Efficient oxidation of ammonium to nitrogen gas via accelerated ClO• generation at TiO2/Ru-IrO2 bifacial electrode in a UV-driven photoelectrochemical system

•HOCl reacts with its UV irradiation products Cl• and •OH to generate ClO• at Ru-IrO2.•The Cl• and •OH generated at TiO2 accelerate the generation of ClO•.•TiO2/Ru-IrO2 (UV) system exhibited a synergistic effect on NH4+ oxidation.•The system achieved a TN removal rate of 98.4% in the actual wastewater treatment.