Visible-light-driven synergistic photocatalytic degradation of organic dyes in water using a GO/ZnO/PANI/MoS₂hybrid system

Abstract A ZnO–PANI–MoS 2 -@GO hybrid nanocomposite was successfully synthesized via a multi-step process involving redox polymerization, hydrothermal integration, and controlled thermal treatment. Comprehensive characterization confirmed the hybrid architecture, showing coexisting crystalline ZnO and MoS 2 phases embedded within an amorphous GO–PANI matrix, enhanced thermal stability, and broad optical absorption extending into the visible region with a reduced band gap of 2.75 eV. The synergistic photocatalytic degradation of methyl orange (MO) under visible-light illumination (80 W LED) was systematically evaluated. The nanocomposite exhibited excellent photocatalytic efficiency, achieving 97.5% degradation at pH 7 with an optimal catalyst loading of 0.05 g. Kinetic analysis revealed that the degradation followed a pseudo-first-order reaction (k = 0.0308 min − 1 , R 2  = 0.988), consistent with Langmuir–Hinshelwood-type surface reactions. LC–MS analysis confirmed the stepwise breakdown of MO into low-molecular-weight intermediates, highlighting the catalyst’s efficiency in dye mineralization. These findings demonstrate that the ZnO–GO–PANI–MoS 2 nanocomposite is a robust, visible-light-responsive photocatalyst with promising potential for environmental remediation applications.