Ultrastable Copper Superatom

Atomically coinage metal nanoclusters are highly attractive for various applications including catalysis, photochemistry, and energy conversion. While Cu nanoclusters are low cost, their development has lagged behind that of Au and Ag counterparts due to their inherent instability primarily caused by the low Cu(I)/Cu(0) reduction potential. Therefore, the synthesis of stable Cu(0)-containing nanoclusters remains a formidable challenge. Herein, we report the first 6-electron superatomic copper nanocluster, [Cu 45 H 6 (C≡CR) 18 (OAc) 15 ] ( Cu 45 ). This cluster has remarkable stability, being resistant to thermal, oxidative, reductive, acidic, and basic treatments. Single-crystal X-ray diffraction analysis and time-dependent DFT calculations reveal that the outstanding stability of Cu 45 is attributed to its superatomic electronic configuration (1S 2 1P 4 ) and strong copper–ligand interactions. Furthermore, Cu 45 is the first well-defined Cu superatom electrocatalyst used for CO 2 -to-C 2 H 4 electrocatalysis, which exhibits outstanding performance with a maximum Faradaic efficiency for C 2+ products of 81.8% (58% for ethene), surpassing all known copper cluster catalysts. In situ ATR-SEIRAS and theoretical calculations reveal that Cu 45 effectively activates CO 2 and promotes C–C coupling, thereby facilitating the formation of C 2+ products. This work provides new insights into the design of robust Cu nanoclusters for electrocatalytic applications, enabling their broader application in future research and technology development.