Combined internal and external electric fields to promote photocarriers separation of TiO2 homogenous S-scheme composite for CIP photodegradation

Abstract

The construction of internal and external electric fields is an effective collaborative way to boost the activity of photocatalyst. Herein, a face-to-face type of Fe-doped (FT) and Ag-loaded (AT) TiO2 ultra-thin nanosheet S-scheme composite (FT/AT (1:1)) has been synthesized for this aim. Introducing Fe3+ can extend light absorption and establish an internal electric field (IEF) inside TiO2. Combined with the external electric field (EEF) between FT and AT, photocarriers of the composite are efficiently separated according to the S-scheme way. EPR results indicate Ag can facilitate the oxygen reduction process so that the efficiently separated photogenerated electrons (e−) accumulated on Ag will generate lots of superoxide radicals (•O2−), while the photogenerated holes (h+) accumulated on the FT will oxidize water to generate vast hydroxyl radicals (•OH). Under the excellent generation efficiency of reactive oxygen species, FT/AT (1:1) plays a higher CIP photodegradation ability than FT and AT. This paper provides a simple and efficient preparation method of photocatalyst with IEF and EEF for water pollution remediation.