Polypyrrole with Fe-Doped ZnO for Enhanced Photocatalytic Degradation of Methylene Blue

Polypyrrole (PPy) and its nanocomposites with Fe-doped ZnO (FZ) were synthesized via an in-situ polymerization method. The prepared materials were characterized using powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), photoluminescence (PL), and UV–Vis spectroscopy. PXRD results confirm that FZ and PPy/FZ composites (5PFZ, 10PFZ, and 15PFZ) exhibit crystalline nature, whereas PPy is amorphous. The optical properties were evaluated using UV–Vis and PL analyses. The photocatalytic performance was assessed through the degradation of methylene blue (MB) under visible light irradiation by varying parameters such as catalyst dosage, dye concentration, and pH. Among all samples, 10PFZ demonstrated the highest photocatalytic efficiency, achieving 97.81% degradation of MB within 180 min. Scavenger studies revealed that • 1pt OH , • 1pt O₂⁻ , and electrons (e–) are the dominant reactive species responsible for degradation, and the reaction follows a pseudo-first-order kinetic model.