Synthesis of TiO2/g-C3N5 heterojunction for photocatalytic degradation of methylene blue wastewater under visible light irradiation: Mechanism analysis

TiO 2 /g-C 3 N 5 heterojunction is synthesized by the simple method, which is used in photocatalytic degradation methylene blue (MB) under visible light irradiation. The characterization analysis indicates that TiO 2 /g-C 3 N 5 has good crystallinity , and the heterojunction between TiO 2 and g-C 3 N 5 is formed with good MB photocatalytic degradation performance . The MB photocatalytic degradation removal of the TiO 2 /g-C 3 N 5 is 97.4 % at the concentration of 20 mg/L, which is significantly improved compared to the TiO 2 and g-C 3 N 5 . The visible light adsorption ability and the separation of photogenerated carriers of the TiO 2 /g-C 3 N 5 are improved, which is beneficial to the MB photocatalytic degradation. TiO 2 /g-C 3 N 5 has good reusability with 95.8 % of the initial removal after 5 cycles. The capture experiment and electron paramagnetic resonance spectroscopy analysis indicate that the existence of the h + , O 2 − and OH involves in MB photocatalytic degradation process . MB photocatalytic mechanism of the TiO 2 /g-C 3 N 5 is consistent with the direct Z scheme mechanism based on the band gap structure calculations.