Understanding the effect of host structure of nitrogen doped ultrananocrystalline diamond electrode on electrochemical carbon dioxide reduction

Namal Wanninayake, Qianxiang Ai, Ruixin Zhou, Md Ariful Hoque, Sidney Herrell, Marcelo I. Guzman, Chad Risko, Doo Young Kim

Research output: Contribution to journalArticlepeer-review

48 Scopus citations

Abstract

Despite recent literature reporting the remarkable electrochemical CO2 reduction reaction (CO2RR) performance of nitrogen-doped graphitic carbon materials (sp2-carbon) and nitrogen-doped diamond materials (sp3-carbon), no systematic studies have been conducted on the catalytic activities of hybrid carbon nanomaterials between diamond and graphitic extremes. In this study, nitrogen-doped ultra-nanocrystalline diamond thin films were prepared by a microwave-assisted chemical vapor deposition technique. The ratio of sp2-carbon phase to sp3-carbon phase was controlled by varying growth conditions. Our results confirm that nitrogen-doped sp2-carbon (graphitic) rich electrodes have better selectivity for the CO2RR products over the nitrogen-doped sp3-carbon rich electrodes, indicating that the host structure of nitrogen dopants is crucial for the catalytic activity. Nitrogen-doped sp2-carbon electrodes present Faradaic efficiency for CO production up to 82% with excellent activity and selectivity. The vital role of the host structure and the potential catalytic sites were detailed by density functional theory (DFT) calculations.

Original languageEnglish
Pages (from-to)408-419
Number of pages12
JournalCarbon
Volume157
DOIs
StatePublished - Feb 2020

Bibliographical note

Publisher Copyright:
© 2019 Elsevier Ltd

ASJC Scopus subject areas

  • General Chemistry
  • General Materials Science

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