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Three-dimensional (3D) TiO 2 architectures have attracted significant attention recently as they can improve the electrochemical stability and realize the full potential of TiO 2 -based anodes in lithium ion batteries. Here, flower-like rutile TiO 2 spheres with radially assembled nanorods (c-channels) were fabricated via a simple hydrothermal method. The 3D radial architecture affords massive active sites to fortify the lithium storage. Moreover, the presence of c-channels facilitates electrolyte infiltration and offers facile pathways for efficient Li + transport. As a result, this flower-like rutile TiO 2 anode gives significantly enhanced specific capacities (615 mA h g -1 at 1 C and 386 mA h g -1 at 2 C after 400 cycles) and a superior long-term cyclability (up to 10 000 cycles with a specific capacity of 67 mA h g -1 at 100 C). Kinetic analysis reveals that the enhanced diffusion-controlled and surface capacitive storage leads to the excellent electrochemical behavior. This work not only exhibits the enormous advantages of 3D architectures with c-channels, but also provides access to structural design and crystal phase selection for TiO 2 -based anode materials.

We report a detailed investigation of elementary catalytic decomposition of ammonia on the Pt-Ni-Pt(111) bimetallic surface using in situ near ambient pressure X-ray photoelectron spectroscopy. Under the near ambient pressure (0.6 mbar) reaction conditions, a different dehydrogenation pathway with a reduced activation energy barrier for recombinative nitrogen desorption on the Pt-Ni-Pt(111) bimetallic surface is observed. The unique surface catalytic activity is correlated with the downward shift of the Pt 5d band states induced by the Ni subsurface atoms via charge redistribution of the topmost Pt layer. Our results provide a practical understanding of the unique chemistry of bimetallic catalysts for facile ammonia decomposition under realistic reaction conditions.

We report a new capping-agent-free strategy for the synthesis of substrate-supported porous icosahedral Au nanoparticles (NPs) with rough naked surfaces, based on the crystallization from substrate-supported thin solution layers followed by solid-phase thermolysis. The plasmonic properties of icosahedral Au NPs have been studied using single particle dark-field scattering microscopy and spectroscopy. The two distinct localized surface plasmon resonance (LSPR) bands observed in the single particle dark-field spectra can be ascribed to the quadrupole resonance at ca. 425 nm and the size-dependent dipole resonance in the red region (645-708 nm). The unique rough naked surface, the facile synthesis, together with the ability to control the nanoparticle size and to vary the LSPR frequency in the red region, would make the substrate-supported porous icosahedral Au NPs promising on multiple levels in the applications of catalysis, ultrasensitive biosensors, and in surface-enhanced Raman scattering (SERS).

Gold nanorods with three different aspect ratios were prepared and their dual capabilities for two-photon imaging and two-photon photodynamic therapy have been demonstrated. These gold nanorods exhibit large two-photon absorption action cross-sections, about two orders of magnitude larger than small organic molecules, which makes them suitable for two-photon imaging. They can also effectively generate singlet oxygen under two-photon excitation, significantly higher than traditional photosensitizers such as Rose Bengal and Indocyanine Green. Such high singlet oxygen generation capability under two-photon excitation was ascribed to their large two-photon absorption cross-sections. Polyvinylpyrrolidone (PVP) coated gold nanorods displayed excellent biocompatibility and high cellular uptake efficiency. The two-photon photodynamic therapy effect and two-photon fluorescence imaging properties of PVP coated gold nanorods have been successfully demonstrated on HeLa cells in vitro using fluorescence microscopy and indirect XTT assay method. These gold nanorods thus hold great promise for imaging guided two-photon photodynamic therapy for the treatment of various malignant tumors.

Different from all reported sandwich molecular wires (SMWs), a novel class of SMW including vanadium boratabenzene (HBBz) clusters and their related one-dimensional (1D) SMWs are explored by using a density functional theory approach. The uniqueness of this class of SMWs lies in the boron heterocycles, where they possess a reactive functional atom. These features may overcome the limitation of existing SMWs which are inert and are difficult to be absorbed stably on surfaces. Theoretical calculations of the novel vanadium boratabenzene clusters indicated that they are energetically stable, with the rings having a restricted degree of rotation. In addition, its metallic 1D analog shows great promise in the applications of molecular electronics and spintronics.

Radially oriented anthracene nanowires and their self-assembled concentric ring arrays were prepared through a facial solvent-evaporation method. The successful growth of anthracene nanowires can be attributed to a combined mechanism of molecular self-assembly facilitated by strong π-π intermolecular interactions together with evaporation-induced capillary flow and fingering instability. Their radial orientation is determined by the capillary flow; their shape (either straight or curved nanowires) is governed by the competition between the capillary and Marangoni convectional flows. The self-assembly of nanowires into large-scale concentric ring arrays can be interpreted in terms of the repeated slipping-and-sticking motions of the contact line. The high-quality crystalline anthracene nanowire arrays exhibit size-dependent fluorescence emission with high-degree anisotropy.

A facile and simple approach for the covalent functionalization of surfactant wrapped graphene sheets is described. The approach involves functionalization of dispersible graphene sheets with various alkylazides and 11-azidoundecanoic acid proved the best azide for enhanced dispersibility. The functionalization was confirmed by infrared spectroscopy and scanning tunneling microscopy. The free carboxylic acid groups can bind to gold nanoparticles, which were introduced as markers for the reactive sites. The interaction between gold nanoparticles and the graphene sheets was followed by UV-vis spectroscopy. The gold nanoparticle-graphene composite was characterized by transmission electron microscopy and atomic force microscopy, demonstrating the uniform distribution of gold nanoparticles all over the surface. Our results open the possibility to control the functionalization on graphene in the construction of composite nanomaterials.