Synthesis of Reduced Graphene Oxide/Copper Tin Sulfide (Cu2SnS3) Composite for the Photocatalytic Degradation of Tetracycline

Reduced graphene oxide (rGO)-copper tin sulfide (Cu₂SnS₃), (rGO-CTS), composites were successfully synthesized through a facile ex-situ process and the obtained composites were utilized as photocatalysts for the degradation of tetracycline (TCE) under a UV-LED irradiation. Physicochemical and morphological characterization of the composites confirmed the incorporation of CTS unto rGO. The optical study of the composites, using absorption spectroscopy, showed a red shift to lower energy with increase in the percentage of rGO in the composites. This reduction in band gap suggests a possible enhancement in photocatalytic potency due to enhanced charge carrier generation. The photocatalytic degradation study showed an increase in TCE degradation with increase in rGO content of the composite. This enhanced photocatalytic activity could be ascribed to: (i) enhanced adsorption properties due to the increased presence of oxygenated functional groups on rGO, and (ii) increased charge carrier generation and separation due to modification of the band edge potentials of the composites by the incorporation of rGO. Radical scavenging studies of the degradation process showed that photogenerated holes played the most significant role in the degradation process. A plausible mechanism was proposed for the degradation process based on the radical scavenging experiment and charge carrier characteristics of the catalyst.