XPS investigation of carbon-doped TiO2 photocatalysts

In order to study the process of doping carbon into TiO2 without external carbon precursor, photocatalysts with different amount of doped carbon were prepared by heating the xerogel obtained by simple sol-gel method at different temperatures. After fitting and analyzing the peaks of XPS spectra of N 1s, C 1s, Ti 2p, O 1s, it is found that the variation trend of the amounts of doped carbon with temperature is in consistency with that of CO bond in samples. The amount of doped carbon in the sample calcined at 250 °C is the highest except that in xerogel. The variation of the relative amounts of CO bonds in samples can be well understood with the help of TG-DSC curves. It is inferred that the produced CO during calcination plays a very important role in carbon doping.