rGO-Bi2MoO6 heterostructure: synthesis, characterization and utilization as a visible light active photocatalyst for the degradation of tetracycline

This study reports the synthesis of rGO-Bi2MoO6 heterostructure via a simple yet cost effective hydrothermal route and its morphological and structural characterizations were analyzed through a multitude of techniques such as XRD, FTIR, XPS, Raman, UV-DRS, PL, EDX, FESEM and HRTEM. The HRTEM analysis of the prepared heterostructure indicated the high-dense growth of Bi2MoO6 nanorods on the sheets of reduced graphene oxide, indicating the successful formation of the heterostructure. The heterostructure was subsequently used for the photocatalytic degradation of tetracycline in the presence of visible light illumination. The degradation efficiency of nearly 88% was obtained for an initial tetracycline concentration of 5 mg/L at pH 8 and photocatalyst loading of 0.50 g/L in 180 min using the prepared heterostructure. The synthesized rGO-Bi2MoO6 heterostructure displayed enhanced degradation efficiency (88%) in comparison to the pure Bi2MoO6 nanorods (55%) under similar reaction conditions. The scavenger study was conducted to determine the role played by various reactive oxygen species in the degradation of the drug and revealed that electrons and superoxide anion radicals played a pivotal role. The synthesized rGO-Bi2MoO6 heterostructure showed good recyclability up to four cycles. The significant enhancement in the photocatalytic performance of rGO-Bi2MoO6 heterostructure could be assigned to the introduction of graphene which leads to more efficient harvesting of incident visible light, massive reduction in the recombination rates of the photogenerated charge carriers and better charge transportation across the heterostructure surface.