One-pot synthesis of CdxZn1−xS–reduced graphene oxide nanocomposites with improved photoelectrochemical performance for selective determination of Cu2+

Abstract

A series of Cd_xZn_1−xS–reduced graphene oxide (Cd_xZn_1−xS–rGO) nanocomposites were successfully prepared by a facile one-pot reaction. In this reaction system, H₂S gas acted as a sulfide source as well as a reducing agent, resulting in the formation of Cd_xZn_1−xS nanoparticles and simultaneous reduction of graphene oxide sheets to rGO. The photoelectrochemical (PEC) performances of Cd_xZn_1−xS–rGO nanocomposites were further investigated under visible irradiation, which showed that the photocurrent intensities were influenced by the cationic composition (x) in Cd_xZn_1−xS–rGO nanocomposites. Compared with other Cd_xZn_1−xS–rGO nanocomposites, the Cd_0.5Zn_0.5S–rGO nanocomposite displayed optimal photocurrent intensity, which was 5 times greater than that of CdS NPs. Based on Cu²⁺ selective suppression of the photocurrent intensity of the Cd_0.5Zn_0.5S–rGO nanocomposite, the photocurrent suppression obtained was linearly proportional to the logarithm of the concentration of Cu²⁺. The resulting Cu²⁺ photoelectrochemical sensor showed good performance including a wide linear range of 0.02 μM to 20 μM, low detection limit of 6.7 × 10⁻⁹ M (S/N = 3) and good anti-interference ability.