A bio-electrochemical fuel cell reactor with cathodic Fe /TiO generates electricity. It destroys recalcitrant pollutants in cathode chamber without photocatalysis. Fe /TiO generates reactive oxygenated species in the dark or under photocatalysis. Cathodic produced ROS (hydroxy radical/superoxide radical) can degrade tetracycline or dyes. Electricity generation is enhanced by semiconductor catalyzed cathodic degradation of pollutants. In this study, a new water treatment system that couples (photo-) electrochemical catalysis (PEC or EC) in a microbial fuel cell (MFC) was configured using a stainless-steel (SS) cathode coated with Fe /TiO . We examined the destruction of methylene blue (MB) and tetracycline. Fe /TiO was prepared using a chemical reduction-deposition method and coated onto an SS wire mesh (500 mesh) using a sol technique. The anode generates electricity using microbes (bio-anode). Connected via wire and ohmic resistance, the system requires a short reaction time and operates at a low cost by effectively removing 94% MB (initial concentration 20 mg·L ) and 83% TOC/TOC under visible light illumination (50 W; 1.99 mW·cm for 120 min, MFC-PEC). The removal was similar even without light irradiation (MFC-EC). The of the MFC-PEC system was approximately 0.675 kWh·m ·order , whereas that of the MFC-EC system was zero. The system was able to remove 70% COD in tetracycline solution (initial tetracycline concentration 100 mg·L ) after 120 min of visible light illumination; without light, the removal was 15% lower. The destruction of MB and tetracycline in both traditional photocatalysis and photoelectrocatalysis systems was notably low. The electron spin-resonance spectroscopy (ESR) study demonstrated that ·OH was formed under visible light, and ·O was formed without light. The bio-electricity-activated O and ROS (reactive oxidizing species) generation by Fe /TiO effectively degraded the pollutants. This cathodic degradation improved the electricity generation by accepting and consuming more electrons from the bio-anode.