High quality carbon nanodots (C-dots) with high purity were synthesized through a mild, one-step electrochemical approach, without the assistance of any chemicals but only pure water. This high productivity method makes the synthetic process of C-dots synthesis both economical as well as environment-friendly. The as prepared C-dots are predominantly multi-layer graphene oxide, with luminescence and high up-conversion photoluminescence (emission of light at shorter wavelengths than the excitation wavelength). Meanwhile, C-dots showed peroxidise mimetic function and visible-light-sensitive photocatalytic activity for methyl orange degradation. In addition, a novel photocatalyst (TiO(2)/C-dots) was obtained by combining C-dots with TiO(2) through an easy hydrothermal method. Remarkably, TiO(2)/C-dots exhibited an excellent visible-light photocatalytic activity.

No abstract

Large-scale and monodisperse colloidal carbon nanospheres (CNSs) were synthesized with the assistance of polyoxometalates (POMs) under hydrothermal conditions. The POMs could act not only as a catalyst to promote the glucose dehydration process, but also as a stabilizer to prevent the aggregation of CNSs. The products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier-transform infrared spectroscopy (FT-IR). The diameters of CNSs from 100 nm to 900 nm can be controlled by different acidic and oxidizing properties of POMs. This method was demonstrated to be simple, reliable and reproducible. The conversion yield of CNSs prepared with the addition of phosphomolybdic acid was up to 37%. Based on the experiment, the possible mechanism for CNSs formation was proposed. After modification of CNSs with cysteine, the samples were utilized as electrode materials for sensitive heavy metal ions detection. The detection limits for lead(II) and cadmium(II) were 1 Â 10 À8 M and 2 Â 10 À7 M, respectively. The results highlight the potential application of CNSs as electrode materials for biosensors and catalysis.

Cupric oxide and cuprous oxide micro‐/nanomaterials with well‐controlled sizes and morphologies have been synthesized via different crystal growth techniques. Structural and morphological characterizations of these copper oxide micro‐/nanomaterials were performed by X‐ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). After that, these copper oxide micro‐/nanomaterials were used as catalysts for a typical C‐N cross‐coupling reaction directly. The catalytic results showed that different copper oxide micro‐/nanomaterials had different catalytic activities in C‐N cross‐coupling reaction. The particle size of cupric oxide and the oxidation state of copper played vital roles in the catalytic process. Cupric oxide with small particle size has the best catalytic activity, while cupric oxide with different morphologies has almost the same yields and cuprous oxide has very poor yields. Further, the possible catalytic mechanism for copper oxide nanomaterials catalyzed cross‐coupling reaction was proposed. And the influence of particle size and oxidation state was carefully discussed. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

No abstract