Synthesis of rGO/TiO2/CdS Nanocomposites and its Enhanced Photoelectrochemical Performance in Determination of Parathion-Methyl

A photoelectrochemical (PEC) sensor for the determination of organophosphate pesticides (OPs) was developed based on rGO/TiO2/CdS photoactive nanomaterials. The rGO/TiO2/CdS nanocomposites were prepared by solvothermal method and electrochemical deposition technique successively. The morphologies and structures of the as-prepared nanocomposites were extensively investigated by SEM and XRD. In alkaline condition, p-nitrophenol as the hydrolysate of parathion-methyl (PM) could be obtained by a simple hydrolyzation process. Under optimal conditions, the rGO/TiO2/CdS NPs modified ITO electrode exhibited a good PEC performance toward the hydrolysate of PM. The photocurrent intensity was enhanced with the increase of the concentration of the hydrolysate of PM. The proposed PEC method could detect PM in the range from 0.05 nmol L-1 to 10 nmol L-1 with a detection limit of 0.02 nmol L-1 (S/N = 3). Thus, the excellent performance of the rGO/TiO2/CdS nanocomposites serve as the matrix of the sensor, which provides a new way for the fabrication of high-sensitivity PEC sensing system.