The photocatalytic activity of
the Fe and N co-doped TiO2 nanoparticles was found to be considerably higher than that of the mono-doped
counterparts. The differences in the photocatalytic activity of the prepared samples were discussed. It can be
inferred that the visible light absorption alone is not a sufficient criterion for the photocatalyst activity. The
efficient photocatalytic activity of the Fe and N co-doped TiO2 can be attributed to the co-operation of the Fe and
N dopants. The presence of nitrogen and iron resulted in extending the absorption to the visible region. Under
aerated conditions, Fe ions can considerably promote the photogenerated charge separation and consequently
decrease the recombination rate of electron-hole pairs. The optimum iron content for Fe and N co-doped TiO2
was determined as 0.5 wt%. Photocatalyst loading of 3 g L−1 and air flow rate of 200 mL/min were identified as
optimum reaction conditions for photocatalytic desulfurization of the model fuel.