Hybrid sp³/sp² Two-Dimensional\nNanodiamonds for Electrochemical Ozone Production

Abstract

Diamond electrodes have been receiving increased attention\nbecause\nof their favorable properties for wastewater treatment. However, the\nsurface properties of the diamond anode have not been fully determined.\nHerein, an extensive study was conducted to explore hybrid two-dimension\nnanodiamonds (2D NDs) with variable sp³/sp² ratios\nas metal-free electrochemical ozone production (EOP) electrocatalysts.\nThe 2D ND-1100 electrocatalyst with interface heterojunction of sp³/sp² exhibited outstanding EOP performance compared\nwith the normal ND@G with sp³@sp² core–shell\nstructure. Theoretical calculations further revealed that a high sp³/sp² ratio could effectively prohibit the O₂*/O₃* intermediate dissociation. O₃*\nwith five-ring configurations exhibited lower adsorption energies\nthan O₂* under the high sp³/sp² ratio\ncondition, indicating the high O₃ selectivity. The optimal\nsp³/sp² ratio was predicted to be 4:5 to 8:1\nfor O₃ selective formation. In addition, the 2D ND-1100\nelectrocatalyst demonstrated remarkable performance in electrodegrading\norganic pollutants, indicating its broad potential for efficient and\nadvanced oxidation applications. This work provides an effective strategy\nfor the removal of organic pollutants in wastewater based on high-performance\nhybrid two-dimension nanodiamonds with appropriate sp³/sp² rations.