One-Pot Hydrothermal Synthesis of ZnO@Bi2MoO6-MoS2 Ternary Nanoflower Composites for Efficient Photodegradation of Rhodamine B

Abstract

Ternary heterojunction materials with well-aligned conduction (CB) and valence bands (VB) can significantly enhance photocatalytic performance. In this study, a ZnO@Bi₂MoO₆-MoS₂ (ZBM) nanoflower photocatalyst was synthesized using a one-pot hydrothermal method with urea, thiourea, and citric acid as reducing and stabilizing agents. The structure, morphology, and elemental composition of the ZBM composite were analyzed using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and energy-dispersive X-ray (EDX) spectroscopy. Electrochemical studies, including electron impedance spectroscopy (EIS) and photocurrent measurements, confirmed the material’s strong catalytic potential. Thermal analysis (TGA-DTA) showed that the ZBM composite is stable at high temperatures. The ZnO@Bi₂MoO₆-MoS₂ ternary composite exhibited excellent photocatalytic efficiency, degrading 97.2% of RhB in 60 min with a rate constant of 0.0219 min⁻¹ at neutral pH. It maintained structural integrity after four photodegradation cycles, demonstrating good stability. The optimal catalyst dosage for RhB degradation was determined to be 30 mg. The presence of ZnO and MoS₂ improved charge separation in Bi₂MoO₆, enhancing photocatalytic activity through dual Z-Scheme and S-Scheme mechanisms. Scavenging studies revealed that using peroxide as a scavenger, along with the ZBM photocatalyst, further improved degradation efficiency by increasing the involvement of reactive species such as holes and superoxide (O₂⁻).