Fenton-Assisted ZnIn2S4/C-PPy Cathode for Synergistic PVA Degradation and Photoelectrical Conversion in a Dual-Chamber Photocatalytic Fuel Cell

The simultaneous purification of polyvinyl alcohol (PVA) and photoelectrical conversion was achieved in a dual-chamber photocatalytic fuel cell (PFC) system, employing commercial P25 TiO 2 as the photoanode and a ZnIn 2 S 4 / carbonized polypyrrole (ZIS/C-PPy) composite as the cathode. ZIS microspheres and C-PPy nanowires were combined through simple mechanical mixing, forming a composite that enables directional electron transfer from C-PPy to ZIS under illumination, accompanied by a remarkably reduced charge-transfer resistance. The ZIS/C-PPy cathode promotes a 2-electron oxygen reduction pathway, generating H 2 O 2 , which further participates in a Fenton-like reaction in the presence of Fe 3+ to produce ·OH radicals. These reactive species, together with h + and ·O 2 - confirmed by quenching experiments and EPR analysis, synergistically enhance PVA degradation in both chambers while suppressing the competing hydrogen evolution reaction. As a result, the PFC system exhibits significantly improved degradation efficiency and photoelectrical conversion performance.