Vacancy-Induced Modulation on the Interface Properties of Au25(SCH3)18 Nanoclusters Supported on Defective Graphene

Abstract

Atomically precise metal nanoclusters (NCs) are frequently loaded onto various substrates for numerous catalytic applications, yet the interfacial interaction remains poorly understood. In this study, we performed ab initio molecular dynamics (AIMD) simulations to systematically investigate the interfacial dynamics of thiolated-protected Au25(SR)18 NC on graphene substrate with varying vacancy defect sizes. The results revealed that when the vacancy defect features a convex-shaped armchair edge, the vacancy edges would undergo severe reconstruction and reduce the substrate reactivity, which cannot effectively anchor the Au25 NC and induce high mobility on graphene. By contrast, when the vacancy defect features a concave-shaped armchair edge, the present unsaturated sp2 dangling bond imparts high reactivity to the vacancy edge, which form strong chemical interaction with Au25 and lead to facile and spontaneous removal of staple Au-SCH3 moiety from the protecting -S-Au-S-Au-S- motif. The etched Au25 NC with exposed active Au site can efficiently facilitate the electrocatalytic CO2 reduction to CO with moderate energy barriers. This work reveals the significant role of defect edge of graphene in modulating the interfacial behavior of metal NCs, providing a promising strategy to regulate the interface and catalytic properties of atomically precise metal NCs.