Single Nanoparticle Electrochemistry

With the development of science and technology, electronic products and electronic devices are becoming miniaturization, such as nanocapacitor. So an analytical method which can be used to characterized nanomaterials with high selectivity, sensitivity, controllability should be developed urgently. Electrochemical analysis is an important branch of instrumental analysis. It’s more than two centuries since Volta created the first chemical battery at the early 19th century. electrochemical techniques have been involved in various fields of modern life due to its fast analysis speed, high selectivity, convenient operation, low cost, amenable miniaturization, high sensitivity, less sample consumption, etc. Currently, the research of electrochemical methods have been moving in the direction of a more miniaturization, how to improve the detection sensitivity and signal to noise ratio as well as realize the simplicity and controllable of research is a challenging issue to the modern electrochemical fields.In this paper, the nanoparticles are detected with electrochemical technique on single particle level, founding that this method has various advantages. The main contents are summarized as follows:1 The as-prepared carbon fiber ultramicro disk electrode acted as working electrode. The electrochemical response of modified AuNPs was detected on the microelectrode. From the results, we can see that the electric quantity of modified nanoparticles will be increased distinctly when the nanoparticles impact with the inert microelectrode. Compared with the electrochemical responses of C-AuNPs and 1-pentanethiol-AuNPs on the microelectrode as well as the results of CV and EIS of the prepared nanoparticles, we can conclude that the large electric quantity caused by the delocalized electron on the aromatic ring which make the midified-nanoparticles conjugated well. Meanwhile increase the electron transfer rate greatly. Finally, a larger electric quantity can be achieved. By the slope of charge- square of radius of nanoparticles curve, we can obtain the electron number when the nanoparticles collision with the microelectrode. In addition, we can determine the concentration of NPs in the solution by the correlation of collision frequency and concentration of nanoparticles.2 The micro hanging mercury electrode was prepared and used as working electrode. The single particle response of the AgNPs was explored with reduction of H+ acting as an indicator reaction. The results showing that compared to the mercury electrode, the electron transfer of H+ will be faster on the silver electrode. That is to say the AgNPs can catalyze the reduction of the H+ efficiently. Moreover, the single AgNPs were characterized successfully. In addition, it is apt to renew for mercury electrode compared with the carbon fiber electrode, and it made the operation is faster and easier.3 Carbon fiber ultramicro disk electrode is used as working electrode in this section. The single particle response of the Pt/C was explored with the oxygen reduction reaction acting as an indicator reaction. The results showing that Pt/C present a prominent effect to oxygen reduction reaction. Moreover, a different current～time curve to the other research system was obtained in the experiment of single Pt/C particles.