Scanning Tunneling Microscopy Observation of Sulfur Electrodeposits on Graphite Single Crystals

dc.creatorZubimendi, J. L.
dc.creatorSalvarezza, Roberto Carlos
dc.creatorVázquez, L.
dc.creatorArvia, Alejandro Jorge
dc.date1996
dc.date2021-10-13T00:19:59Z
dc.date.accessioned2023-07-15T03:41:55Z
dc.date.available2023-07-15T03:41:55Z
dc.identifierhttp://sedici.unlp.edu.ar/handle/10915/126521
dc.identifierhttps://pubs.acs.org/doi/pdf/10.1021/la940759m?rand=8l3p6czd
dc.identifierissn:0743-7463
dc.identifierissn:1520-5827
dc.identifier.urihttps://repositorioslatinoamericanos.uchile.cl/handle/2250/7466704
dc.descriptionThe early stages of sulfur deposit growth on highly oriented pyrolytic graphite (HOPG) caused by HS- electrooxidation in a neutral buffered solution have been investigated using electrochemical techniques and ex situ scanning tunneling microscopy (STM). In this system sulfur deposition has been observed at −0.80 V vs SCE, i.e. a potential more negative than the reversible potential for the HS-/S reaction. The charge density was equivalent to an average surface coverage by sulfur atoms θ ≅ 1/3 monolayer (ML). Ex situ atomic resolution STM images of the layer electrodeposited at −0.8 V show sulfur submonolayers and large uncovered HOPG domains. Sulfur electroadsorption layers appear as a diluted (√3×√3) surface phase with S atoms atop C atoms of the graphite hexagons and the S−S interatomic distance d(S−S) = 0.42 nm. Further addition of S atoms to a diluted sulfur phase resulted in the formation of sulfur trimers with three S atoms placed atop the three C atoms constituting the graphite hexagons. In this case d(S−S) = 0.24 nm. Neighbor trimers originate a filled hexagonal lattice. Ex situ STM images of overpotential deposited sulfur also show submonolayer sulfur domains with a second hexagonal (√3×√3)R30° sulfur lattice with d(S−S) = 0.42 nm. A further increase of θ produces either a new honeycomb lattice with d(S−S) = 0.24 nm or a rectangular lattice formed by rows of S atoms with d(S−S) = 0.21 nm and row separation d(S−S) = 0.37 nm.
dc.descriptionInstituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas
dc.formatapplication/pdf
dc.format2-11
dc.languagees
dc.rightshttp://creativecommons.org/licenses/by/4.0/
dc.rightsCreative Commons Attribution 4.0 International (CC BY 4.0)
dc.subjectCiencias Exactas
dc.subjectQuímica
dc.subjecthighly oriented pyrolytic graphite
dc.subjectscanning tunneling microscopy
dc.subjectgraphite single crystals
dc.titleScanning Tunneling Microscopy Observation of Sulfur Electrodeposits on Graphite Single Crystals
dc.typeArticulo
dc.typeArticulo


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