ClAg₁₄(C≡C^tBu)₁₂ Nanoclusters as Efficient and Selective Electrocatalysts Toward Industrially Relevant CO₂ Conversion

Atomically precise metal nanoclusters (NCs) have emerged as a promising frontier in the field of electrochemical CO₂ reduction reactions (CO₂RR) because of their distinctive catalytic properties. Although numerous metal NCs are developed for CO₂RR, 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 ClAg₁₄(C≡C^tBu)₁₂⁺ NCs, which exhibit remarkable efficiency in catalyzing CO₂-to-CO electroreduction with a CO selectivity of over 99% are reported. The underlying mechanisms behind this extraordinary CO₂RR activity of ClAg₁₄(C≡C^tBu)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 CO₂RR and suppressed hydrogen production. Furthermore, industrially relevant CO₂-to-CO electroreduction using ClAg₁₄(C≡C^tBu)₁₂⁺ NCs in a zero-gap CO₂ 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.