A series of barbituric acid doped carbon nitride (CN-BA) photocatalysts were successfully prepared by copolymerizing dicyandiamide with barbituric acid (BA). Under AM1.5 simulated sunlight, CN-BA photocatalysts exhibit enhanced photocatalytic activity compared to pure carbon nitride for the degradation of aniline. The highest activity is obtained with 2% doped CN-BA photocatalyst. Results: on the photodegradation of aniline indicate that for the optimized CN-BA photocatalyst, the concentration of aniline solution was reduced gradually from 16 mg/L to 1.354 mg/L in 2 h. This corresponds to a 6 times higher photodegradation efficiency than pure carbon nitride samples. The enhanced photocatalytic activity of CN-BA relies on the enhanced surface area, the higher light absorption and the reduced recombination of the photo-generated electron-hole pairs. This interpretation results from multiple characterizations with EPR, BET, N-2 adsorption, Solid-state C-13 NMR, UV-vis DRS, FESEM, and TEM. Under simulated sunlight irradiation, CN-BA is excited and generates electron-hole pairs. The photo generated electrons in the CN-BA conduction band react with the molecular oxygen to form O-center dot(2)-. Part of the O-center dot(2)- transforms into (OH)-O-center dot, which further oxides aniline. Meanwhile, photo-generated holes in the valence band of CN-BA can benefit to the formation of (OH)-O-center dot or directly oxide aniline. (C) 2017 Published by Elsevier B.V.