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.
Highly selective production of valuable ethylene from electrocatalytic CO 2 reduction reaction (ECO 2 RR) is particularly desirable yet challenging. Morphology engineering is an effective strategy for catalyst design, which can adjust the electronic structure of catalyst surface, change the adsorption behavior of critical reaction intermediates over catalyst surface, and thus regulate the activity of electrocatalytic CO 2 reduction reaction. In this work, we prepared copper phosphate catalysts with different morphologies and tested their catalytic activity for the ECO 2 RR in the flow cell. Compared with irregular flocculent aggregates, copper phosphate nanospheres exhibit a high and stable ethylene Faradaic efficiency of 47% with high current density of 350 mA·cm − 2 , which is higher than the 200 mA·cm − 2 required for industrial applications. The catalysts were extensively characterized by SEM, EDS, XRD, ICP-OES, XPS, BET and CO-TPD. Combining the characterization results and activity data, we found that the superior spherical morphology of copper phosphate can increase the electron density around Cu, stabilize the Cu + species on the surface through the electron transfer between P and Cu, and adjust the adsorption strength of CO intermediates (*CO) to enhance the productivity of C 2+ products. This work provides new insights into catalyst design for highly efficient C 2 H 4 production from the electrocatalytic CO 2 reduction reaction by tuning morphologies of Cu-based catalysts.
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