The atmospheric pressure plasma enhanced nanoparticle synthesis (APPENS) process is applied to produce nitrogen (N) doped titania (TiO2) photocatalysts. With TTIP (titanium tetraisopropoxide; Ti(OC3H 7)4) and water vapors as precursors, the effect of plasma and annealing gas composition on the N-doping status is identified by a cross comparison of the chemical shift of N atoms with those of Ti and O atoms. The activities of various types of N-doped photocatalysts are evaluated via the conversion of isopropyl alcohol (IPA). The results show that the N-doped TiO2 particles with OX-Ti-NY and -(NO) dopants are produced via N2 plasma gas followed by air or N2 annealing gases. They have better visible and UV photocatalytic activities compared to the pure TiO2 photocatalysts prepared under O 2/Ar plasma and annealing gases. On the other hand, the N-doped TiO2 photocatalyst produced under N2/O2/Ar plasma gas and then annealed with pure N2 gas tends to have an additional dopant of -(NO2), but its photocatalytic activity is even worse than those of the pure TiO2 photocatalysts. The results reveal that the OX-Ti-NY and -(NO) dopants may have positive effects on the visible light photocatalytic activity while the -(NO2) dopant tends to have a negative effect on the visible light photocatalytic activity.