The Distribution of Nucleation Activities: A New Local Perspective with Scanning Electrochemical Cell Microscopy

Abstract

Electrodeposition is a convenient strategy for the synthesis of functional nanostructures, for which electrochemical nucleation and growth (EN&G) processes need to be well understood [1]. As a heterogenous process, understanding the distribution of nucleation sites on a substrate is fundamental to relate the microscopic events to the macroscopic properties of the new deposit. In this work, we have explored the EN&G process on a glassy carbon substrate with a local electrochemical approach based on the Scanning Electrochemical Cell Microscopy (SECCM), using copper as a case of study [2]. Since the studies of EN&G are extremely sensitive to the state of the surface, the diversity of the nucleation process is revealed by performing hundreds of spatially resolved experiments on the heterogeneous surface of the glassy carbon [2,3]. The spatially-resolved characterization opens up the opportunity to correlate the electrochemical information to the local surface state, which can be modified with common surface pretreatments (i. e., polishing and preanodization). This unique perspective of the EN&G can help to deconvolute the individual contributions to the overall process, bringing forward information on nucleation sites that is unavailable with the conventional macroscopic approach.[1] J. Ustarroz, Current atomic-level understanding of electrochemical nucleation and growth on low-energy surfaces, Curr. Opin. Electrochem. 19 (2020) 144–152.[2] D.Torres, M. Bernal, J. Ustarroz, distribution of copper nucleation activities on glassy carbon: a new local perspective, to be submitted 2022[3] M. Bernal, D. Torres, S. Semsari, M. Čeh, K. Žužek Rožman, S. Šturm, J. Ustarroz, Diversity matters: Influence of surface heterogeneities in the electrochemical nucleation and dissolution of Au nanoparticles, under revision. Figure 1