Construction of a novel g-C3N4@Bi/BiOBr ternary heterojunction with Z-scheme mechanism for the efficient photocatalytic removal of ciprofloxacin

Photocatalysis can be a potential technique for decomposing antibiotics contaminants from water. In this study, g-C3N4 modified Bi/BiOBr nanosphere were prepared by a simple microwave solvothermal method, and the structure-properties relationships of the Z-scheme heterojunction were evaluated in degrading organic dyes. Various characterization techniques were then applied to elucidate the structure-performance relationships of the resulting heterojunction photocatalysts in degrading CIP. Compared with pristine g-C3N4 or Bi/BiOBr, the g-C3N4@Bi/BiOBr nanocomposites showed heightened property in photocatalytic degradation of CIP. The photocatalytic efficiency of CIP decomposition over the Z-scheme of g-C3N4@Bi/BiOBr heterojunction was about 2.38 and 1.35 times homologous to those of original g-C3N4 and Bi/BiOBr. The enhancement in photocatalytic activity of g-C3N4@Bi/BiOBr could be described by the Z-scheme pathway and the SPR effect of Bi0, which broadened visible light absorption and promoted the separation of photoinduced carriers. In addition, the effect of typical water matrix factors, such as pH, anionic, and cationic on photodegradation rate were evaluated. Furthermore, results of scavenging experiments showed that ·OH, ·O2−, and h+ all participate in the degradation of CIP. Based on the band structure and scavenging measurements, a possible photocatalytic mechanism for the as-synthesized g-C3N4@Bi/BiOBr composites was proposed.