Fourier-Transformed Alternating Current Voltammetry (FTacV) for Analysis of Electrocatalysts

Abstract

Electrocatalysts play a critical role in energy technologies, but the development of active, efficient, and durable catalysts is impeded by the lack of methodologies to deconvolute the complex interplay between various aspects influencing the activity of the catalysts, e.g., the number of active sites, turnover frequency, and the reaction pathways. Fourier-transformed alternating current voltammetry (FTacV) is an emerging tool for the analysis of electroactive species and has been successfully applied to a variety of reactions such as the oxygen reduction reaction, oxygen evolution reaction, carbon dioxide reduction reaction, hydrogen evolution reaction, and hydrogen oxidation reaction. The harmonics generated from FTacV measurements neatly detect underlaying processes not visible by other, more commonly employed techniques for analysis of electrocatalysts, such as the rotating disc electrode and dc voltammetry. The harmonic components enable separating overlapping processes based on differences in kinetics or linearity of response. This paper presents a review of FTacV applied for the analysis of electrocatalysts. It highlights the importance of determining the electrochemically active site density (EASD) to decipher the intrinsic activity of a catalyst and discusses the use of FTacV in dynamic determination of the EASD over the course of a catalyst's working life, as well as the use of FTacV to understand intricate catalytic processes.