ClAg 14 (C≡C t Bu) 12 Nanoclusters as Efficient and Selective Electrocatalysts Toward Industrially Relevant CO 2 Conversion.

Atomically precise metal nanoclusters (NCs) have emerged as a promising frontier in the field of electrochemical CO 2 reduction reactions (CO 2 RR) because of their distinctive catalytic properties. Although numerous metal NCs are developed for CO 2 RR, their use in practical applications has suffered from their low-yield synthesis and insufficient catalytic activity. In this study, the large-scale synthesis and electrocatalytic performance of ClAg 14 (C≡C t Bu) 12 + NCs, which exhibit remarkable efficiency in catalyzing CO 2 -to-CO electroreduction with a CO selectivity of over 99% are reported. The underlying mechanisms behind this extraordinary CO 2 RR activity of ClAg 14 (C≡C t Bu) 12 + NCs are investigated by a combination of electrokinetic and theoretical studies. These analyses reveal that different active sites, generated through electrochemical activation, have unique adsorption properties for the reaction intermediates, leading to enhanced CO 2 RR and suppressed hydrogen production. Furthermore, industrially relevant CO 2 -to-CO electroreduction using ClAg 14 (C≡C t Bu) 12 + NCs in a zero-gap CO 2 electrolyzer, achieving high energy efficiency of 51% and catalyst activity of over 1400 A g -1 at a current density of 400 mA cm -2 is demonstrated.