Facile fabrication of mesoporosity driven N–TiO2@CS nanocomposites with enhanced visible light photocatalytic activity

Abstract

For the efficient utilization of visible light from solar light illumination, wormhole mesoporous N-doped TiO₂ modified with carbon and sulfur (abbreviated as N–TiO₂@CS nanocomposites) have been fabricated using a sol–gel auto-combustion method. The prepared samples under different calcination temperatures were thoroughly characterized by XRD, TEM, FTIR, BET Surface area, UV-Vis DRS, XPS and PL. It has been demonstrated that in N–TiO₂@CS nanocomposites, incorporated N in the crystal lattice of TiO₂ exist as N–Ti–O, sulfur exist as sulfate ions (S⁶⁺) on the TiO₂ surface and carbon species were modified on the surface of the photocatalyst. N-doping narrows the band gap and sulfate species on the surface of TiO₂ act as co-catalyst. Moreover, the presence of surface carbon species enhances visible light harvesting and stimulates to separate photo generated charge carriers, which makes the system more potential towards photocatalytic application. The photocatalytic activities of the as prepared catalyst were evaluated for phenol degradation under visible light irradiation. The higher photocatalytic activity of the N–TiO₂@CS nanocomposite calcined at 400 °C (STU400) is attributed to the synergistic combination of C, N and S atoms, the wormhole mesoporous frame with high surface area and high crystalline anatase phase of TiO₂. The overall photocatalytic activity and the proposed mechanism are further confirmed through PL spectra and trapping of hydroxyl radicals.