Evolution of the graphite surface in phosphoric acid: an AFM and Raman study

Yivlialin, Rossella; Bussetti, Gianlorenzo; Tommasini, Matteo; Bassi, Andrea; Casari, Carlo Spartaco; Passoni, M.; Ciccacci, Franco; Duó, Lamberto; Castiglioni, Chiara

doi:10.3762/bjnano.7.180

Cited by 22 publications

(18 citation statements)

References 27 publications

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“…Similar structures were previously observed on HOPG anodes at the initial stages of electrochemical oxidation in the presence of electrolytes capable of intercalating graphite (i.e., aqueous solutions of KNO 3 [ 15 ], LiClO 4 , (NH 4 ) 2 SO 4 , HNO 3 , H 2 SO 4 ) [ 16 – 17 ]. The electrochemical oxidation of graphite in H 3 PO 4 solutions resulted in the formation of the corroded carbon layers on the electrode surface [ 18 ].…”

Section: Resultsmentioning

confidence: 99%

Blister formation during graphite surface oxidation by Hummers’ method

Синицына¹,

Мешков²,

Grigorieva³

et al. 2018

Beilstein J. Nanotechnol.

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Graphite oxide has a complex structure that can be modified in many ways to obtain materials for a wide range of applications. It is known that the graphite precursor has an important role in the synthesis of graphite oxide. In the present study, the basal-plane surface of highly annealed pyrolythic graphite (HAPG) was oxidized by Hummers’ method and investigated by Raman spectroscopy and atomic force microscopy. HAPG was used as a graphite precursor because its surface after cleavage contains well-ordered millimeter-sized regions. The treatment resulted in graphite intercalation by sulfuric acid and blister formation all over the surface. Surprisingly, the destruction of the sp2-lattice was not detected in the ordered regions. We suggest that the reagent diffusion under the basal plane surface occurred through the cleavage steps and dislocations with the Burgers vector parallel to the c-axis in graphite.

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Section: Resultsmentioning

confidence: 99%

Blister formation during graphite surface oxidation by Hummers’ method

Синицына¹,

Мешков²,

Grigorieva³

et al. 2018

Beilstein J. Nanotechnol.

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“…In particular, to gain insight into the electrochemical behavior of the Gr/Ni system, we compare results acquired from i) highly The HOPG electrode properties, when immersed in diluted sulfuric acid, have been widely investigated. [15][16][17][18][19][20][21][22][23][24] In Figure 1, we report a traditional CV from cathodic to anodic EC regions where the Faradaic current, flowing thorough the HOPG electrode, is measured as a function of the applied EC potential referred to the standard hydrogen electrode (SHE). The current enhancement above 1.70 V (anodic regime) is due to oxygen evolution.…”

Section: Toc Graphicsmentioning

confidence: 99%

CVD Graphene/Ni Interface Evolution in Sulfuric Electrolyte

et al. 2018

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Systems comprising single and multilayer graphene deposited on metals and immersed in acid environments have been investigated, with the aim of elucidating the mechanisms involved, for instance, in hydrogen production or metal protection from corrosion. In this work, a relevant system, namely chemical vapor deposited (CVD) multilayer graphene/Ni (MLGr/Ni), is studied when immersed in a diluted sulfuric electrolyte. The MLGr/Ni electrochemical and morphological properties are studied in situ and interpreted in light of the highly oriented pyrolytic graphite (HOPG) electrode behavior, when immersed in the same electrolyte. Following this interpretative framework, the dominant role of the Ni substrate in hydrogen production is clarified.

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“…The most relevant morphological change on the crystal surface after the graphite intercalation is the formation of blisters [17,18]. The latter, bubble-like circular structures (with lateral sizes within hundreds of nm and up to the micrometer length scale; height above tens of nm) which swell the HOPG basal plane, are generally interpreted as a consequence of the evolution of gaseous molecular species (CO, CO2, and O2) during the oxidative process [20][21][22][23]. The presence of such gases was recently detected by a mass-spectrometer just placed above the electrode surface [24].…”

Section: Introductionmentioning

confidence: 99%

“…A similar experimental effort is now wished for a more local chemical analysis of the intercalation process. To this goal, Raman spectroscopy has been initially exploited allowing an in-situ characterization during the EC reaction [23]. However, in a very recent work, we employed time-of-flight secondary ion mass spectrometry (ToF-SIMS) technique proving that a more sensitive analysis of the chemical species present on the HOPG electrode surface after the first intercalation stage is possible despite only ex-situ measures are possible [30].…”

Section: Introductionmentioning

confidence: 99%

Stratigraphic analysis of intercalated graphite electrodes in aqueous inorganic acid solutions

et al. 2021

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A detailed stratigraphic investigation of the intercalation mechanism when graphite electrodes are immersed inside diluted perchloric (HClO4) and sulfuric (H2SO4) electrolytes is obtained by comparing results when graphite crystals are simply immersed in the same acid solutions. By combining time-of-flight secondary ion mass spectrometry (ToF-SIMS) and in-situ atomic force microscopy (AFM), we provide a picture of the chemical species involved in the intercalation reaction. The depth intensity profile of the ion signals along the electrode crystal clearly shows a more complex mechanism for the intercalation process, where the local morphology of the basal plane plays a crucial role. Solvated anions are mostly located within the first tens of nanometers of graphite, but electrolytes also diffuse inside the buried layers for hundreds of nanometers, the latter process is also aided by the presence of mesoscopic crystal defects. Residual material from the electrolyte solution was found localized in well-defined circular spots, which represent preferential interaction areas. Interestingly, blister-like micro-structures similar to those observed on the highly oriented pyrolytic graphite (HOPG) surface were found in the buried layers, confirming the equivalence of the chemical condition on the graphite surface and in the underneath layers.

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Evolution of the graphite surface in phosphoric acid: an AFM and Raman study

Cited by 22 publications

References 27 publications

Blister formation during graphite surface oxidation by Hummers’ method

Blister formation during graphite surface oxidation by Hummers’ method

CVD Graphene/Ni Interface Evolution in Sulfuric Electrolyte

Stratigraphic analysis of intercalated graphite electrodes in aqueous inorganic acid solutions

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