Oxygen Vacancy Associated Surface Fenton Chemistry: Surface Structure Dependent Hydroxyl Radicals Generation and Substrate Dependent Reactivity

TLDR

The chemistry of hydrogen peroxide decomposition and hydroxyl radical transformation at surfaces remains a major challenge for heterogeneous Fenton systems in chemistry, environmental, and life sciences. This study introduces a conceptual oxygen‑vacancy–associated surface Fenton system that operates without metal ion leaching and enables heterolytic H₂O₂ dissociation via electron‑donor oxygen vacancies. By precisely tuning the catalyst surface structure, the system allows facile control over the form of surface •OH, enabling targeted catalytic reactions with defined reactivity and selectivity. On BiOCl, •OH generated on the (001) surface diffuse into solution for selective oxidation of dissolved pollutants, whereas on the (010) surface they remain adsorbed and react preferentially with strongly adsorbed pollutants, thereby extending the scope of Fenton catalysts through surface engineering and consolidating fundamental Fenton reaction theories for environmental applications.

Abstract

Understanding the chemistry of hydrogen peroxide (H2O2) decomposition and hydroxyl radical (•OH) transformation on the surface molecular level is a great challenge for the application of heterogeneous Fenton system in the fields of chemistry, environmental, and life science. We report in this study a conceptual oxygen vacancy associated surface Fenton system without any metal ions leaching, exhibiting unprecedented surface chemistry based on the oxygen vacancy of electron-donor nature for heterolytic H2O2 dissociation. By controlling the delicate surface structure of catalyst, this novel Fenton system allows the facile tuning of •OH existing form for targeted catalytic reactions with controlled reactivity and selectivity. On the model catalyst of BiOCl, the generated •OH tend to diffuse away from the (001) surface for the selective oxidation of dissolved pollutants in solution, but prefer to stay on the (010) surface, reacting with strongly adsorbed pollutants with high priority. These findings will extend the scope of Fenton catalysts via surface engineering and consolidate the fundamental theories of Fenton reactions for wide environmental applications.