Exploration of Gas-Dependent Self-Adaptive Reconstruction Behavior of Cu2O for Electrochemical CO2 Conversion to Multi-Carbon Products

Structural reconstruction of electrocatalysts plays a pivotal role in catalytic performances for CO 2 reduction reaction (CO 2 RR), whereas the behavior is by far superficially understood. Here, we report that CO 2 accessibility results in a universal self-adaptive structural reconstruction from Cu 2 O to Cu@Cu x O composites, ending with feeding gas-dependent microstructures and catalytic performances. The CO 2 -rich atmosphere favors reconstruction for CO 2 RR, whereas the CO 2 -deficient one prefers that for hydrogen evolution reaction. With the assistance of spectroscopic analysis and theoretical calculations, we uncover a CO 2 -induced passivation behavior by identifying a reduction-resistant but catalytic active Cu(I)-rich amorphous layer stabilized by *CO intermediates. Additionally, we find extra CO production is indispensable for the robust production of C 2 H 4 . An inverse correlation between durability and FE CO /FE C2H4 is disclosed, suggesting that the self-stabilization process involving the absorption of *CO intermediates on Cu(I) sites is essential for durable electrolysis. Guided by this insight, we design hollow Cu 2 O nanospheres for durable and selective CO 2 RR electrolysis in producing C 2 H 4 . Our work recognizes the previously overlooked passivation reconstruction and self-stabilizing behavior and highlights the critical role of the local atmosphere in modulating reconstruction and catalytic processes.