Synergistic effects of Co-doping on MoO₃ for enhanced photocatalytic degradation of chloramphenicol under visible light and its biocompatibility

In this study, we investigated the synergistic effects of cobalt (Co) doping on the catalytic performance of molybdenum trioxide (MoO₃) for the degradation of chloramphenicol (CAP) under visible light irradiation. Pure MoO₃ and Co/MoO₃ catalysts were synthesized using a hydrothermal method and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV–Vis diffuse reflectance spectroscopy (DRS), and Brunauer-Emmett-Teller (BET) analysis. The photo/electrochemical performance was analyzed using transient photocurrent and impedance measurements. The results revealed that Co-doping significantly enhances the visible light absorption and charge separation efficiency of MoO₃. The photocatalytic activity of the Co/MoO₃ was evaluated by monitoring the degradation of CAP in aqueous solution. The optimal Co-doping concentration was 4%, which exhibited the highest degradation efficiency, achieving up to 92% degradation of CAP within 30 min of visible light. The enhanced photocatalytic performance is attributed to the improved visible light absorption and reduced exciton recombination rates due to Co-doping. The degradation pathway was annotated using HPLC with UV-DAD detector and it confirmed complete CAP degradation. In-vivo toxicity assay confirmed that Co(4%)/MoO₃ nanoparticles do not induce inflammation and necrosis and do not alter primary organs weight in mice. These findings suggest that Co-doped MoO₃ as a promising photocatalyst for environmental remediation applications, particularly for degrading refractory organic pollutants under visible light.