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  • In Situ Scanning Tunneling ...
    Wang, Xiang; Cai, Zhen‐Feng; Wang, Yu‐Qi; Feng, Ya‐Chen; Yan, Hui‐Juan; Wang, Dong; Wan, Li‐Jun

    Angewandte Chemie International Edition, September 7, 2020, Letnik: 59, Številka: 37
    Journal Article

    We report a molecular investigation of a cobalt phthalocyanine (CoPc)‐catalyzed CO2 reduction reaction by electrochemical scanning tunneling microscopy (ECSTM). An ordered adlayer of CoPc was prepared on Au(111). Approximately 14 % of the adsorbed species appeared with high contrast in a CO2‐purged electrolyte environment. The ECSTM experiments indicate the proportion of high‐contrast species correlated with the reduction of CoIIPc (−0.2 V vs. saturated calomel electrode (SCE)). The high‐contrast species is ascribed to the CoPc‐CO2 complex, which is further confirmed by theoretical simulation. The sharp contrast change from CoPc‐CO2 to CoPc is revealed by in situ ECSTM characterization of the reaction. Potential step experiments provide dynamic information for the initial stage of the reaction, which include the reduction of CoPc and the binding of CO2, and the latter is the rate‐limiting step. The rate constant of the formation and dissociation of CoPc‐CO2 is estimated on the basis of the in situ ECSTM experiment. Imaging the electrocatalytic process: The cobalt‐phthalocyanine‐catalyzed CO2 reduction reaction is investigated by electrochemical scanning tunneling microscopy at the molecular scale. The molecular processes of the reaction, including the reduction of CoII, the binding of CO2, and the subsequent process, are revealed.