The electron transfer and the enhancement of H₂O₂ utilization efficiency at Cu-based Fenton catalyst-pollutant -water interface. 

　　Fenton reactions have been proven to be effective methods for eliminating the many recalcitrant organic pollutants in water due to the generation of hydroxyl radicals (^·OH). However, the low reaction rate and the excessive consumption of H₂O₂ limited the application of Fenton reactions to practical water treatment. In this present, mesoporous Cu^+/2+ -doped γ-Al₂O₃(γ-Cu-Al₂O₃) was prepared. The catalyst was found to be highly effective and stable for the degradation and mineralization of aromatic pollutants, and the high utilization efficiency of H₂O₂ was maintained at approximately 90% prior to the disappearance of the initial aromatic pollutants. In the reaction system, in addition to the unselective oxidation of ^·OH, H₂O₂ directly attacked the s-Cu²⁺-complexes aromatic ring with the phenolic OH group, which resulted in the formation of ^·OH and HO-adduct radicals that were oxidized to hydroxylation products by reduction of Cu²⁺ in the s-Cu²⁺-complexes to Cu⁺. The process prevented Cu²⁺ from oxidizing H₂O₂ to form HO₂^·/O₂^·− or O₂, which enhanced the Cu⁺/Cu²⁺ cycle, the formation of ^·OH and the utilization efficiency of H₂O₂. Meanwhile g-C₃N₄-CuCo-g-Al₂O₃ heterogeneous Fenton catalyst was prepared. It was found that the s-Cu - C₃N₄ complexes were formed by the phenolic OH group of hydroxylated g-C₃N₄ and the surface Cu，and the ^·OH was generated with the reaction of Cu⁺ and H₂O₂, the resulted Cu²⁺ was reduced to Cu⁺ by the p electron of aromatic ring of C₃N₄ from s-Cu²⁺- C₃N₄ complexes, meanwhile the resulted suface h⁺ of C₃N₄ reacted with H₂O forming ^·OH. Thus, it amounted to one H₂O₂ changing into 2 ^·OH. Therefore, the highutilization efficiency of H₂O₂ was more than 90% for degradation and mineralization of bisphenol A and so on most of refractory pollutants. Our findings present new Fenton catalytic mechanism for the first time, dealing with the key problem of Fenton technology for pratical application.

heterogeneous Fenton reaction mechanism of nano-Cu based catalyst