Novel binary of g-C 3 N 4 coupling and Eu 3+ doping co-modifying bidirectional dendritic BiVO 4 heterojunctions with enhanced visible-light photocatalytic performance

The novel binary of g-C3N4 coupling and Eu3+ doping co-modifying bidirectional dendritic BiVO4 (Eu-CN-BVO) heterojunctions were synthesized via a solvothermal method. The synthesized samples were characterized by XRD, TEM, SEM, EDS-Mapping, HRTEM, XPS, FT-IR, UV–Vis DRS and PL. The optimized Eu-CN-BVO photocatalyst exhibited much higher photocatalytic efficiency, degrading 98% rhodamine B (RhB) in 50 min under visible light irradiation compared with BVO (59%), 5CN-BVO (84%) and 8Eu-BVO (65%) composites. The enhanced photocatalytic activity for Eu-CN-BVO was mainly attributed to heterojunction formation, the better optical absorption ability, the reduced band gap energy, the higher initial absorption rate and the reduced electron-hole pairs recombination. In addition, the trapping experiments confirmed that the action of three main active species were in the order of O2− > h+ > OH in photocatalytic degradation of RhB. And a possible photocatalytic mechanism was also proposed to illustrate the process of degradation. Recycling experiments presented that 8Eu-5CN-BVO heterojunction retained excellent photo-stability after five-time recycles.