Boosting CO2 Electroreduction over a Covalent Organic Framework in the Presence of Oxygen.
Angew Chem Int Ed Engl
; 63(14): e202319472, 2024 Apr 02.
Article
en En
| MEDLINE
| ID: mdl-38320964
ABSTRACT
Herein, we propose an oxygen-containing species coordination strategy to boost CO2 electroreduction in the presence of O2. A two-dimensional (2D) conjugated metal-covalent organic framework (MCOF), denoted as NiPc-Salen(Co)2-COF that is composed of the Ni-phthalocyanine (NiPc) unit with well-defined Ni-N4-O sites and the salen(Co)2 moiety with binuclear Co-N2O2 sites, is developed and synthesized for enhancing the CO2RR under aerobic condition. In the presence of O2, one of the Co sites in the NiPc-Salen(Co)2-COF that coordinated with the intermediate of *OOH from ORR could decrease the energy barrier of the activation of CO2 molecules and stabilize the key intermediate *COOH of the CO2RR over the adjacent Co center. Besides, the oxygen species axially coordinated Ni-N4-O sites can favor in reducing the energy barrier of the intermediate *COOH formation for the CO2RR. Thus, NiPc-Salen(Co)2-COF exhibits high oxygen-tolerant CO2RR performance and achieves outstanding CO Faradaic efficiency (FECO) of 97.2 % at -1.0â
V vs. the reversible hydrogen electrode (RHE) and a high CO partial current density of 40.3â
mA cm-2 at -1.1â
V in the presence of 0.5 % O2, which is superior to that in pure CO2 feed gas (FECO=94.8 %, jCO=19.9â
mA cm-2). Notably, the NiPc-Salen(Co)2-COF achieves an industrial-level current density of 128.3â
mA cm-2 in the flow-cell reactor with 0.5 % O2 at -0.8â
V, which is higher than that in pure CO2 atmosphere (jCO=104.8â
mA cm-2). It is worth noting that an excellent FECO of 86.8 % is still achieved in the presence of 5 % O2 at -1.0â
V. This work provides an effective strategy to enable the CO2RR under O2 atmosphere by utilizing the *OOH intermediates of ORR to boost CO2 electroreduction.
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MEDLINE
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En
Revista:
Angew Chem Int Ed Engl
Año:
2024
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Article