Exploring the visible light driven photocatalysis by reduced graphene oxide supported Ppy/CdS nanocomposites for the degradation of organic pollutants

Reduced Graphene oxide (rGO) supported polypyrrole/CdS nanocomposite (Ppy/CdS-NF) was prepared using facile chemical route. The synthesis of material was confirmed by characterization using advanced instrumentation techniques like XRD, FTIR, SEM-EDX and TEM. Thermal characteristic of nanocomposite was studied by TGA and DTA. Electrochemical Surface Area (ECSA) was calculated by Cyclic Voltammetry. The photocatalytic activities of the materials were demonstrated by degradation of Rhodamin B (Rh B), Reactive Blue-171(RB-171) dye and toluene under the influence of visible light irradiation. The photodegradation is attributed to efficient charge transfer between the composites thereby generating reactive oxygen species (ROS) which causes efficient photodegradation of the dye. Photoluminescence study confirmed the enhancement in photogenerated e(-) and h(+) pair separation and reduction in recombination rate. Quenching experiments was performed to determine reactive groups in the photodegradation and stability of nanocomposite was confirmed through recycling experiments. The composite of Ppy with CdS/rGO exhibited higher photodegradation efficiency over pure CdS-NF and Ppy which is attributed to the formation of more interfacial reaction sites between Ppy and CdS-NF. Further the mineralization of the degraded sample was also confirmed by monitoring the reduction of chemical oxygen demand as a function of time. Atomic Absorption Spectroscopy was used to detect the amount of Cd2+ ion and no significant amount of Cd2+ was detected in the degraded sample of dye.