In water purification, the removal pathway of organic pollutants is crucial for catalyst design and reaction mechanism understanding. Traditionally, it was believed that catalytic oxidation reactions, such as Fenton and Fenton-like reactions, degrade and mineralize pollutants into CO₂ and H₂O. However, recent studies challenge this view, showing that organic pollutants can be removed through oxidative coupling and polymerization pathways on catalyst surfaces, known as the direct oxidative transfer process (DOTP). In heterogeneous catalytic oxidation systems using H₂O₂ and persulfate, catalysts like FeOCl and Co₃O₄ are considered Fenton-like. However, research shows that the primary reaction pathways for pollutant removal are not degradation and mineralization but coupling and polymerization. These pathways are widespread in various heterogeneous catalytic oxidation systems with different oxidants, catalysts, and reaction conditions. Thermodynamically, polymerization pathways are more feasible than mineralization pathways in weakly oxidizing environments. The significance of surface coupling and polymerization pathways in heterogeneous catalytic systems has been underestimated for nearly a century. The misunderstanding may stem from the imitation of homogeneous catalytic oxidation research methods and the difficulty in analyzing products and pathways in dilute solution systems. The polymerization pathway-based DOTP technology offers a promising direction for water purification, as it reduces oxidant/energy consumption and CO₂ emissions. However, catalyst deactivation may occur due to organic matter accumulation on solid surfaces. Future development of DOTP should focus on reducing catalyst costs and enhancing their accumulation capacity. The authors emphasize the importance of examining reaction pathways in catalytic oxidation systems.In water purification, the removal pathway of organic pollutants is crucial for catalyst design and reaction mechanism understanding. Traditionally, it was believed that catalytic oxidation reactions, such as Fenton and Fenton-like reactions, degrade and mineralize pollutants into CO₂ and H₂O. However, recent studies challenge this view, showing that organic pollutants can be removed through oxidative coupling and polymerization pathways on catalyst surfaces, known as the direct oxidative transfer process (DOTP). In heterogeneous catalytic oxidation systems using H₂O₂ and persulfate, catalysts like FeOCl and Co₃O₄ are considered Fenton-like. However, research shows that the primary reaction pathways for pollutant removal are not degradation and mineralization but coupling and polymerization. These pathways are widespread in various heterogeneous catalytic oxidation systems with different oxidants, catalysts, and reaction conditions. Thermodynamically, polymerization pathways are more feasible than mineralization pathways in weakly oxidizing environments. The significance of surface coupling and polymerization pathways in heterogeneous catalytic systems has been underestimated for nearly a century. The misunderstanding may stem from the imitation of homogeneous catalytic oxidation research methods and the difficulty in analyzing products and pathways in dilute solution systems. The polymerization pathway-based DOTP technology offers a promising direction for water purification, as it reduces oxidant/energy consumption and CO₂ emissions. However, catalyst deactivation may occur due to organic matter accumulation on solid surfaces. Future development of DOTP should focus on reducing catalyst costs and enhancing their accumulation capacity. The authors emphasize the importance of examining reaction pathways in catalytic oxidation systems.