A facile way for one-pot synthesis of porous rose-like β-Bi2O3/Bi2O2CO3 with enhanced photocatalytic activity for BPA photodegradation

Various ratios of beta-Bi2O3/Bi2O2CO3 composites were successfully synthesized through solvothermal method which were characterized by XRD, UV-Vis DRS, SEM and XPS. The photocatalytic degradation of bisphenol A (BPA) demonstrated that both solvothermal and calcination temperatures significantly affected the photocatalytic activity of the prepared composites. The optimal photocatalytic performance was achieved at a solvothermal temperature of 180 degrees C and a calcination temperature of 300 degrees C under simulated sunlight irradiation with a 500 W xenon lamp. The characterization of the photocatalysts revealed that beta-Bi2O3/Bi2O2CO3 with diverse solvothermal temperatures exhibited a rose-like structure, and almost all materials possessed a wide absorption range from UV to visible light. A larger specific surface area is expected to provide more active sites and improve the photocatalytic activity of the materials. A narrower band gap would expedite the combination of e(-) and h(+) and inhibit the photocatalytic process. The high photocatalytic activity of beta-Bi2O3/Bi2O2CO3 is primarily attributed to the phase transition from Bi2O2CO3 to beta-Bi2O3. In addition, the active species were detected by ESR with DMPO as a trap, and simultaneous trapping experiments were performed. The comprehensive analysis suggested that both h(+) and center dot O-2(-) were the photocatalytically active species. The photocatalytic mechanism is proposed that the p-n heterojunction structure of beta-Bi2O3/Bi2O2CO3 accelerates the transfer of e(-) and h(+).