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Abstract: Polycarbazole (PCz) and PCz/chemically reduced graphene oxide (PCz/CRGO) modified glassy carbon electrodes (GCEs) were fabricated by a simple procedure and characterized. The modified electrodes based on PCz or PCz/CRGO were used as sensing electrodes for the voltammetric investigation of imidacloprid (IMI) insecticides. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used as sensing techniques. Both of modified electrodes have good electrocatalytic activity toward the reduction of IMI. The presence of CRGO enhanced the electrochemical signal of the modified glassy carbon electrode (GCE), which increased the sensitivity of the sensor. The limit of detection (LOD) and the limit of quantitation (LOQ) values for CV are 0.22μM and 0.74μM, respectively; while those values for DPV are 0.44μM and 1.52μM, respectively. [Copyright &y& Elsevier]

Mesoporous CuS nanospheres (CuS-NS) decorated reduced graphene oxide (rGO) aerogel composite (3D CuS-NS/rGO) was prepared by chemical reduction process and used for the synergistic removal of Cr(VI) and cationic dyes. The porosity of the as prepared samples was determined by Bruner-Emmet-Teller (BET) surface Area. Structural and morphological properties were studied by Scanning electron microscopy (SEM) and Transmission electron microscope (TEM). These analysis revealed that the as obtained hybrid CuS-NS/rGO composite with three dimensional (3D) structure was composed of mesoporous CuS nanospheres clearly induced onto the interconnected network of rGO sheets. The photocatalytic performance of 3D CuS-NS/rGO composites was studied against the reduction of Cr(VI) and degradation of cationic dyes (MB and RhB) under visible light spectrum. Excellent photocatalytic performance was observed with 3D CuS/rGO hybrid composites as compared to the as prepared CuS nanospheres. This high photocatalytic activity was attributed to the efficient charge transfer from the mesoporous CuS nanospheres to nanosheets of rGO, which was confirmed by UV–Vis spectrometry (UV–Vis). Electrical conductivity of the prepared samples was also investigated using electrochemical impedance spectroscopy (EIS). Additionally, the as prepared hybrid composites was easy to recycle by using simple tweezers and can be a best candidate for industrial applications. Image 1 • Preparation of 3D CuS/rGO aerogel by simple reduction process. • Photocatalytic activity of 3D CuS-NS/rGO investigated over Cr(VI) and cationic dyes. • Investigation of the catalyst concentration on photocatalytic performance. • High stability of 3D CuS-NS/rGO aerogel over five cycles. [ABSTRACT FROM AUTHOR]