Simultaneous removal of BPA and Cr(VI) via a redox photoelectrocatalytic system based on 0D/3D BQD@TiO2 photoelectrode: New insight into the mechanism and synergistic effect

For effective treatment of wastewater, synergetic removal of organics and heavy metals is of practical importance. Herein, we constructed a synergistic photoelectrocatalytic (PEC) system based on advanced photoelectrodes to realize efficient removal of BPA and Cr(VI). A 0D BiVO4 quantum dots (BQDs) decorated 3D TiO2 photoelectrode (0D/3D BQD@TiO2) was designed with "Facet/Type-II" dual heterojunctions (TiO2 facet heterojunction and BiVO4/TiO2 heterojunction). Complete removal and fast kinetics were achieved for both BPA (0.18 min−1) and Cr(VI) (0.82 M−1 min−1). 1O2 and h+ were confirmed as the main role for BPA oxidation and Fukui index (f -) predicted the active sites of BPA molecule for 1O2 attack. Meanwhile, Cr(V) intermediate was determined through PMSO probing experiment. The practical application prospect was comprehensively evaluated via examining the removal in actual wastewater and influencing factors. Finally, we examined the reusability of this system and extend its application to various kinds of organics coexisting with Cr(VI).