Facile synthesis of C-decorated Fe,N co-doped TiO2 with enhanced visible-light photocatalytic activity by a novel co-precursor method

Lattice-doping and surface decoration are prospective routes to improve the visible-light photocatalytic ability of TiO₂, but the two techniques are difficult to combine into one preparation process because they are usually conducted under different conditions, which limits the efficiency of TiO₂ modification. In this study, TiO₂ was successfully modified by simultaneous lattice-doping and surface decoration, and the visible-light photocatalytic capacity was largely improved. Upon comparing the method reported here with previous ones, the most significant difference is that Fe(II)-phenanthroline was first used as the co-precursor of the introduced elements of C, N, and Fe. These three elements were simultaneously introduced to TiO₂ at high levels by this co-precursor method. The as-synthesized photocatalysts were systemically investigated and analyzed by several characterization methods such as XRD, FT-IR, XPS, Raman spectroscopy, EPR, UV-Vis DRS, photoluminescence spectra, photocurrent, electrochemical impedance spectra, TEM, and HRTEM. The photocatalytic degradation of 4-NP under visible-light irradiation was used to evaluate the photocatalytic activity of the photocatalysts. Based on the experimental data, a probable mechanism for the photocatalytic degradation by the photocatalysts is proposed. This is a novel method of using one source to simultaneously introduce metal and non-metal elements to TiO₂ at high levels, which may provide a new way to prepare highly effective TiO₂ photocatalysts.