Intrinsic Electrocatalytic Activity of Gold Nanoparticles Measured by Single Entity Electrochemistry

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.