Efficient photocatalytic performance of direct Z-scheme photocatalyst Bi3TaO7/Mn0.5Cd0.5S for levofloxacin degradation under visible light irradiation

The direct Z-scheme Bi3TaO7/Mn0.5Cd0.5S (MCS) composite photocatalyst was successfully constructed by an in-situ growth method. The performance for levofloxacin degradation by the composite catalysts under visible light irradiation was studied. The k value of BMCS-3 is the highest (0.05813 min−1), which is 3.1 times larger than that of BTO (0.01846 min−1) and 7.0 times larger than that of pure MCS (0.00825 min−1). The photocurrent (PC), photoluminescence (PL) spectroscopy and electrochemical impedance spectroscopy (EIS) suggested that the migration rate of photogenerated electrons and holes were greatly improved after the combination of Bi3TaO7 and Mn0.5Cd0.5S. On one hand, the separation efficiency of photogenerated electron-hole pairs of the composite material was improved due to the formation of Z-scheme heterojunction. On the other hand, the redox ability of photogenerated electron-hole pairs was maintained, which helped the composite material to exhibit enhanced photocatalytic performance. Meanwhile, the possible pathways of levofloxacin degradation and the toxicity of the produced intermediates were investigated.