Effectively enhanced photodegradation of Bisphenol A by in-situ g-C3N4-Zn/Bi2WO6 heterojunctions and mechanism study

In our work, a series of in-situ g-C3N4-Zn/Bi2WO6 heterojunctions were synthesized by a two-step solvothermal method followed with calcination process, using dicyanamide as the precursor for g-C3N4. C3N4-Zn/BWO heterojunctions were of gossypine shape, and both C3N4 and Zn were finely distributed into BWO nanosheets, forming a hierarchical structure. C3N4-Zn/BWO with 2.0 g of precursor addition and calcined at 520 °C exhibited effectively enhanced photodegradation for typical organic contaminant BPA, degrading 93% within 120 min, and implied a maximum rate constant k of 0.0211 min-1, indicating synergistic effect of C3N4 and Zn components in C3N4-Zn/BWO heterojunction. The enhancement of photocatalysis was due to quick carriers' separations via Z-scheme system and enlarged specific surface area of as-synthesized C3N4-Zn/BWO heterojunction. Main reactive oxidation species were detected to be h+ and O2-, and nine intermediates were confirmed via anlysis of LC-MS/MS. This study provided an alternative strategy to design novel photocatalysts containing multicomponents for higher photocatalytic activity.