The effect of cyclic voltammetry speed on anion intercalation in HOPG

• Published in: Surface science Vol. 681; pp. 111 - 115
• Main Authors: Jagadeesh, M.S., Calloni, A., Denti, I., Goletti, C., Ciccacci, F., Duò, L., Bussetti, G.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.03.2019; Elsevier BV
• Subjects: Anions; Atomic force microscopy; Blister; Blistering; Blisters; Cyclic voltammetry; Electrolytes; Gas evolution; HOPG; Intercalation; Organic chemistry; Photoelectric emission; Photoemission spectroscopy; Swelling; Cyclic voltammetry; Blister; Photoemission spectroscopy; HOPG
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/j.susc.2018.11.009

•Perchlorate and sulfate anions are intercalated in HOPG by cyclic voltammetry (CV).•We observe blisters after CV only at a low scan speed (e.g. 25 meV/s).•We always detect intercalated ions, also after high speed CV (600 mV/s).•Blisters formation can be decoupled from anion intercalation. It is generally accepted that anion intercalation occurs when HOPG is kept at high electrochemical potentials in oxidant electrolytes, such as perchloric and sulfuric acids. The graphite surface undergoes a detriment, made also evident by the swelling of the uppermost layers (blisters formation) caused by gas evolution in standard electrochemical conditions (namely, by cycling the HOPG voltage at speeds up to 25 mV/s). Surface swelling is therefore considered as being indicative of anion intercalation. Recently, suppression of blister formation when the potential is swept at larger speeds (such as 600 mV/s) has been observed, raising the question as to whether this phenomenon might be able to suppress anion intercalation. In this work, by combining atomic force microscopy and X-ray photoemission spectroscopy, we unequivocally show that the HOPG electrode undergoes similar chemical modifications, regardless of the chosen electrochemical conditions and consequently of the morphological evolution at the surface. [Display omitted]