Graphene-wrapped titanium dioxide nanoflower composites (G-TiO 2 ) consisting of nanosheets and nanoparticles were synthesized using a two-step solvo/hydrothermal process. Materials were characterized using SEM, TEM, high-resolution TEM (HRTEM), XRD, Raman spectroscopy, and FTIR.Further analysis was performed using Branauer-Emmett-Teller (BET) specific surface area analysis, electrochemical impedance spectroscopy (EIS), UV-Vis spectroscopy, and diffuse reflectance UV-Vis spectroscopy. Photocatalytic activity was determined by the photo-degradation of methylene blue under UV irradiation. Results show that the TiO 2 nanoflower exhibits a higher photocatalytic activity than commercial P25 by a factor of 1.49. This is attributed to the highly crystalline, hierarchical nature of the nanoflower structure, which provides improved charge transport and a reduced recombination rate of photo-generated electron-hole pairs. After wrapping with graphene, the G-TiO 2 composite can further improve the photocatalytic performance by providing a planar conjugated surface for dye adsorption, by further reducing recombination through accepting electrons from TiO 2 , and by causing a red shift in light absorption. The highest photocatalytic performance was found using a graphene loading of 5 wt%, which outperforms commercial P25 by a factor of 3.4.

Since its discovery, little work has been done on the vanadium chalcogenide VS 4 . Recently, a facile method for synthesizing VS 4 was discovered using a graphitic template. Here we show for the first time that template-free VS 4 can be synthesized in a hydrothermal reaction by controlling key parameters of the reaction: mainly time, temperature, and pH. The phase and morphology of VS 4 materials are tracked carefully using X-ray diffraction (XRD) and scanning electron microscopy (SEM) under each reaction condition. It is found that lower reaction temperatures and longer reaction times are sufficient to form VS 4 crystals, while variations in pH do not appear to greatly affect VS 4 crystallinity but rather surface area and morphology. By use of optimized reaction parameters, further characterization shows template-free VS 4 to be comparable with VS 4 templated with graphene oxide. Initial photocatalytic testing of these materials shows that VS 4 has the potential to be used in photocatalysis.

Hepatocellular carcinoma (HCC) is a malignant disease that is prevalent all around the world, especially in Asia. The combined detection of four common HCC markers, alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), carbohydrate antigen 125 (CA125) and 19-9 (CA19-9), can significantly improve the accuracy of early screening and diagnosis of this disease, which is very important for its effective treatment in a curable stage. In this article, hierarchical ZnO column arrays with core-shell structure were prepared, and specific antibodies of HCC markers were successfully conjugated onto ZnO arrays via the carbodiimide chemistry. The photoluminescence (PL) intensity of antibody-ZnO increased after HCC markers were bound. In the range of 0.5-15 ng/mL for AFP or CEA (or 0.5-15 U/mL for CA125 or CA19-9), the apparent linear relations between the PL enhancements and the concentrations of HCC markers offered simple standard curve for HCC detection in serum samples, indicating that the PL-enhanced antibody-ZnO arrays could be utilized in early clinical screening. A preliminary mechanism of PL intensity enhancement can be established based on this work.

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