Annealing temperature-dependent CdS phase tunability in improving photocatalytic efficiency towards aquatic dye decomposition

Abstract

Combinations of different materials can improve the functionality of a composite. Heterogeneous structures that consist of various crystalline phases in a single material may also improve the physical and catalytic properties. In this work, we have synthesized highly crystalline CdS with cubic, hexagonal, and heterogeneous phases through precipitation, followed by varying the annealing temperature. The photocatalytic degradation was performed on aqueous rhodamine 6G (R6G) dye as a model pollutant under UV irradiation. From the results, UV–Vis analysis revealed that the heterogeneous structure yields the most intense absorption with a reduced band gap, which is useful for improved photocatalytic reactions. The SEM image demonstrates that the heterogeneous CdS contains more tiny granule particles that disperse extensively over the surface. As a consequence, heterogeneous CdS shows enhanced photocatalytic degradation efficiency and rate constant, which may serve as a future photocatalyst for wastewater remediation.