Interfacial bonded K-doped-C3N4@Bi2WO6 heterostructure for efficient photocatalytic degradation of tetracycline

Close interface contact and rapid electron directional transfer of heterojunction are key factors to promote the reaction activity and stability of photocatalyst, which play a critical role in the degradation of organic pollutants. Hence, a K-doped-C3N4@Bi2WO6 quantum dots heterostructure was successfully fabricated by an in-situ self-assembly strategy for photocatalytic degradation of tetracycline. The K-doped-C3N4 appears abundant N-defects and unsaturated coordination environment of carbon atoms around N defects. The C atoms around N defects bond with surface O atoms of Bi2WO6 quantum dots to form C-O bonds, which serve as a rapid migration pathway for photoexcited electrons and reduce the recombination of carriers, further promoting the photocatalyst stability. Moreover, Bi2WO6 quantum dots anchored on K-doped-C3N4 result in a Z-scheme heterojunction and realizes directional separation of electrons. The photoexcited holes in Bi2WO6 with high oxidation ability and photoexcited electrons in K-doped-C3N4 with high reduction ability are preserved for efficient tetracycline degradation. The optimized K-doped-C3N4@Bi2WO6 possesses a superior photocatalytic tetracycline degradation rate of 93 %, which is higher than pure C3N4 (40 %) and Bi2WO6 (48 %), respectively.