Enhanced acetaminophen degradation by photoelectro-persulfate system with 3D nanostructured PbO2/Sb-SnO2//blue-TiO2//WO3 bifacial photoanode and Mo-CuFeO2/CF cathode

Photoelectrocatalysis is a promising method for removing biorefractory organic pollutants. However, the inefficient utilization of light and electricity by photoanodes and the failure to effectively execute cathode functions typically lead to poor degradation performance. Therefore, in this study, a photoelectrocatalytic (PEC) system coupled with electro-activated persulfate (E-PS) was constructed using a 3D nanostructured PbO 2 /Sb-SnO 2 //blue-TiO 2 //WO 3 bifacial anode and a Mo-CuFeO 2 -modified carbon felt cathode. The results indicate that the bifacial anode could effectively implement electro-assisted photocatalysis on the irradiating side and electrocatalysis on the back side. This significantly accelerated acetaminophen degradation with a synergy index of 48.98 %. Additionally, the PEC/E-PS system was established by combining a bifacial anode with a persulfate-activated cathode, which promoted the efficient utilization of photogenerated electrons and increased the number of active species in the coupled system. Density functional theory calculations confirmed that Mo tended to dope the Fe sites and promote the adsorption of PS on Mo-CuFeO 2 , facilitating the continuous activation of persulfate. In the coupled system, the contribution order of different active species to acetaminophen degradation was h +  >  OH > SO 4 −  >  1 O 2  >  O 2 − . Their mutual conversion enabled the PEC/E-PS system to efficiently remove acetaminophen with a relatively high current efficiency (22.69 %) and low energy consumption (0.06 kWh⋅gCOD −1 ). The proposed PEC/E-PS system is an efficient and sustainable method for treating organic contaminants in wastewater.