We investigated the synergistic effects of ozone evolution reaction (OZER) coupled with UV irradiation for degradation of O3-refractory micro-pollutants in electrochemical (E)-UV/O3 process. A SiOx heterojunction layer over-coated on Ni-Sb-SnO2 remarkably enhanced the OZER across a wide pH range (0.4–10). The exceptional OZER efficiency was harnessed in E-UV/O3 to increase degradation rates (by 2.5–3.5-fold) and mineralization efficiencies (by 1.3–3.9-fold) for 2,6-dinitrotoluene (DNT) compared to the sums under dark electrolysis and photolysis. Clarifying DNT degradation intermediates and reactive oxygen species elucidated the promoting mechanism within the reaction network of O3 transformation to ∙OH, the principal oxidant for the supreme performance at near-neutral pH. Applicability of E-UV/O3 was demonstrated by minuscule halate ion generation, outstanding stability and energy efficiency, and elimination of N,N-diethyl-m-toluamide (DEET) in reverse osmosis concentrates (ROC). These comprehensive findings from mechanistic studies to real applications are expected to broaden the utilization of OZER-based water treatments.​