In-situ synthesis of g-C3N4-P25 TiO2 composite with enhanced visible light photoactivity

In situ synthesis method is used to synthesize g-C3N4-P25 composite photocatalysts with different mass rations. The experiment result shows that P25 particles with diameter at range of 20-30 nm were embedded homogenously in the sheets of g-C3N4. Coupling g-C3N4 with P25 can not only improve the visible light absorption, but also improve the visible light photocatalytic activity of P25. The g-C3N4-P25 nanocomposite has the higher photocatalytic activity than g-C3N4 under visible light. The optimal g-C3N4 content with the highest photocatalytic activity is determined to be 84 %, which is almost 3.3 times higher than that of individual g-C3N4 under the visible light. The enhanced visible light photocatalytic activity could be ascribed to the formation of g-C3N4 and TiO2 heteojunction, which results in an efficient separation and transfer of photo-induced charge carriers. The electron spin resonance results show that the O-center dot(2) -radicals are main active species for g-C3N4 and the g-C3N4-P25 nanocomposites.