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

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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.