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Abstract Organofunctionalized tetranuclear clusters [(MIICl)2(VIVO)2{((HOCH2CH2)(H)N(CH2CH2O))(HN(CH2CH2O)2)}2] (1, M=Co,2: M=Zn) containing an unprecedented oxometallacyclic {M2V2Cl2N4O8} (M=Co, Zn) framework have been prepared by solvothermal reactions. The new oxo‐alkoxide compounds were fully characterized by spectroscopic methods, magnetic susceptibility measurement, DFT and ab initio computational methods, and complete single‐crystal X‐ray diffraction structure analysis. The isostructural clusters are formed of edge‐sharing octahedral {VO5N} and trigonal bipyramidal {MO3NCl} units. Diethanolamine ligates the bimetallic lacunary double cubane core of1and2in an unusual two‐mode fashion, unobserved previously. In the crystalline state, the clusters of1and2are joined by hydrogen bonds to form a three‐dimensional network structure. Magnetic susceptibility data indicate weakly antiferromagnetic interactions between the vanadium centers [Jiso(VIV−VIV)=−5.4(1); −3.9(2) cm−1], and inequivalent antiferromagnetic interactions between the cobalt and vanadium centers [Jiso(VIV−CoII)=−12.6 and −7.5 cm−1] contained in1.
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Elucidation of the Synergistic Effect of Dopants and Vacancies on Promoted Selectivity for CO 2 Electroreduction to Formate
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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- Award ID(s):
- 1804326
- PAR ID:
- 10454547
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials
- Volume:
- 33
- Issue:
- 2
- ISSN:
- 0935-9648
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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