Abstract
To investigate the impact of carbon phase conversion on the catalytic activity of nanodiamonds, in this study, we tested nanodiamonds subjected to graphitization at varying temperatures for persulfate activation. Temperatures beyond 1000°C (where only surface graphitization occurs) steadily enhanced the persulfate activation capability as the inner carbon underwent substantial sp3-to-sp2 transformation. Nanodiamonds annealed at 2000°C outperformed benchmark nanocarbons in terms of persulfate activation efficiency. Non-radical activation occurred primarily based on the effects of radical quenchers, oxidation product distribution, substrate-dependent reactivity, and electron paramagnetic resonance spectra. Aligned with the density functional theory calculations of the binding energies of peroxydisulfate on the slab models, built via Bernal stacking of graphitic carbon layers on the diamond plane, isothermal titration calorimetry measurements suggested that the binding affinity of peroxydisulfate decreased as the sp2/sp3 ratio increased. Therefore, the enhancing effect of graphitization arose from the electrical conductivity of nanodiamonds, which increased proportionally with graphitization extent.
Original language | English |
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Article number | 120205 |
Journal | Applied Catalysis B: Environmental |
Volume | 293 |
DOIs | |
Publication status | Published - 2021 Sept 15 |
Bibliographical note
Funding Information:This study was supported by a National Research Foundation of Korea grant funded by the Korean government (MSIP) [grant no. NRF-2018R1A4A1022194 ] and the National Research Foundation of Korea grant funded by the Ministry of Science, ICT, and Future Planning [grant No. 2016M3A7B4909318 ].
Publisher Copyright:
© 2021 Elsevier B.V.
Keywords
- Electron transfer-mediating capacity
- Graphitized nanodiamonds
- Non-radical mechanism
- Peroxydisulfate activation
- Surface affinity
ASJC Scopus subject areas
- Catalysis
- General Environmental Science
- Process Chemistry and Technology