Tracking the surface structure and the influence of cations and anions on the double-layer region of a Au(111) electrode
Adnan, Ariba (Leiden University)
Behjati, Saeid (Leiden University)
Félez-Guerrero, Núria (Universitat Autònoma de Barcelona. Departament de Química)
Ojha, Kasinath (Leiden University)
Koper, Marc T. M. (Leiden University)

Data:	2024
Resum:	We examined the electric double-layer (EDL) of a Au(111) electrode in a dilute perchloric acid solution using a combination of capacitance measurements and in situ scanning tunnelling microscopy under electrochemical conditions (ECSTM). The "camel-shaped" capacitance curve of the EDL is studied with different cations and anions, including their impact on the potential of zero charge (PZC). We show that the ECSTM images of thermally reconstructed and of the potential-induced surface reconstruction of Au(111) in perchloric acid electrolyte resemble previous work in sulphuric acid, displaying a herringbone pattern for a thermally reconstructed surface. Once the reconstruction is lifted, the Au(111) forms islands with an average of 1 atomic step height. When the potential is lowered below that of the PZC, the potential-induced surface reconstruction results in a more disoriented pattern than the thermally reconstructed surface. ECSTM images at different potentials are correlated with the voltammogram to understand the time and potential dependence of the surface. This correlation has led to the development of a potential window technique that can be used to reveal the surface structure of Au(111) based on observing the changes in PZC in the voltammogram. This method provides an indirect approach to understanding the surface structure without always relying on ECSTM. From the voltammogram, we also observed that anions (SO 2-, CHSO -, ClO -, F -) interact more strongly with the Au(111) surface than the alkali cations. The cation capacitance peak shape does not depend strongly on the identity of the alkali metal cation (Li +, Na +, K +). However, the anion capacitance peak depends strongly on the anion identity. It suggests that some level of specific adsorption cannot be excluded, even for anions that are traditionally not considered to adsorb specifically (perchlorate, fluoride). Electric double-layer capacitance plots on Au(111) are studied to better understand the role of water, cations, and anions, coupled with in situ scanning tunnelling microscopy under electrochemical conditions (ECSTM) to track the mobile surface.
Ajuts:	European Commission 101019998
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Publicat a:	Physical chemistry chemical physics, Vol. 26 (August 2024) , p. 21419-21428, ISSN 1463-9084

DOI: 10.1039/d4cp02133a
PMID: 39086202

10 p, 2.5 MB

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