Assembly Of CdS Or CuS Nanoparticles On The Two-dimensional Graphene Scaffold And Their Photocatalytic Properties

A great revolution in science and technology was triggered by reporting that condensedmatter physicists Geim and Novoselov had prepared two dimensional (2D) sheets of carbonatom-graphene. GR has a two dimensional honeycomb crystal structure and physicochemicalproperties. A serious problem is that the single-layer sheets are unstable in solution andaggregate back to graphite gradually, which obstructs its applications seriously. Notably, mostworks so far reported that GR-based nanocomposites can enhance photoactivity ofphotocatalyst for the reason of the excellent electron conductivity of GR or the role of GR as areservoir in electron capture/transport, and the recombination of photoexcited electron-holepairs can be restrained at the same time. Our work is stacking a nanoscale building block onthe unique sheet of GR is a positive significance to graphene-based hybrid materials andnanotechnology in materials science. Our main works and results are given as follows:(1)The graphite oxide was prepared from nature graphite flakes by Hummers andHoffman method, after thermal exfoliation the graphene oxide sheets were prepared, thegraphene sheets were gotten from the exfoliated Graphene oxide which was prepared after theultra sonic Processing then reduced via chemistry method.(2)Graphene/CdS nanosheet composites have been fabricated via a one-pot and in situsynthesis route. The structure and morphological characteristics of the resulted materials werecharacterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and theother analytical instruments. Photocatalytic activities of the obtained samples were examinedby degrading tests of methylene blue (MB) in photochemical reactions instrument. The resultsshow that CdS nanparticles anchored uniformly on the surface of graphene and the size ofparticles was around90nm. graphene/CdS shows excellent photocatalytic performance for the degradation of MB with a maximum removal rate of91%under visible light irradiation in60min.(3)A series of copper sulphide nanocrystals/graphene nanocomposites (CuS/GR) withdifferent weight ratios of GR were fabricated via a one-step hydrothermal approach by usingdimethylsulfoxide (DMSO) as the source of sulfur and solvent. The as-prepared samples werestudied by X-ray diffraction (XRD), UV-vis diffuse reflectance spectra (DRS), transmissionscanning electron microscopy (TEM) and photoluminescence spectra (PL) are employed todetermine the properties of the samples. The results show that the CuS nanocrystals with anaverage size of16nm almost overspread on the GR graphene scaffold. The samples exhibitexcellent photocatalytic activities in degrading the methylene blue (MB) compared with pureCuS. This work shows that CuS/GR nanocomposites appear to be promising in dyewastewater treatment as Fenton-like reagents.