Preparation And Study Of MnO₂, Bi₂WO₆and Their Graphene-Based Nanocomposites

With the rapid development of the technology and culture, the need for advanced performance materials becomes very urgent. Researches on properties of advanced nanocomposites materials are becoming deeper and deeper. A number of high-performance MnO2,Bi2WO6and their composites were fabricated to achieve the appearance of environmental and electrical aspects, which also provides the possibility of to develope more advanced inorganic materials from packing techonology. Furthermore, graphene has been widely used in mechanical, electrical and photocatalytic fields. In this paper, we have prepared successfully MnO2and Bi2WO6inorganic nanomaterials, and their graphene-based nanocomposites have been prepared using the graphene as structure-directing agent. Finally, we analyzed and studied their performance in detail. The research contents and results are summarized as follows:1Investigation on the preparation and performance of MnO2and its nanocomposites.(1)We prepared α-MnO2rod-clusters nanomaterials using a different hydrothermal method, and the influencing factors (such as temperature and time) have been investigated in detail. The BET measurement indicated that the hydrothermal conditions have important effects on the surface area of the products. The mechanism of the adsorption has been confirmed to be physical adsorption using FT-IR technology. The formation mechanism of the products has been preliminary discussed. The MTT tests indicate that a-MnO2rod-clusters nanomaterials were non-toxic and environment friendly, which ensured the safety of these nanomateirals for potentional applications.(2)Preparation and antibacterial performance of Ag@MnO2nanomaterials.Flower-like Ag@MnO2microspheres have been prepared via hydrothermal and reduction methods. The products have been characterized through XRD, SEM and TEM technologies. The antibacterial activity tests indicated that Ag@MnO2nanomaterials have photocatalytic performance.(3) Core-Shell nanostructured water-soluble PAA@MnO2nanocomposites and their magnetic properties.PAA@MnO2nanocomposites have been prepared through a simple method under room temperature. The core-shell structure of the PAA@MnO2was characterized via SEM and TEM. The TGA and FT-IR spectra demonstrate that MnO2nanopartilces surfaces were successfully coated by PAA. And the growth mechanism has been proposed using on the experimental data. The PAA@MnO2nanocomposites exhibit characteristic magnetic properties, which show promising applications on drug transportation and liquid-phase fields.2The preparations and characterization of the GO, RGO and MnO2/RGOWe prepared the GO via a modified Hummer method with the graphite, H2SO4and nitrate as raw materials, KMnO4as oxidizing agent. The merit of this method was that KMnO4was replaced perchlorate to reduce the discharge of the toxicant gas. This method requires shorter reaction time compared with traditional routes. Oxidation degree of the product is high. The crystal structure is regular, facilitating swelling and peeling procedures.The products possessed rod-like structure, which could be used in the electrical and environmental fields.3Preparation and photocatalytic performance of the Bi2WO6/graphene nanocompositesBi2WO6/graphene nanocomposites have been obtained through a facile hydrothermal method. The photocatalytic performance for the RhB, Phenol and Cr(VI) have been studied in detail. We characterized the as-obtained products via a series of measurements, such as, XRD, SEM and TEM, and so on. We found that, with the increasing amount of GO, the reduced RGO can act as the template and structure-directing agents. A large number of Bi2WO6nanoparticles grow along the RGO nanosheets and then from fabricate the Bi2WO6/graphene nanocomposites. The energy gap of the Bi2WO6/graphene could be effectively reduced owing to the modification of RGO according to the DSR spectra. We then proposed the formation mechanism of the Bi2WO6/graphene basing on the experimental data. The photocatalytic performance of Bi2WO6/graphene nanocomposites has been enhanced through the modification of the RGO. The enhanced mechanism has been investigated and discussed in detail. This novel material could be applied in environmental field and the present methods provided a way to prepare other organic nanomaterials.