Metalloporphyrins-sensitized titania-silica-iron oxide nanocomposites with high photocatalytic and bactericidal activities under visible light irradiation

Multifunctional photocatalyst system of meso-tetra(4-carboxyphenyl)porphyrin (TCPP) with different metal centers [Mn(II), Fe(III), Cu(II), Zn(II) and metal-free] adsorbed on titania-silica-iron oxide magnetic photocatalyst nanocomposites (TSI) that united superparamagnetic behavior and high photoactive activity under visible light irradiation have been prepared. The superparamagnetic nanocomposites have been characterized and analyzed using UV-visible absorption spectroscopy, X-ray diffractometry (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The results showed that copper(II)tetra(4-carboxyphenyl)porphyrin -sensitized titania-silica-iron oxide nanocomposites (CuTCPP-TSI) can effectively degrade methylene blue (MB) and kill Escherichia coli (E. coli) under irradiation with an incandescent lamp. The magnetic photocatalysts could be used at least four times without regeneration. Therefore, the CuTCPP-TSI nanocomposites can be applied in catalytic photodegradation and used for magnetically-guided antibacterial applications.