Ternary nanostructure of CdS-rGO-Ag for enhanced photoelectrochemical application.

Abstract

In the present study, we have synthesized the ternary nanostructure of CdS-rGO-Ag by using the solvothermal method for the enhanced photocatalytic as well as electrocatalytic activity of the material. The optical properties of the prepared samples were characterized by using UV-visible spectroscopy and photoluminescence (PL) spectroscopy. A decline in the energy gap of CdS-rGO-Ag nanostructure to 1.90 ± 0.05 from 2.40 ± 0.08eV (CdS) is observed and may be attributed due to the rGO-Ag-induced creation of trap states in between the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels of CdS. The observed significant PL quenching also confirms the inclusion of trap states in the prepared nanostructure CdS-rGO-Ag, suggesting efficient photoactivity. The enhanced photocatalytic activity of CdS-rGO-Ag for methylene blue (MB) dye degradation supports the photocatalytic activity of prepared nanostructures. Furthermore, the photoelectrochemical catalytic activity of the CdS-rGO-Ag catalyst investigated by using cyclic voltammetry (CV), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS) depicts the improved current density, lowering of overpotential. The decrement in charge transfer resistance and enhancement in photocurrent density under light illumination indicates the better photoelectrochemical performance of CdS-rGO-Ag.