Engineering synergistic V_O-Co³⁺ pairs in CoOOH nanosheets for highly efficient and selective catalytic ozonation of...

The catalytic activation of O₃ on solid surfaces generates a spectrum of reactive oxygen species (ROS) with vastly different oxidative power. A central challenge lies in identifying surface sites that selectively produce highly oxidizing radicals over less reactive species, and in harnessing these potent ROS for efficient pollutant destruction. Here, we uncover a surface site dichotomy in cobalt oxides that governs O₃ activation selectivity in the photo-enhanced catalytic ozonation of dichloromethane (DCM). Using CoOOH, Co₃O₄, and CoO as a model system, we demonstrate that O₃ preferentially adsorbs at V_O, triggering electron transfer from the neighboring Co³⁺ to the adsorbed O₃. This electronic redistribution channels O₃ decomposition exclusively through a radical pathway (•O/•O₂^-). In sharp contrast, Co²⁺-rich surfaces lacking this V_O-Co³⁺ synergy favor an energy-transfer pathway yielding ¹O₂. The radical pathway confers a 3-fold higher DCM mineralization efficiency and a 34.7% lower O₃ consumption. The advantage of CoOOH in selective ROS generation applies equally to alkanes and aromatic compounds. This work establishes that pathway-selective activation reduces the O₃ demand, which in turn lowers the energy required for its generation.