Enhanced Photocatalytic Performance of Semicrystalline Cl‐Doped <scp>PPy</scp>@<scp>TiO₂</scp> Nanocomposites for <scp>MB</scp> Degradation

ABSTRACT The application of photocatalysis for treating environmental pollution is gaining attention, focusing on improving the efficiency of photocatalysts. This study explores the sol–gel technique for producing titanium dioxide (TiO 2 ) in the anatase phase and shows that incorporating an optimal amount of polypyrrole (PPy) enhances its photocatalytic performance. Six PPy@TiO 2 samples with varying pyrrole concentrations (0–1.5 M%) were synthesized using in situ oxidative polymerization. The photocatalytic effectiveness was examined through the methylene blue (MB) degradation under low‐power ultraviolet radiation. Analysis techniques indicated the intimate attachment of PPy on TiO 2 particles, with X‐ray diffraction (XRD) analysis confirming a tetragonal anatase structure of TiO 2 . Photoluminescence studies showed that the synergetic effect of PPy and TiO 2 reduced the recombination of the generated electron–hole pairs, enhancing charge separation. Chloride (Cl − ) doping transformed the material from an amorphous to a semicrystalline structure, and adding an optimized 1.25 M% doped PPy to TiO 2 significantly enhanced its properties. This composite achieved 58.5% MB degradation within 30 min, which is 23.5% higher than that of TiO 2 alone. Additionally, this sample resulted in 96% dye degradation within 120 min, compared to 180 min for TiO 2 . These findings highlight the synergistic effect of TiO 2 and PPy in improving photocatalytic activity through midgap state formation and efficient charge separation.