Direct Z-Scheme Structure g-C3N4-BiOI with Highly Efficient Visible-Light-Driven Photocatalytic Activity for Bacteria Inactivation

A series of direct Z-scheme g-C3N4-BiOI photocatalysts with different BiOI contents were constructed by in-situ depositing BiOI nanoplates on the surface of g-C3N4 nanosheets. Light absorption results indicated that the introduction of BiOI can improve the visible-light absorption of g-C3N4. By analyzing the transient photocurrent responses, electrochemical impedance and photoluminescence (PL) emission spectra, it was disclosed that g-C3N4-BiOI Z-scheme structure not only decreases the recombination rate of photogenerated charge carriers but also remains the electrons with higher reduction ability and holes with higher oxidizing ability. The results of photocatalytic disinfection of Escherichia coli (E. coli) under visible light irradiation indicated that g-C3N4-BiOI exhibits dramatically enhanced photocatalytic activity when compared to single g-C3N4 and BiOI. And the optimal loading amount of BiOI corresponding to the highest photocatalytic performance of g-C3N4-BiOI is 20 %. In addition, the radical trapping experiments indicated that O-.(2)- and h(+) are the main reactive species responsible for the disinfection of E. coli.