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Abstract Sn‐based materials are identified as promising catalysts for the CO2electroreduction (CO2RR) to formate (HCOO−). However, their insufficient selectivity and activity remain grand challenges. A new type of SnO2nanosheet with simultaneous N dopants and oxygen vacancies (VO‐rich N‐SnO2NS) for promoting CO2conversion to HCOO−is reported. Due to the likely synergistic effect of N dopant andVO, theVO‐rich N‐SnO2NS exhibits high catalytic selectivity featured by an HCOO−Faradaic efficiency (FE) of 83% at−0.9 V and an FE of>90% for all C1 products (HCOO−and CO) at a wide potential range from −0.9 to−1.2 V. Low coordination Sn–N moieties are the active sites with optimal electronic and geometric structures regulated byVOand N dopants. Theoretical calculations elucidate that the reaction free energy of HCOO* protonation is decreased on theVO‐rich N‐SnO2NS, thus enhancing HCOO−selectivity. The weakened H* adsorption energy also inhibits the hydrogen evolution reaction, a dominant side reaction during the CO2RR. Furthermore, using the catalyst as the cathode, a spontaneous Galvanic Zn‐CO2cell and a solar‐powered electrolysis process successfully demonstrated the efficient HCOO−generation through CO2conversion and storage.
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Cylindrical C 96 Fullertubes: A Highly Active Metal‐Free O 2 ‐Reduction Electrocatalyst
Abstract A new isolation protocol was recently reported for highly purified metallic FullertubesD5h‐C90,D3d‐C96, andD5d‐C100,which exhibit unique electronic features. Here, we report the oxygen reduction electrocatalytic behavior of C60, C70(spheroidal fullerenes), and C90, C96, and C100(tubular fullerenes) using a combination of experimental and theoretical approaches. C96(a metal‐free catalyst) displayed remarkable oxygen reduction reaction (ORR) activity, with an onset potential of 0.85 V and a halfway potential of 0.75 V, which are close to the state‐of‐the‐art Pt/C benchmark catalyst values. We achieved an excellent power density of 0.75 W cm−2using C96as a modified cathode in a proton‐exchange membrane fuel cell, comparable to other recently reported efficient metal‐free catalysts. Combined band structure (experimentally calculated) and free‐energy (DFT) investigations show that both favorable energy‐level alignment active catalytic sites on the carbon cage are responsible for the superior activity of C96.
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- Award ID(s):
- 1856461
- PAR ID:
- 10369513
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 61
- Issue:
- 21
- ISSN:
- 1433-7851
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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