Hybrid sp3/sp2 Two-Dimensional Nanodiamonds for Electrochemical Ozone Production

Abstract

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