The development of CO2 electroreduction (CO2RR) catalysts based on covalent organic frameworks (COFs) is an emerging strategy to produce synthetic fuels. However, our understanding on catalytic mechanisms and structure-activity relationships for COFs is still limited but essential to the rational design of these catalysts. Herein, we report a newly devised CO2 reduction catalyst by loading single-atom centers, {fac-Mn(CO)(3)S}, (S = Br, CH3CN, H2O), within a bipyridylbased COF (COFbpyMn). COFbpyMn shows a low CO2RR onset potential (eta = 190 mV) and high current densities (>12 mA.cm(-2), at 550 mV overpotential) in water. TOFCO and TONCO values are as high as 1100 h-1 and 5800 (after 16 h), respectively, which are more than 10-fold higher than those obtained for the equivalent manganese-based molecular catalyst. Furthermore, we accessed key catalytic intermediates within a COF matrix by combining experimental and computational (DFT) techniques. The COF imposes mechanical constraints on the {fac-Mn(CO)(3)S} centers, offering a strategy to avoid forming the detrimental dimeric Mn-0-Mn-0, which is a resting state typically observed for the homologous molecular complex. The absence of dimeric species correlates to the catalytic enhancement. These findings can guide the rational development of isolated single-atom sites and the improvement of the catalytic performance of reticular materials.

Mechanically Constrained Catalytic Mn(CO)(3)Br Single Sites in a Two-Dimensional Covalent Organic Framework for CO2 Electroreduction in H2O

Federico Franco;
2021-01-01

Abstract

The development of CO2 electroreduction (CO2RR) catalysts based on covalent organic frameworks (COFs) is an emerging strategy to produce synthetic fuels. However, our understanding on catalytic mechanisms and structure-activity relationships for COFs is still limited but essential to the rational design of these catalysts. Herein, we report a newly devised CO2 reduction catalyst by loading single-atom centers, {fac-Mn(CO)(3)S}, (S = Br, CH3CN, H2O), within a bipyridylbased COF (COFbpyMn). COFbpyMn shows a low CO2RR onset potential (eta = 190 mV) and high current densities (>12 mA.cm(-2), at 550 mV overpotential) in water. TOFCO and TONCO values are as high as 1100 h-1 and 5800 (after 16 h), respectively, which are more than 10-fold higher than those obtained for the equivalent manganese-based molecular catalyst. Furthermore, we accessed key catalytic intermediates within a COF matrix by combining experimental and computational (DFT) techniques. The COF imposes mechanical constraints on the {fac-Mn(CO)(3)S} centers, offering a strategy to avoid forming the detrimental dimeric Mn-0-Mn-0, which is a resting state typically observed for the homologous molecular complex. The absence of dimeric species correlates to the catalytic enhancement. These findings can guide the rational development of isolated single-atom sites and the improvement of the catalytic performance of reticular materials.
2021
18-giu-2021
Pubblicato
https://pubs.acs.org/doi/10.1021/acscatal.1c00314
File in questo prodotto:
File Dimensione Formato  
acscatal.1c00314.pdf

Accesso chiuso

Tipologia: Documento in Versione Editoriale
Licenza: Copyright Editore
Dimensione 12.12 MB
Formato Adobe PDF
12.12 MB Adobe PDF   Visualizza/Apri   Richiedi una copia
cs1c00314_si_001.pdf

Accesso chiuso

Descrizione: supplementary file
Tipologia: Altro materiale allegato
Licenza: Copyright Editore
Dimensione 6.9 MB
Formato Adobe PDF
6.9 MB Adobe PDF   Visualizza/Apri   Richiedi una copia
acscatal.1c00314-Post_print.pdf

embargo fino al {0}

Tipologia: Bozza finale post-referaggio (post-print)
Licenza: Digital Rights Management non definito
Dimensione 12.63 MB
Formato Adobe PDF
12.63 MB Adobe PDF   Visualizza/Apri   Richiedi una copia
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11368/3044364
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 42
  • ???jsp.display-item.citation.isi??? 35
social impact