Chandrashekar Priyanka, Karmakar Arun, Aparna Ravari Kandy, Singh Laddi, Mondal Pradip Kumar, Kundu Subrata, Bhattacharyya Kalishankar, Mandal Sukhendu
School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram Kerala 69551 India
Electrochemical Process Engineering (EPE) Division, CSIR-Central Electrochemical Research Institute (CECRI) Karaikudi Tamil Nadu 630006 India
Chem Sci. 2025 Feb 26;16(13):5726-5734. doi: 10.1039/d4sc08408j. eCollection 2025 Mar 26.
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 Ag cluster assemblies Ag-py, Ag-pyz, Ag-bpy, Ag-bpa, Ag-azopy, (where Ag = secondary building unit, Py = pyridine, pyz = pyrazine, bpy = 4,4'-bipyridine, bpa = 1,2-bis(4-pyridyl)ethane, and azopy = 4,4'-azopyridine) serve as paradigms for demonstrating the hydrogen evolution reaction (HER), where the catalytic activity is fine-tuned using two functional units: the cluster core and the linkers. The atomic resolution of such catalysts allows tracing the reaction process experiments coupled with theory and structural analysis. Site-specific catalysis for Ag-pyz induced by metal cluster assembly and linker synergy can be accurately elucidated to dominate in the series. Taking advantage of the pyrazine linker due to its lower basicity and the isotropic nature of inter-cluster interactions in Ag-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.
金属纳米团簇（NCs）在电化学研究中展现出作为催化剂的潜力，能在原子层面深入了解反应机理。然而，要构建一个对其机理有分子层面理解的集成催化剂仍然困难重重，尤其是在银团簇组装体方面。在本研究中，我们表明原子精确的银团簇组装体Ag-py、Ag-pyz、Ag-bpy、Ag-bpa、Ag-azopy（其中Ag = 二级结构单元，Py = 吡啶，pyz = 吡嗪，bpy = 4,4'-联吡啶，bpa = 1,2-双(4-吡啶基)乙烷，azopy = 4,4'-偶氮吡啶）可作为展示析氢反应（HER）的范例，其中催化活性通过两个功能单元进行微调：团簇核心和连接体。此类催化剂的原子分辨率使得能够通过实验结合理论和结构分析来追踪反应过程。由金属团簇组装和连接体协同作用诱导的Ag-pyz的位点特异性催化作用在该系列中占据主导地位，这一点可以得到准确阐释。利用吡嗪连接体较低的碱性以及Ag-pyz中团簇间相互作用的各向同性，它展现出增强的催化活性以及在硫位点的选择性氢吸附，与该系列中的其他物质不同，其效率高出近五倍。这项关于一系列银团簇组装体的研究提供了一个重要的结构模型，以理解催化剂的活性位点和活性，进一步推动基于功能团簇的组装体的发展。
