Linker Driven Site-specific Catalysis in Atomically Precise Silver Cluster-Assemblies

Abstract

Metal nanoclusters (NCs) exhibit potential as catalysts for electrochemical studies, providing atomic-level insights into mechanisms. However, it remains elusive to construct an integrated catalyst with a molecular-level understanding of its mechanism, especially in silver cluster assemblies. In this study, we have shown that atomically precise Ag12 cluster assemblies Ag12-py, Ag12-pyz, Ag12-bpy, Ag12-bpa, Ag12-azopy, (where Ag12 = secondary building unit, Py = pyridine, pyz = pyrazine, bpy = 4,4′-Bipyridine, bpa = 1,2-Bis(4-pyridyl)ethane, azopy = 4,4′-Azopyridine), serve as paradigms for demonstrating the hydrogen evolution reaction (HER), where the catalytic activity is fine-tuned by two functional units: the cluster core and the linkers. Atomic resolution of such catalysts permits tracing the reaction process via experiments coupled with theory and structural analysis. Site-specific catalysis for Ag12pyz induced by metal cluster assembly & linker synergy can be accurately elucidated to dominate in the series. Taking advantage of pyrazine linker for its less basicity and isotropic nature of inter-cluster interactions in Ag12-pyz, it shows enhanced catalytic activity and selective hydrogen adsorption at the sulfur site, different from others in the series with nearly five times higher efficiency. This work on a series of silver cluster assemblies provides a substantial structural model to understand the catalyst’s active site and activity, further driving advancements in functional cluster-based assemblies.