Pesticides　and　its　degradation　products,　being　well–known　residues　in　soil,　have　recently　been　detected　in　many　water　bodies　as　pollutants　of　emerging　concerns,　and　thus　there　is　a　contemporary　demand　to　develop　viable　and　cost–effective　techniques　for　the　removal　of　related　organic　pollutants　in　aqueous　phases.　Herein,　a　visible−light−responsive　Fenton　system　was　constructed　with　iron–doped　bismuth　oxybromides　(Fe–BiOBr)　as　the　catalysts.　Taking　the　advantage　of　sustainable　Fe(III)/Fe(II)　conversion　and　optimized　H2O2　utilization,　the　optimal　Fe–BiOBr–2　catalyst　showed　an　excellent　atrazine　removal　efficiency　of　97.61%　in　120　min,　which　is　superior　than　the　traditional　homogeneous　Fenton　and　the　majority　of　heterogeneous　processes　documented　in　the　literature.　In　this　photo–Fenton　system,　hydroxyl　(·OH)　and　superoxide　(·O2–)　radicals　were　dominant　active　species　contributed　to　the　oxidative　degradation　of　atrazine.　Due　to　the　production　of　various　active　radicals,　five　degradation　pathways　were　proposed　based　on　the　identification　of　intermediates　and　degradation　products.　Overall,　this　work　not　only　demonstrates　a　fundamental　insight　into　creating　highly　efficient　and　atom　economic　photo−Fenton　systems,　but　also　provides　a　complementary　strategy　for　the　treatment　of　organic　pollutants　in　water.　©　2023