期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2020
卷号：117
期号：17
页码：9194-9201
DOI：10.1073/pnas.1918602117
出版社：The National Academy of Sciences of the United States of America
摘要：Promotion of C–C bonds is one of the key fundamental questions in the field of CO 2 electroreduction. Much progress has occurred in developing bulk-derived Cu-based electrodes for CO 2 -to-multicarbons (CO 2 -to-C 2 ), especially in the widely studied class of high-surface-area “oxide-derived” copper. However, fundamental understanding into the structural characteristics responsible for efficient C–C formation is restricted by the intrinsic activity of these catalysts often being comparable to polycrystalline copper foil. By closely probing a Cu nanoparticle (NP) ensemble catalyst active for CO 2 -to-C 2 , we show that bias-induced rapid fusion or “electrochemical scrambling” of Cu NPs creates disordered structures intrinsically active for low overpotential C 2 formation, exhibiting around sevenfold enhancement in C 2 turnover over crystalline Cu. Integrating ex situ, passivated ex situ, and in situ analyses reveals that the scrambled state exhibits several structural signatures: a distinct transition to single-crystal Cu 2 O cubes upon air exposure, low crystallinity upon passivation, and high mobility under bias. These findings suggest that disordered copper structures facilitate C–C bond formation from CO 2 and that electrochemical nanocrystal scrambling is an avenue toward creating such catalysts.
关键词：electrocatalysis ; nanomaterials ; CO 2 reduction ; structure dynamics
