Wang JW, Luo ZM, Yang G, Gil-Sepulcre M, Kupfer S, Rüdiger O, Ouyang G. Highly efficient electrocatalytic CO
2 reduction by a Cr
III quaterpyridine complex.
Proc Natl Acad Sci U S A 2024;
121:e2319288121. [PMID:
38527206 PMCID:
PMC10998623 DOI:
10.1073/pnas.2319288121]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Accepted: 02/07/2024] [Indexed: 03/27/2024] Open
Abstract
Design tactics and mechanistic studies both remain as fundamental challenges during the exploitations of earth-abundant molecular electrocatalysts for CO2 reduction, especially for the rarely studied Cr-based ones. Herein, a quaterpyridyl CrIII catalyst is found to be highly active for CO2 electroreduction to CO with 99.8% Faradaic efficiency in DMF/phenol medium. A nearly one order of magnitude higher turnover frequency (86.6 s-1) over the documented Cr-based catalysts (<10 s-1) can be achieved at an applied overpotential of only 190 mV which is generally 300 mV lower than these precedents. Such a high performance at this low driving force originates from the metal-ligand cooperativity that stabilizes the low-valent intermediates and serves as an efficient electron reservoir. Moreover, a synergy of electrochemistry, spectroelectrochemistry, electron paramagnetic resonance, and quantum chemical calculations allows to characterize the key CrII, CrI, Cr0, and CO-bound Cr0 intermediates as well as to verify the catalytic mechanism.
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