Performance of Magnéli phase Ti4O7 and Ti3+ self-doped TiO2 as oxygen vacancy-rich titanium oxide anodes: Comparison in terms of treatment efficiency, anodic degradative pathways, and long-term stability

Minjeong Kim, Jaemin Choi, Woonghee Lee, Yong Yoon Ahn, Hangil Lee, Kangwoo Cho, Jaesang Lee

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

This study compared hydrogen annealing and cathodic polarization (producing Magnéli phases and Ti3+ self-doped TiO2, respectively) as strategies to fabricate electrically conducting titanium oxides through oxygen non-stoichiometry creation for anodic water treatment. Electrochemical characterization techniques suggested that Ti4O7 best-suited for redox electrocatalysis among the Magnéli phases exhibited higher electrical conductivity than the self-doped TiO2. This aligned with the superiority of Ti4O7 over the self-doped TiO2 in chlorine evolution and anodic organic oxidation. Hydroxyl radical primarily contributed to anodic oxidation by two conductive titanium oxides at sulfate-based electrolyte, based on the retarding effects of radical scavengers, multi-activity assessment, electron paramagnetic resonance spectral features, and product distribution. Repetitive batch experiments and long-term tests in continuous operation mode demonstrated that self-doped TiO2 underwent more drastic performance reduction than Ti4O7. This accorded with the self-doped TiO2 being more vulnerable to activity loss, chemical alteration, and structural damage during prolonged application.

Original languageEnglish
Article number122993
JournalApplied Catalysis B: Environmental
Volume337
DOIs
Publication statusPublished - 2023 Nov 15

Bibliographical note

Funding Information:
This work was supported by the National Research Foundation of Korea (NRF) Grant funded by the Korean Government (MSTI) ( NRF-2022M3H4A4097524 ).

Publisher Copyright:
© 2023 Elsevier B.V.

Keywords

  • Anodic oxidation
  • Hydroxyl radical
  • Long-term stability
  • Magnéli phases
  • Ti self-doped TiO

ASJC Scopus subject areas

  • Catalysis
  • General Environmental Science
  • Process Chemistry and Technology

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