Probing Cluster−π Interactions between Cu_n^– and C₂H₂/C₂H₄ for Gas Separation

Abstract

Copper-related materials are used for separation of ethylene and acetylene gases in chemistry; however, the precise mechanism regarding selectivity is elusive to be fully understood. Here, we have conducted a joint experimental and theoretical study of the Cu n – (n = 7–30) clusters in reacting with C2H4 and C2H2. It is found that all of the Cu n – clusters readily react with C2H2, giving rise to C2H2-addition products; however, Cu18 – and Cu19 – do not react with C2H4. We illustrate the superatomic stability of Cu18 – and advocate its availability to separate C2H4 from C2H2. Further, we demonstrate the atomically precise mechanism regarding selectivity by fully unveiling the size-dependent cluster−π interactions.