Real‐time Monitoring Reveals Dissolution/Redeposition Mechanism in Copper Nanocatalysts during the Initial Stages of the CO2 Reduction Reaction

다국어 초록 (Multilingual Abstract)

Size, morphology, and surface sites of electrocatalysts have a major impact on their performance. Understanding how, when, and why these parameters change under operating conditions is of importance for designing stable, active, and selective catalysts. Herein, we study the reconstruction of a Cu‐based nanocatalysts during the startup phase of the electrochemical CO2 reduction reaction by combining results from electrochemical in situ transmission electron microscopy with operando X‐ray absorption spectroscopy. We reveal that dissolution followed by redeposition, rather than coalescence, is the mechanism responsible for the size increase and morphology change of the electrocatalyst. Furthermore, we point out the key role played by the formation of copper oxides in the process. Understanding of the underlying processes opens a pathway to rational design of Cu electro (re)deposited catalysts and to stability improvement for catalysts fabricated by other methods.
The reconstruction of a Cu‐based nanocatalyst during the startup phase of electrochemical CO2 reduction is studied by combining results from electrochemical in situ transmission electron microscopy with operando X‐ray absorption spectroscopy. The mechanism responsible for the size increase and morphology change of the electrocatalyst is revealed, as is the key role played by the formation of copper oxides in the process.