Activating Oxygen via the 3‐Electron Pathway to Hydroxyl Radical by La−O4 Single‐atom on WO3 for Water Purification

Abstract Shifting photocatalytic oxygen activation towards 3‐electron (e − ) pathway to hydroxyl radicals, instead of the normal 1 e − to superoxide radicals, becomes increasingly important for pollution degradation since hydroxyl radicals possess a high oxidation potential (2.80 V). Here, we demonstrate a selective oxygen activation to hydroxyl radicals via 3 e − pathway using single atomically dispersed La based on WO 3 fabricated with oxygen vacancies to weaken La−O coordination strength (denoted as LaO 4 −WO v ). Unsaturated‐state La overcomes the rate‐limited step of 2 e − oxygen reduction reaction towards to hydrogen peroxide via tuning binding free energy of key reaction intermediate *OOH, stepped by easy generation of hydroxyl radicals via 1 e − . This strategy alters the activation of oxygen process from 1 e − to 3 e − . Hydrogen peroxide and hydroxyl radicals over LaO 4 −WO v produces 3.8 and 3.3 mmol L −1 h −1 , 35 and 8 times that of detected over WO 3 , respectively. Rapid and complete removal of tetracycline realizes over LaO 4 −WO v with 0.077 min −1 of rate constant, 38 times that of WO 3 . Degradation efficiencies keep greater than 98 % following five repeats, revealing a practical‐utilization‐level robust stability. This work builds an unsaturated‐state transition metal site for manipulating oxygen activation towards an effective water purification as a representative application.