Investigation of nitrogen and iron co-doped TiO 2 films synthesized in N 2 /CH 4 via pulsed laser deposition technique

Nitrogen and iron ions co-doped titania films have been synthesized by PLD technique in nitrogen/methane (N2/CH4) (5:1) media at 1 mbar. Most of the samples are XRD amorphous but a certain amount of crystalline rutile is detected by Raman measurements. The presence of rutile phase only and its low crystallinity degree can be caused by nitrogen doping of oxide matrix. The most intensive VIS absorption and the lowest band gap values are observed for 5% Fe2O3 or Fe3O4 titania films that are supported by the highest nitrogen amount on the surface. The strongest photocatalysts in process of dichromate reduction under either UV or VIS irradiation are shown to be the films obtained from 5% iron oxide in titania target and synthesized at 550 °C as a result of optimal content of Ti–N and Ti–O–Fe structural fragments as revealed by XPS. The presence of Fe3+ and Fe2+ surrounded by oxygen as well as Fe–N bonds is confirmed by XPS data.