Regulating electron transfer over asymmetric low-spin Co(II) for highly selective electrocatalysis

Kuang Hsu Wu*, Yuefeng Liu, Xin Tan, Yangyang Liu, Yangming Lin, Xing Huang, Yuxiao Ding, Bing Jian Su, Bingsen Zhang, Jin Ming Chen, Wensheng Yan, Sean C. Smith, Ian R. Gentle*, Shenlong Zhao*

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    63 Citations (Scopus)

    Abstract

    Modulating the steric-electronic configuration of metal-organic centers is key for tuning the activity and selectivity of heterogeneous reactions, especially multi-electron transfer reactions. Here, three different asymmetric metal-organic complexes with unique steric-electronic structures are immobilized on nanocarbon for an electron-transfer-controlled oxygen reduction reaction. The strong-field ligand-induced low-spin (LS) CoII creates a necessary steric configuration for regulating reaction selectivity through ligand's proton transfer ability, for which acidic diamine ligands facilitate a four-electron transfer (94%), whereas basic ligands drive a highly selective two-electron route (97%). The steric-electronic regulation of the reaction selectivity at catalytic sites is characterized using X-ray absorption spectroscopy, reaction kinetic path analysis, and density functional theory calculation. Our results indicate that an LS state of CoII with asymmetric coordination is necessary to form a unique “flytrap” structure to promote O2 capture for the subsequent proton-coupled electron transfer, which is regulated by the Brønsted acidity of coordinating ligands.

    Original languageEnglish
    Pages (from-to)372-385
    Number of pages14
    JournalChem Catalysis
    Volume2
    Issue number2
    DOIs
    Publication statusPublished - 17 Feb 2022

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