Construction of a flower-like microsphere g-C3N4/Bi2MoO6 S-scheme heterojunction for visible-light photocatalytic Cr(VI) reduction

A flower-like microsphere g-C3N4/Bi2MoO6 S-scheme heterojunction was successfully constructed, and its photocatalytic performance in the Cr(VI) reduction was investigated under visible light. The g-C3N4/Bi2MoO6 sample with a mass ratio of 10% showed the fastest reduction rate with a rate constant of 0.1203 min(-1), which was 9 and 5 times higher as compared with pure g-C3N4 and Bi2MoO6, respectively. Moreover, the g-C3N4/Bi2MoO6 sample exhibited excellent stability in the process of cyclic experiments. The photocurrent response and EIS analysis implied that the g-C3N4/Bi2MoO6 sample possessed a higher separation efficiency of photogenerated electron-hole pairs. Scavenger experiments and EPR measurements demonstrated that e(-) and & sdot;O-2(-) are the major reactive species in photocatalytic reduction of Cr(VI) for g-C3N4/Bi2MoO6 sample. The S-scheme heterojunction formation between the g-C3N4 and Bi2MoO6 promoted the separation of photogenerated charge carriers, thus forming more active species, which is the reason for the enhanced photocatalytic activity of the g-C3N4/Bi2MoO6 sample.