Electrochemical reduction of nitrate on boron-doped diamond electrodes: Effects of surface termination and boron-doping level

Peijing Kuang, Keisuke Natsui, Chuanping Feng, Yasuaki Einaga

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

This study is among the first to systematically study the electrochemical reduction of nitrate on boron-doped diamond (BDD) films with different surface terminations and boron-doping levels. The highest nitrate reduction efficiency was 48% and the highest selectivity in the production of nitrogen gas was 44.5%, which were achieved using a BDD electrode with a hydrogen-terminated surface and a B/C ratio of 1.0%. C–H bonds served as the anchor points for attracting NO3 anions close to the electrode surface, and thus accelerating the formation of NO3(ads). Compared to oxygen termination, hydrogen-terminated BDD exhibited higher electrochemical reactivity for reducing nitrate, resulting from the formation of shallow acceptor states and small interfacial band bending. The hydrophobicity of the hydrogen-terminated BDD inhibited water electrolysis and the subsequent adsorption of atomic hydrogen, leading to increased selectivity in the production of nitrogen gas. A BDD electrode with a boron-doping level of 1.0% increased the density of acceptor states, thereby enhancing the conductivity and promoting the formation of C–H bonds after the cathodic reduction pretreatment leading to the direct reduction of nitrate.

Original languageEnglish
Article number126364
JournalChemosphere
Volume251
DOIs
Publication statusPublished - 2020 Jul

Keywords

  • Boron-doping level
  • Investigation of mechanism
  • Nitrate reduction
  • Nitrogen gas selectivity
  • Surface termination

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Chemistry(all)
  • Pollution
  • Health, Toxicology and Mutagenesis

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