Nanocomposites of poly(1-naphthylamine)/SiO2 and poly(1-naphthylamine)/TiO2: Comparative photocatalytic activity evaluation towards methylene blue dye

The in situ polymerization of 1-naphthylamine monomer with silica (SiO₂) and titania (TiO₂) was adopted for the preparation of distinct poly 1-naphthylamine (PNA)/SiO₂ and PNA/TiO₂ nanocomposites. The absorption spectra of the nanocomposites showed a considerable red shift compared to pristine PNA which indicated the decrease in the orbital overlap between the π-electrons of the naphthyl rings with the lone pair of the nitrogen atom in the PNA molecules. The structural and the surface characterizations presented an effective interaction through the hydrogen bonding between imine (-NH) of PNA and hydroxyl (-OH) group of nanomaterials (SiO₂/TiO₂). The prepared nanocomposites showed a significant photocatalytic activity for the degradation of methylene blue (MB) dye under visible light illumination. It was found that MB dye degraded more efficiently by ∼60% over the surface of PNA/TiO₂ nanocomposites than PNA/SiO₂ (∼28%) and pristine PNA (9%) might due to the existence of high photogenerated ē-h⁺ pairs charge separation.