Electrochemistry at Highly Oriented Pyrolytic Graphite (HOPG): Toward a New Perspective

This chapter is concerned with electrochemistry at, and of, highly oriented pyrolytic graphite (HOPG), a material that has been studied intermittently for several decades, but which is of enduring interest particularly as a comparison to other types of carbon electrodes. It presents an overview of the field, with a particular focus on recent work that allows key models of the HOPG electrochemistry to be assessed. Recent developments in scanning probe microscopy have provided new opportunities to determine the electrical and electrochemical characteristics of graphite with unprecedented detail and spatial resolution. These developments receive major attention in the chapter. An overview of the structure and electronic properties of graphite is provided. The chapter also assesses early electrochemical measurements at HOPG, which tended to rely on macroscopic measurements and correlations between different macroscopic quantities. It highlights that the new understanding of HOPG electrodes has implications for wider electrochemistry.