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Optimizing boron doping in diamond electrodes for PFOA mineralization : 14C labeling and DFT studies.

Szopińska, Małgorzata ; Olejnik, Adrian ; Kaczmarzyk-Knitter, Iwona ; Jakóbczyk, Paweł ; Falås, Per LU ; Davidsson, Åsa LU orcid ; Cimbritz, Michael LU orcid ; Ficek, Mateusz ; Skiba, Franciszek and Walczak, Natalia , et al. (2025) In Journal of Hazardous Materials 501.
Abstract

Boron-doped diamond (BDD) films were synthesized via microwave plasma-enhanced chemical vapor deposition at five boron-to-carbon ratios to investigate dopant effects on perfluorooctanoic acid (PFOA) electrooxidation and electrode stability. Raman spectroscopy revealed that excessive boron (≥10k ppm) produced sp²-rich regions indicative of structural degradation. Electrodes optimized at ∼10k ppm boron exhibited carrier mobility of ∼98 cm/V -1s -1 and achieved threefold higher oxidation rate constants compared to low-doped analogs. PFOA electrooxidation followed first-order kinetics, yielding up to 60 % removal and 50 % mineralization to CO₂, confirmed via ¹⁴C-labeled tracing. Lower-doped electrodes generated more C₄-C₇... (More)

Boron-doped diamond (BDD) films were synthesized via microwave plasma-enhanced chemical vapor deposition at five boron-to-carbon ratios to investigate dopant effects on perfluorooctanoic acid (PFOA) electrooxidation and electrode stability. Raman spectroscopy revealed that excessive boron (≥10k ppm) produced sp²-rich regions indicative of structural degradation. Electrodes optimized at ∼10k ppm boron exhibited carrier mobility of ∼98 cm/V -1s -1 and achieved threefold higher oxidation rate constants compared to low-doped analogs. PFOA electrooxidation followed first-order kinetics, yielding up to 60 % removal and 50 % mineralization to CO₂, confirmed via ¹⁴C-labeled tracing. Lower-doped electrodes generated more C₄-C₇ perfluorocarboxylic acid intermediates, indicating slower kinetics. Mechanistic studies using methanol as a hydroxyl radical scavenger demonstrated that •OH plays a secondary role, with direct electron transfer (DET) dominating PFOA oxidation. A modified validated method for quantifying 11 PFCAs, including those regulated under EU Directive 2020/2184, is reported. Density functional theory simulations supported the hypothesis that boron doping strengthens PFOA-surface covalent-like bonding and facilitates electron transfer. This work establishes optimal boron doping for balancing conductivity, stability, and oxidation performance, and provides design principles for BDD electrodes in advanced electrochemical PFAS treatment systems.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Hazardous Materials
volume
501
article number
140752
pages
9 pages
publisher
Elsevier
external identifiers
  • pmid:41406533
  • scopus:105024753951
ISSN
1873-3336
DOI
10.1016/j.jhazmat.2025.140752
language
English
LU publication?
yes
additional info
Copyright © 2025 The Authors. Published by Elsevier B.V. All rights reserved.
id
fe9a282b-baaf-49c1-ad6d-80eb68139bcf
date added to LUP
2026-01-05 09:08:41
date last changed
2026-01-09 02:54:15
@article{fe9a282b-baaf-49c1-ad6d-80eb68139bcf,
  abstract     = {{<p>Boron-doped diamond (BDD) films were synthesized via microwave plasma-enhanced chemical vapor deposition at five boron-to-carbon ratios to investigate dopant effects on perfluorooctanoic acid (PFOA) electrooxidation and electrode stability. Raman spectroscopy revealed that excessive boron (≥10k ppm) produced sp²-rich regions indicative of structural degradation. Electrodes optimized at ∼10k ppm boron exhibited carrier mobility of ∼98 cm/V -1s -1 and achieved threefold higher oxidation rate constants compared to low-doped analogs. PFOA electrooxidation followed first-order kinetics, yielding up to 60 % removal and 50 % mineralization to CO₂, confirmed via ¹⁴C-labeled tracing. Lower-doped electrodes generated more C₄-C₇ perfluorocarboxylic acid intermediates, indicating slower kinetics. Mechanistic studies using methanol as a hydroxyl radical scavenger demonstrated that •OH plays a secondary role, with direct electron transfer (DET) dominating PFOA oxidation. A modified validated method for quantifying 11 PFCAs, including those regulated under EU Directive 2020/2184, is reported. Density functional theory simulations supported the hypothesis that boron doping strengthens PFOA-surface covalent-like bonding and facilitates electron transfer. This work establishes optimal boron doping for balancing conductivity, stability, and oxidation performance, and provides design principles for BDD electrodes in advanced electrochemical PFAS treatment systems. </p>}},
  author       = {{Szopińska, Małgorzata and Olejnik, Adrian and Kaczmarzyk-Knitter, Iwona and Jakóbczyk, Paweł and Falås, Per and Davidsson, Åsa and Cimbritz, Michael and Ficek, Mateusz and Skiba, Franciszek and Walczak, Natalia and Kozłowska-Tylingo, Katarzyna and Bogdanowicz, Robert and Pierpaoli, Mattia}},
  issn         = {{1873-3336}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Journal of Hazardous Materials}},
  title        = {{Optimizing boron doping in diamond electrodes for PFOA mineralization : <sup>14</sup>C labeling and DFT studies.}},
  url          = {{http://dx.doi.org/10.1016/j.jhazmat.2025.140752}},
  doi          = {{10.1016/j.jhazmat.2025.140752}},
  volume       = {{501}},
  year         = {{2025}},
}