Understanding the real nature of the intrinsic electrocatalytic performance of the counter electrode is crucial for realizing high conversion efficiency of solar energy in photoelectric devices. However, owing to the average effects, a thorough insight into such electrocatalytic process remains challenging in ensemble measurements. Here, we realized the real‐time detection of electrocatalytic reduction of a single Au nanoparticle (NP) in sulfide/polysulfide redox electrolyte solution using single entity collision electrochemistry. Owing to the high‐sensitivity electrochemical measurement, size‐dependent electrocatalytic behaviors of polysulfide reduction were observed for single AuNP collision. Our approach allowed the electrocatalytic properties of AuNPs for polysulfide electrolyte reduction at the single NPs level to be quantified, and the turnover number as a function of particle size were further estimated. Our result has further pointed out the importance of NP size control in the electrocatalysis study.

中文翻译：

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单实体电化学法测定金纳米粒子的本征电催化活性

理解对电极的固有电催化性能的真实本质对于实现光电器件中太阳能的高转换效率至关重要。然而，由于平均效果，对这种电催化过程的透彻了解在整体测量中仍然具有挑战性。在这里，我们实现了使用单实体碰撞电化学技术实时检测硫化物/多硫化物氧化还原电解质溶液中单个金纳米颗粒（NP）的电催化还原。由于具有高灵敏度的电化学测量，对于单个AuNP碰撞，观察到了大小依赖的多硫化物还原的电催化行为。我们的方法允许量化AuNPs在单个NPs水平上对多硫化物电解质还原的电催化性能，并进一步估计了周转数与粒径的关系。我们的结果进一步指出了在电催化研究中NP尺寸控制的重要性。