Bi 2 O 2 CO 3 /Bi 2 O 2+x S 1-x S-scheme n-n heterojunction with boosted photocatalytic degradation for bisphenol A

Bisphenol A (BPA) is considered to be a typical endocrine-disrupting compounds (EDCs), and its widespread existence in nature is quite harmful to human and ecological environment. The S-scheme n-n heterojunction composite (Bi 2 O 2 CO 3 /Bi 2 O 2+x S 1-x ) was constructed via a facile two-step chemical precipitation method for the removal of BPA in water environment. The optimal composite catalyst exhibited outstanding catalytic activity for BPA, obtaining approximately 0.00724 min −1 degradation rate constant which was 6.77 and 3.37 times that of the pristine BOC (Bi 2 O 2 CO 3 ) and BOS (Bi 2 O 2+x S 1-x ), respectively. UV–Vis diffuse reflectance spectroscopy (UV–Vis DRS), valence band X-ray photoelectron spectroscopy (VB XPS), and Mott-Schottky (M-S) plots were used to analyze the band position of the catalysts, and it was found that the two semiconductors were n -type semiconductors and formed S-scheme heterojunction. Through radical trapping strategies and electron spin resonance (ESR) analysis, the results showed that the hole and superoxide radicals took a major part in the removal of BPA. According to the products detected through high performance liquid chromatography-mass spectrometer (HPLC-MS), two reaction pathways of BPA degradation were deduced.