In this article, hierarchical flower-like ZnO nanostructures with controlled morphology and dimensions have been synthesized by solution phase approach and functionalized by Au nanoparticles (AuNPs) with the combination of electrodeposition to explore novel applications. The photocatalytic activity and lithium storage capacity of these hybrid nanostructures have been investigated. It has been found that hybrid nanostructure combining the large specific surface area, stability and catalytic activity of small AuNPs, demonstrate the higher photocatalytic activity than that of pure ZnO. Furthermore, an initial discharge capacity of 1280 mA h g À1 and a reversible capacity over 392 mA h g À1 at the 50 cycles are achieved for the Au-ZnO hybrid nanostructure, which is found to be much better than that of any previously reported ZnO anodes. The improved lithium storage capacity and cycle life of the Au-ZnO electrode result from the Li activity of Au-ZnO phase. The photocatalytic and electrochemical activity of Au-ZnO hybrid nanostructures provide a new platform for energy storage, environmental remediation and photocatalysis applications.

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Reversible self-assembly of Keggin structure polyoxometalate (POM) nanoclusters into nanodisks, nanocones, and nanotubes is described. The surface of POM clusters was modified by organic surfactant through single-phase approach. By carefully controlling and varying clusters surrounding environment, all assemblies were found to reverse into each other. The different assemblies and their evolutions from each other were studied by scanning electron microscopy and optical microscopy while the inner structure was investigated by transmission electron microscopy. The formation and transformation of different assembly shapes into each other is interpreted by considering electrostatic binding of surfactant molecules with the POM cluster, number of surfactant molecules attached, and particular surrounding environment arising from the optimized mixed solvent.

Polyoxometalates (POMs) are discrete anionic metal-oxide nanoclusters which exhibit unrivalled structural diversity, exceptional physical properties, and have many potential applications. Nonetheless, possessing high crystalline energy and hydrophilic nature, the assembly of POM clusters into rationally design architectures has been a long-standing bottleneck for their ultimate use in advanced materials and devices. To confront this challenge, both covalent and non-covalent modifications of POM nanoclusters are increasingly considered. This perspective reviews recent progress in the assembly of non-covalently modified surfactant-encapsulated POM nanoclusters with particular emphasis on our research work. The described solution-based assembly approach provides an excellent control on size, shape, and stability of the assembly structures. By effective exploitation of non-covalent interactions between the POM hybrid nanobuilding blocks, several unprecedented assembly structures including disks, cones, tubes, fullerene-like spheres, multiple shape flowers, wires, and thin films can be achieved. The assembly structures are highly robust and tunable in terms of size and shape and can act as hosts for guest nanomaterials to develop composite materials of combinatorial properties. In the last section of this manuscript, we present the catalytic properties of the assembly structures and their remote controlled manipulation in the reaction system.

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Size effects in the oriented-attachment (OA) growth process of Cu nanoseeds were found. Monodispersed Cu nanoseeds with average diameters of 2.2, 3.4, and 5.2 nm were controllably synthesized by the reduction of copper acetate in a boiling solvent and using dodecanethiol (DT) as a stabilizer and sulfur source of sulfide. These Cu nanoseeds were then treated under solvothermal conditions. When the diameters of Cu nanoseeds were smaller than 5 nm, Cu(2)S nanorods with lengths of approximately 30-100 nm and diameters of approximately 2-4 nm were obtained at lower temperatures, and Cu(2)S nanodisks with diameters of approximately 6-13 nm and thicknesses of approximately 2-4 nm were obtained at higher temperatures. Once the diameter of Cu nanoseeds was larger than 5 nm, only irregular particles were obtained, regardless of other conditions. The uniformity, which related to the density of DT on the surface of Cu nanoseeds, was the key for success of self-assembly of the final nanocrystals. High-resolution transmission electron microscopy images demonstrated that these nanorods, nanodisks, and particles were formed by an OA process of Cu nanoseeds into 1D, 2D, and 3D aggregates, which recrystallized into single crystals.

We present the polyoxometalate supramolecular nanobuilding blocks-based well-defined and robust rose, snowlike, and ice ball architectures by simple but effective exploitation of noncovalent interactions in the reaction system. All structures begin from the formation of disk assemblies that act as foundation for the construction of diverse, well-defined architectures. The rose, snow flowers, and ice balls, and the corresponding growth mechanisms are unambiguously demonstrated by collecting and analyzing intermediate morphologies. Different assembly shapes show interesting hydrophilic and hydrophobic surface properties which may provide opportunities to develop more suitable functional materials for different systems to overcome the polarity restrictions. All assemblies form through the precisely order and successive organization of polyoxometalate nanosupramolecules in a lamellar pattern that may be prompted or slowed-down by controlling ambient temperature of the reaction system. We expect the well-defined shape and the corresponding nano- and microspacing can act as hosts for foreign gust to develop new multifunctional materials.

A thin layer of gold nanoparticles (Au NPs) sputtered on cadmium sulfide quantum dots (CdS QDs) decorated anodic titanium dioxide nanotubes (TNTs) (Au/CdS QDs/TNTs) was fabricated and explored for the nonenzymatic detection of cholesterol and hydrogen peroxide (H 2 O 2 ). Morphological studies of the sensor revealed the formation of uniform nanotubes decorated with a homogeneously dispersed CdS QDs and Au NPs layer. The electrochemical measurements showed an enhanced electrocatalytic performance with a fast electron transfer (∼2 s) between the redox centers of each analyte and electrode surface. The hybrid nanostructure (Au/CdS QDs/TNTs) electrode exhibited about a 6fold increase in sensitivity for both cholesterol (10,790 μA mM −1 cm −2 ) and H 2 O 2 (78,833 μA mM −1 cm −2 ) in analyses compared to the pristine samples. The hybrid electrode utilized different operational potentials for both analytes, which may lead to a voltage-switchable dual-analyte biosensor with a higher selectivity. The biosensor also demonstrated a good reproducibility, thermal stability, and increased shelf life. In addition, the clinical significance of the biosensor was tested for cholesterol and H 2 O 2 in real blood samples, which showed maximum relative standard deviations of 1.8 and 2.3%, respectively. These results indicate that a Au/CdS QDs/TNTs-based hybrid nanostructure is a promising choice for an enzyme-free biosensor due to its suitable band gap alignment and higher electrocatalytic activities.