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Title: Buffer Assists Electrocatalytic Nitrite Reduction by a Cobalt Macrocycle Complex
This work reports a combined experimental and computational study of the activation of an otherwise catalytically inactive cobalt complex, [Co(TIM)Br2]+, for aqueous nitrite reduction. The presence of phosphate buffer leads to efficient electrocatalysis, with rapid reduction to ammonium occurring close to the thermodynamic potential and with high Faradaic efficiency. At neutral pH, increasing buffer concentrations increase catalytic current while simultaneously decreasing overpotential, although high concentrations have an inhibitory effect. Controlled potential electrolysis and rotating ring-disk electrode experiments indicate that ammonium is directly produced from nitrite by [Co(TIM)Br2]+, along with hydroxylamine. Mechanistic investigations implicate a vital role for the phosphate buffer, specifically as a proton shuttle, although high buffer concentrations inhibit catalysis. These results indicate a role for buffer in the design of electrocatalysts for nitrogen oxide conversion.  more » « less
Award ID(s):
2102442 1566258
NSF-PAR ID:
10349504
Author(s) / Creator(s):
; ; ; ; ;
Date Published:
Journal Name:
Inorganic Chemistry
ISSN:
0020-1669
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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