Construction of TiO2-Fe-C3N4 compound: Promotion of interfacial charge transfer effect through facile energy level alignment

Abstract

An efficient visible-light-driven photocatalyst with interfacial electron transfer (IFCT) effect was prepared by introducing a facile energy level alignment in heterostructured TiO2-Fe-C3N4, where IFCT was promoted strongly due to the effective electron transfer. The Fe (III) clusters grafted on the TiO2 microspheres, extended the photo response of TiO2 from UV to visible light region, resulting in better light absorption capability. What's more, the direct transfer of photoinduced electrons from TiO2/Fe to C3N4 was observed, which promoted the IFCT effect, leaving the high oxidizing holes in the valence band (VB) of TiO2 and conduction band (CB) of C3N4 for further degradation. The TiO2-Fe-C3N4 exhibited much better photocatalytic performance for methyl orange degradation and higher photocurrent under visible light irradiation than the bare TiO2 or C3N4, which was attributed to the synergistic effect between TiO2 and Fe/C3N4 as well as C3N4 and TiO2/Fe. In addition, the photo-induced holes in the VB of the TiO2 microspheres was confirmed by ESR analysis and a possible photocatalytic mechanism of TiO2-Fe-C3N4 composite under visible light irradiation was also proposed.