Cobalt Metallopeptide Electrocatalyst for the Selective Reduction of Nitrite to Ammonium

Guo Y., Stroka J. R., Kandemir B., Dickerson C. E., Bren K. L.

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, vol.140, no.49, pp.16888-16892, 2018 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 140 Issue: 49
  • Publication Date: 2018
  • Doi Number: 10.1021/jacs.8b09612
  • Journal Name: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.16888-16892
  • Middle East Technical University Affiliated: No

Abstract

A cobalt-tripeptide complex (CoGGH) is developed as an electrocatalyst for the selective six-electron, eight-proton reduction of nitrite to ammonium in aqueous buffer near neutral pH. The onset potential for nitrite reduction occurs at -0.65 V vs Ag/AgCl (1 M KCl). Controlled potential electrolysis at -0.90 V generates ammonium with a faradaic efficiency of 90 +/- 3% and a turnover number of 3550 +/- 420 over 5.5 h. CoGGH also catalyzes the reduction of the proposed intermediates nitric oxide and hydroxylamine to ammonium. These results reveal that a simple metallopeptide is an active functional mimic of the complex enzymes cytochrome c nitrite reductase and siroheme-containing nitrite reductase.