Synthesis and characterization of nitrogen and phosphate codoped titanium dioxide with excellent visible–light photocatalytic activity

Visible–light active (N, P)-codoped TiO2 (NP-TiO2) nanoparticles are prepared by one step hydrothermal method and characterized by XPS, XRD, SEM, FT-IR and UV–vis spectrum. Based on the XPS analysis, the chemical state of N in TiO2 is identified as N–Ti–O in the anatase TiO2 lattice, while P exists in a pentavalent-oxidation state (P5+) or as PO43- group coordinating in TiO2. The result confirms that the doping of phosphate would affect the crystallite size and structure of anatase. UV–vis spectra demonstrates that NP-TiO2 could shift the absorption edge of titania to the visible–light region effectively, which could increase the visible–light photocatalytic activity. The total degradation of methylene blue (MB) and rhodamine B (RhB) is significantly faster on NP-TiO2 samples than that on N-doped and NS-codoped TiO2 under visible–light irradiation.

► (N, P)-codoped TiO2 powders are prepared by a one-step hydrothermal method.
► N doping results in the formation of O–Ti–N linkage in anatase.
► P exists in a pentavalent-oxidation state (P5+) or as PO43- group.
► The codoped samples show enhanced visible–light photocatalytic activity.