Cobalt Metallopeptide Electrocatalyst for the Selective Reduction of Nitrite to Ammonium
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, vol.140, no.49, pp.16888-16892, 2018 (SCI-Expanded, Scopus)
- 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.