Novel dual-photoelectrode Z-scheme PEC system for efficient TBBPA removal and debromination: Performance and promoting mechanism

Abstract

Herein, a novel dual-photoelectrode Z-scheme photoelectrocatalytic system is created to achieve efficient synergistic anodic oxidation and cathodic reduction for TBBPA degradation and debromination. Based on the polydopamine-modified N-doped TiO2 nanotubes (PN-TNTs) photoanode and polydopamine-modified Cu2O nanowires (PC-CNWs) photocathode, the degradation, debromination and mineralization were 99.4%, 77.7% and 52.1% at 0.7 V under visible light for 2 h. The introduction of PDA enhances the visible light absorption by the TiO2 photoanode and protects the Cu2O photocathode from photocorrosion. The main active species identified by electron paramagnetic resonance (EPR) and scavenger experiments as •OH and e− were found to promote the degradation and debromination of TBBPA by oxidation and reduction, respectively. The degradation pathway of TBBPA was determined by Density Functional Theory (DFT) calculations and HPLC-MS analyses. Comparing the intermediates of single and dual chambers, it demonstrated that the photocathode was able to achieve the continuous debromination of TBBPA and intermediates, which reduced the toxicity. Finally, the stability, reusability and energy consumption were evaluated, confirming the feasibility of the system.