Integration of Carbon Dots on Nanoflower Structured ZnCdS as a Cocatalyst for Photocatalytic Degradation

The application of catalysts is one of the most effective methods in the oil refining, chemical, medical, environmental protection, and other industries. In this work, carbon dots (CDs) were selected as an initiator and doped into the main catalyst, Zn(0.2)Cd(0.8)S, and a novel Zn(0.2)Cd(0.8)S@CD composite catalyst with a nanoflower structure was successfully obtained. The synthesized composites (Zn(0.2)Cd(0.8)S@CDs) were characterized by means of SEM, TEM, XRD, FT-IR, XPS, and UV-Vis DRS. Transient photocurrent response and Nyquist curve analysis further proved that the carrier separation efficiency of the composite catalyst was significantly improved. In addition, the photocatalytic activity of Zn(0.2)Cd(0.8)S@CDs for rhodamine B removal from aqueous solution was tested under visible-light irradiation. When the amount of Zn(0.2)Cd(0.8)S@CDs composite catalyst reached 50 mg, the degradation rate of rhodamine B was 79.35%. Finally, the photocatalytic degradation mechanism of the Zn(0.2)Cd(0.8)S@CDs complex was studied. CD doping enhances the adsorption capacity of Zn(0.2)Cd(0.8)S@CDs composite catalysts due to the increase in surface area, effectively inducing charge delocalization and enhancing the photocatalytic capacity. Zn(0.2)Cd(0.8)S@CDs composites with low cost and high carrier separation efficiency have broad application prospects in the photocatalytic degradation of dyes.