Metal nanoclusters are an important class of materials for catalytic applications. Sub nanometer clusters are relatively less explored for their catalytic activity on account of undercoordinated surface structure. Taking this into account, we studied platinum-based sub nanometer clusters for their catalytic activity for oxygen reduction reaction (ORR). A comprehensive analysis with global optimization is carried out for structural prediction of the platinum clusters. The energetic and electronic properties of interactions of clusters with reaction intermediates are investigated. The role of structural sensitivity in the dynamics of clusters is unraveled, and unique intermediate specific interactions are identified. ORR energetics is examined, and exceptional activity for sub nanometer clusters are observed. An inverse size versus activity relationship is identified, challenging the conventional trends followed by larger nanoclusters. The principal role of atomicity in governing the catalytic activity of nanoclusters is illustrated. The structural norms governing the sub nanometer cluster activity are shown to be markedly different from larger nanoclusters.

中文翻译：

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原子性在铂亚纳米簇氧还原反应活性中的作用：全局优化研究

金属纳米团簇是一类重要的催化应用材料。由于表面结构不协调，亚纳米簇的催化活性研究相对较少。考虑到这一点，我们研究了铂基亚纳米簇对氧还原反应 (ORR) 的催化活性。对铂簇的结构预测进行了全局优化的综合分析。研究了簇与反应中间体相互作用的能量和电子特性。结构敏感性在集群动力学中的作用被解开，并确定了独特的中间特定相互作用。检查 ORR 能量学，并观察到亚纳米簇的异常活动。确定了反尺寸与活性的关系，挑战了更大纳米团簇所遵循的传统趋势。说明了原子性在控制纳米团簇催化活性中的主要作用。控制亚纳米团簇活性的结构规范与较大的纳米团簇明显不同。