Hydroxyl radicals dominate reoxidation of oxide-derived Cu in electrochemical CO2 reduction.
Nat Commun
; 13(1): 3694, 2022 Jun 27.
Article
em En
| MEDLINE
| ID: mdl-35760802
ABSTRACT
Cuδ+ sites on the surface of oxide-derived copper (OD-Cu) are of vital importance in electrochemical CO2 reduction reaction (CO2RR). However, the underlying reason for the dynamically existing Cuδ+ species, although thermodynamically unstable under reductive CO2RR conditions, remains uncovered. Here, by using electron paramagnetic resonance, we identify the highly oxidative hydroxyl radicals (OHâ¢) formed at room temperature in HCO3- solutions. In combination with in situ Raman spectroscopy, secondary ion mass spectrometry, and isotope-labelling, we demonstrate a dynamic reduction/reoxidation behavior at the surface of OD-Cu and reveal that the fast oxygen exchange between HCO3- and H2O provides oxygen sources for the formation of OH⢠radicals. In addition, their continuous generations can cause spontaneous oxidation of Cu electrodes and produce surface CuOx species. Significantly, this work suggests that there is a "seesaw-effect" between the cathodic reduction and the OHâ¢-induced reoxidation, determining the chemical state and content of Cuδ+ species in CO2RR. This insight is supposed to thrust an understanding of the crucial role of electrolytes in CO2RR.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Nat Commun
Ano de publicação:
2022
Tipo de documento:
Article