The partially enlarged image in Figure 2b reveals that the CdS MPs were coated by graphene sheet clearly. Further evidence for the attachment of CdS MPs
onto the graphene is provided by TEM. Figure 2c shows a typical graphene nanosheet decorated by CdS MPs. It can be clearly observed that graphene nanosheets are hybridized with CdS MPs which are anchored on the graphene uniformly. Except for the CdS MPs decorating the graphene nanosheet, no other particles can be observed, which indicates the good combination of graphene and CdS MPs. The measurement of the size distribution shows that the CdS MPs in the hybrid have a relatively average diameter around 640 nm. For comparison, the TEM image of pure CdS MPs is shown in Figure 2d, which gives similar size distribution with that of CdS MPs in the hybrid. Figure 2 SEM and TEM images of G/M-CdS composites and pure CdS MPs. Typical SEM images of as-prepared G/M-CdS composites (a, b) and TEM images selleck chemical of G/M-CdS (c) and pure CdS MPs (d). The adsorption of Rh.B was enhanced gradually before 150 min in the dark, when the this website adsorption-desorption equilibrium was reached. Figure 3 shows the adsorption capacity of Rh.B onto G/M-CdS composites and
pure CdS MPs with different loading amount recorded at 150 min. The removal ratio of Rh.B increases with the increasing loading amount of G/M-CdS. The removal ratio of the dye is increased from 49.1% to 84.5% when the loading amount increases from 4 to 36 mg, which is higher than that of pure CdS MPs. The higher extraction efficiency of G/M-CdS could be attributed Amisulpride to the large surface area and high adsorption ability of the graphene. The mechanism of the G/CdS adsorption toward the organic dye may be derived from two reasons. One reason might be based
on van der Waals interactions occurring between the hexagonally arrayed carbon atoms in the graphite sheet of G/CdS and the aromatic backbones of the dye. The second reason might be due to the strong π-stacking interaction between the benzene ring of the dye and the large delocalized π-electron system of the G [37]. It can be seen that the removal ratio gets to saturation when the loading amount of G/M-CdS is more than 20 mg. Figure 3 Adsorption capacity of Rh.B onto G/M-CdS composites and pure CdS MPs with different loading amount. The photocatalytic performance of the G/M-CdS composites in terms of photodegradation of Rh.B molecules under visible-light irradiation was investigated. Figure 4 describes the removed Rh.B amount as a function of irradiation time. The loading amounts of G/M-CdS and CdS MPs are both 20 mg. When using G/M-CdS photocatalysts, the photodegradation rates of Rh.B had reached 69.5% after irradiating for 120 min. After the illumination time was extended to 270 min, 96.6% of Rh.B was decomposed. For pure CdS MPs, the photodegradation rate of Rh.B was 83.8% after 270 min visible light irradiation.