Principal Component Analysis as a Tool for Electrochemical Characterization of Modified Electrodes: A Case Study

Abstract

Characterizing electrodes surface is a mandatory step in developing any electrochemical methodology, especially when electrode modification is performed. One or two electrochemical techniques are often used, and their results are evaluated separately, leading to the loss of valuable information. Principal Component Analysis (PCA) is presented as an appealing strategy to optimize the electrochemical characterization of the modified-electrode’s surface. The developed strategy was applied for the characterization of glassy carbon (GC) electrode modified with reduced graphene oxide (GC/RGO), RGO with gold nanoparticles (GC/RGO/AuNP), and RGO with copper nanoparticles (GC/RGO/CuNP). The electrochemical characterization techniques used were differential pulse voltammetry (DPV), linear scan voltammetry (LSV), and electrochemical impedance spectroscopy (EIS). The PCA showed the data from the four electrodes separately, and it was possible to determine that the GC/RGO/AuNP electrode had the most efficient surface for charge transfer. By scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) experiments, the metal:RGO ratio was determined, and by normalizing the results with this ratio, GC/RGO/CuNP and GC/RGO/AuNP presented similar responses. With the proposed methodology, it was possible to evaluate simultaneously and straightforwardly all data, making this propose an innovative method for a robust electrochemical characterization based on usual electrochemical techniques.