Persulfate activation by nanodiamond-derived carbon onions: Effect of phase transformation of the inner diamond core on reaction kinetics and mechanisms

Bowen Yang, Haisu Kang, Young Jin Ko, Heesoo Woo, Geondu Gim, Jaemin Choi, Jaesung Kim, Kangwoo Cho, Eun Ju Kim, Seung Geol Lee, Hongshin Lee, Jaesang Lee

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

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 languageEnglish
Article number120205
JournalApplied Catalysis B: Environmental
Volume293
DOIs
Publication statusPublished - 2021 Sep 15

Keywords

  • Electron transfer-mediating capacity
  • Graphitized nanodiamonds
  • Non-radical mechanism
  • Peroxydisulfate activation
  • Surface affinity

ASJC Scopus subject areas

  • Catalysis
  • Environmental Science(all)
  • Process Chemistry and Technology

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