A simple route for the preparation of ZnS-reduced graphene oxide (RGO) composites via a one-pot hydrothermal synthesis is achieved. The chemical composition, morphology and structure of the ZnS-RGO samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N 2 adsorption-desorption specific surface area analysis (BET) and diffuse reflectance absorption (DRS). The results show that the ZnS nanoparticles were well dispersed on the RGO nanosheets which serve as the ZnS nanocrystal growth support and the morphology controller. It was found that the specific surface area of the ZnS-RGO composites increased with the incorporation of RGO. The ZnS-RGO composites were used as photocatalysts for the degradation of methylene blue (MB) under UV light irradiation. The results show the ZnS-RGO composites exhibited better photocatalytic activity and photodegradation kinetics compared with pure ZnS and commercial TiO 2 (P25) which is attributed to the high specific surface area and the hindrance of electron-hole pair recombination of ZnS due to the RGO incorporation. Therefore, the RGO has a positive effect on the ZnS-RGO composite as a photocatalyst.

The synthesis of carbon nanotubes (CNTs) has been proved to be greatly promoted by vapor metal catalysts, but the fast reaction feature and the required high-temperature environment involved in CNT evolution usually make it difficult for an insight into the evolution mechanism. Here, we successfully freeze the synthetic reaction at intermediary stages and observe the detailed morphologies and structures of the obtained intermediates and various objects related to carbon nanotubes. It is unveiled that there is a kindred evolution linkage among carbon nanoparticles, nanowires, and nanotubes in the vapor catalyst-involved synthetic processes: tiny carbon nanoparticles first form from a condensation of gaseous carbon species and then self-assemble into nanowires driven by an anisotropic interaction, and the nanowires finally develop into nanotubes, as a consequence of particle coalescence and structural crystallization. The function of metals is to promote the anisotropic interactions between the nanoparticles and the structural crystallization. An annealing transformation of carbon nanoparticles into nanotubes is also achieved, which gives further evidence for the evolution mechanism.

A green approach is developed for the reduction of graphene oxide (GO) via starch-based materials such as soluble starch, potato, sweet potato and corn powder. The graphene has been prepared via the starchbased materials at 80 C for 3 h. Atomic force microscopy and transmission electron microscopy results provide clear evidence for the formation of a few layers of graphene. X-ray photoelectron spectroscopy, the Fourier transform infrared spectra and Raman results indicate the partial removal of oxygencontaining functional groups from the surface of GO and formation of graphene with defects. The starch-based materials can not only act as the efficient reducing agents, but also play an important role in stabilizing the as-prepared rGO simultaneously. Besides, these starch-based materials are green, nontoxic and environmentally friendly compared with common reduction agents such as hydrazine. This new approach can open up a new possibility for prepared graphene in large-scale production with green and biological agents in mild synthesis condition.