by suspension polymerization of 3 dodecyl 1 vinylimdiazolium bromide in water at 70 C. The copper acetate salt was added into the PIL nanoparticle dispersion and in situ reduced into copper nanoparticles anchoring onto the PIL nanoparticles. Despite being waterborne, the PIL in bulk is intrinsically insoluble in water and the formed coating is stable in water. The formed surface coating by PIL copper composite nanoparticles was able to deactivate SARS CoV 2 virions by 90.0 in 30 minutes and thus may effectively prevent the spread of SARS CoV 2 through surface contact. This method may provide waterborne dispersions for a broad range of antivirus protective surface coatings for both outdoor and indoor application
Highly Dispersible Hexagonal Carbon MoS2 Carbon Nanoplates with Hollow Sandwich Structures for Supercapacitors
MoS2, a typical layered transition metal dichalcogenide is promising as an electrode material in supercapacitors. However, its low electrical conductivity could lead to limited capacitance when applied in electrochemical devices. Here, a new nanostructure made of hollow carbon MoS2 carbon was successfully synthesized by a L cysteine assisted hydrothermal method using gibbsite as a template and polydopamine as a carbon precursor. After calcination and etching of the gibbsite template, uniform hollow platelets, which are made of a sandwich like assembly of the partial graphitic carbon and the two dimensional layered MoS2 flakes, were obtained. The platelets showed excellent dispersibility and stability in water and good electrical conductivity due to the carbon provided by the calcination of the polydopamine coatings. The hollow nanoplate morphology of the material provided a high specific surface area of 543 m2 g, a total pore volume of 0.677 cm3 g and fairly small mesopores 5.3 nm . The material was applied in a symmetric supercapacitor and exhibited a specific capacitance of 248 F g 0.12 F cm2 at a constant current density of 0.1 A g, suggesting that the hollow carbon MoS2 carbon nanoplates are promising candidate materials for supercapacitor
Enhanced Catalytic Activity of Gold Polydopamine Nanoreactors with Multi compartment Structure Under NIR Irradiation
Photothermal conversion PTC nanostructures have great potential for applications in many fields and therefore they have attracted tremendous attention. However, the construction of a PTC nanoreactor with multi compartment structure to achieve the combination of unique chemical properties and structural feature is still challenging due to the synthetic difficulties. Herein, we designed and synthesized a catalytically active, PTC gold Au polydopamine PDA nanoreactors driven by infrared irradiation using assembled PS b P2VP nanosphere as soft template. The particles exhibit multi compartment structure which is revealed by 3D electron tomography ET characterization technique. They feature permeable shells with tunable shell thickness. Full kinetics for the reduction reaction of 4 nitrophenol has been investigated using these particles as nanoreactors and compared with other reported systems. Notably, a remarkable acceleration of the catalytic reaction upon near infrared NIR irradiation is demonstrated, which reveals for the first time the importance of the synergetic effect of photothermal conversion and complex inner structure to the kinetics of the catalytic reduction. The ease of synthesis and fresh insights into catalysis will promote a new platform for novel nanoreactor studie
Silver nanowires with optimized silica coating as versatile plasmonic resonators
Metal nanoparticles are the most frequently used nanostructures in plasmonics. However, besides nanoparticles, metal nanowires feature several advantages for applications. Their elongation offers a larger interaction volume, their resonances can reach higher quality factors, and their mode structure provides better coupling into integrated hybrid dielectric plasmonic circuits. It is crucial though, to control the distance of the wire to a supporting substrate, to another metal layer or to active materials with sub nanometer precision. A dielectric coating can be utilized for distance control, but it must not degrade the plasmonic properties. In this paper, we introduce a controlled synthesis and coating approach for silver nanowires to fulfill these demands. We synthesize and characterize silver nanowires of around 70 amp; 8201;nm in diameter. These nanowires are coated with nm sized silica shells using a modified Stöber method to achieve a homogeneous and smooth surface quality. We use transmission electron microscopy, dark field microscopy and electron energy loss spectroscopy to study morphology and plasmonic resonances of individual nanowires and quantify the influence of the silica coating. Thorough numerical simulations support the experimental findings showing that the coating does not deteriorate the plasmonic properties and thus introduce silver nanowires as usable building blocks for integrated hybrid plasmonic system
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