Potential-dependent current traces were first observed for the same sized nanoparticles (NPs) during the dynamic electro-oxidation process of single AgNPs. In this work, we demonstrated that the motion trajectories of NPs, coupled with electrochemical kinetics parameters, qualitatively predicted from the series of the experimentally observed current traces obtained single AgNPs collision behaviors. Based on the Poisson-Boltzmann equation for a general electrochemical reaction, a rate constant of Ag oxidation could be further estimated to be 1 × 10 mol·cm·s for electron transfer between AgNPs and the Au electrode by comparing the experimental results. Our method provided a meaningful attempt to test electron transfer kinetics and motion behaviors of single NPs using the high-resolution electrochemical signal.

nanomaterials are synthesized at relatively low temperature (80 C) and with a short hydrothermal treatment time (3 h) using glucose (Glc) as a catalyst. Contrary to previous studies, it is possible to synthesize one of the Ag x Mo y O z binaries at 80 C by altering the pH of the reaction media in the presence of glucose. In addition, further experiments indicate that Ag/h-MoO 3 , Ag 2 Mo 2 O 7 and Ag/b-MoO 3 can be convertedto Ag/a-MoO 3 which can also be synthesized from a reaction involving ammonium heptamolybdate tetrahydrate and AgNO 3 at room temperature using cysteamine in both methods. Characterization with UV-Vis, XRD and Raman spectroscopy reveals high purity of as-synthesized product. These synthesized products are finally used to fabricate SERS substrates by coating a silicon wafer with a mixture of silver nanoparticles (Ag NPs) and Ag x Mo y O z (Si@Ag/Ag x Mo y O z ). The results show a good sensitivity and stability. In addition, it is also found that the SERS activity of Si

An ultrasensitive photoelectrochemical method for achieving real-time detection of single nanoparticle collision events is presented. Using a micrometer-thick nanoparticulate TiO -filmed Au ultra-microelectrode (TiO @Au UME), a sub-millisecond photocurrent transient was observed for an individual N719-tagged TiO (N719@TiO ) nanoparticle and is due to the instantaneous collision process. Owing to a trap-limited electron diffusion process as the rate-limiting step, a random three-dimensional diffusion model was developed to simulate electron transport dynamics in TiO film. The combination of theoretical simulation and high-resolution photocurrent measurement allow electron-transfer information of a single N719@TiO nanoparticle to be quantified at single-molecule accuracy and the electron diffusivity and the electron-collection efficiency of TiO @Au UME to be estimated. This method provides a test for studies of photoinduced electron transfer at the single-nanoparticle level.

The pace of nanomaterial discovery for high-performance electrocatalysts could be accelerated by the development of efficient screening methods. However, conventional electrochemical characterization via drop-casting is inherently inaccurate and time-consuming, as such ensemble measurements are serially performed through nanocatalyst synthesis, morphological characterization, and performance testing. Herein, we propose a rapid electrochemical screening method for bimetallic electrocatalysts that combines nanoparticle (NP) preparation and performance testing at the single NP level, thus avoiding any inhomogeneous averaging contribution. We employed single NP collision electrochemistry to realize in situ electrodeposition of a precisely tunable Pt shell onto individual parent NPs, followed by instantaneous electrocatalytic measurement of the newborn bimetallic core–shell NPs. We demonstrated the utility of this approach by screening bimetallic Au–Pt NPs and Ag–Pt NPs, thereby exhibiting promising electrocatalytic activity at optimal atomic ratios for methanol oxidation and oxygen reduction reactions, respectively. This work provides a new insight for the rapid screening of other bimetallic electrocatalysts.

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.