Application of Electrochemical Impedance Spectroscopy for Evaluating Nanoparticle Agglomeration

Abstract

Metallic nanoparticles form dendrite assemblies when they are used as modifying agent in electrochemical reactions.1 These dendrites and the process of their formation can be visualized by application of imaging techniques such as scanning electron microscopy (SEM) and atomic force microscopy (AFM). Although these approaches provide local information about specific imaging points, electrochemical techniques offer a powerful means to probe the entire electrode surface. For instance, particle coagulation and dendrite formation drastically influence double-layer capacitance and charge-transfer resistance of modified electrodes. Consequently, variation of these parameters during electrochemical reactions can be probed by application of electrochemical impedance spectroscopy (EIS).2 In this work, a modified electrode was fabricated through electrophoretic deposition of copper sulfide nanoplates onto a detachable glassy carbon surface. Then a potential of –1.5 V vs. SCE was applied to a modified electrode for 2 h. Finally, the morphological evolution of the electrode was investigated by application of EIS and SEM methods. Moreover, a random-walk simulation was used to model the agglomeration process. The simulation results were compared to the morphology and EIS spectra of the modified electrode to correlate the simulation with physical information. References Manthiram, K.; Surendranath, Y.; Alivisatos, A. P., Dendritic Assembly of Gold Nanoparticles during Fuel-Forming Electrocatalysis. J. Am. Chem. Soc. 2014, 136, 7237–7240.Gao, S.; Sun, Z.; Liu, W.; Jiao, X.; Zu, X.; Hu, Q.; Sun, Y.; Yao, T.; Zhang, W.; Wei, S., Atomic layer confined vacancies for atomic-level insights into carbon dioxide electroreduction. Nat. Commun. 2017, 8, 14503–14509.