Exploring the role of edges in surface functionalization and stability of plasma-modified carbon materials: Experimental and DFT insights

Effective surface functionalization of carbon nanomaterials plays a crucial role in various applications. We investigated the impact of edges on surface functionalization and stability of oxygen-modified carbon materials using a combination of experimental techniques and Density Functional Theory (D...

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Main Authors: Divya Kumar, Marek Białoruski, Witold Piskorz, Andrzej Kotarba
Format: Article
Language:English
Published: Elsevier 2024-12-01
Series:Applied Surface Science Advances
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Online Access:http://www.sciencedirect.com/science/article/pii/S266652392400076X
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author Divya Kumar
Marek Białoruski
Witold Piskorz
Andrzej Kotarba
author_facet Divya Kumar
Marek Białoruski
Witold Piskorz
Andrzej Kotarba
author_sort Divya Kumar
collection DOAJ
description Effective surface functionalization of carbon nanomaterials plays a crucial role in various applications. We investigated the impact of edges on surface functionalization and stability of oxygen-modified carbon materials using a combination of experimental techniques and Density Functional Theory (DFT) insights. Graphenic paper, highly oriented pyrolytic graphite (HOPG), and graphenic flakes were employed as model systems, with oxygen plasma treatment (generator power 100 W, oxygen pressure 0.2 mbar, exposure time 6 – 300 s) serving as the modification method. Surface morphology and chemical composition were characterized using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The results revealed the introduction of oxygen functional groups on the investigated carbon surfaces (up to 20 at % by XPS) whereas; the structural integrity of the materials remained intact upon plasma modification (SEM, Raman). Work function was used as a sensitive parameter for monitoring the surface changes (increase by ∼1.4 eV, 1.3 eV, and 1 eV for graphenic paper, HOPG, and graphenic flakes, respectively) while time-dependent measurements revealed distinct kinetic processes governing the decay of functionalization, highlighting the role of surface defects in post-plasma processes. DFT calculations provided molecular-level insights into the surface processes, elucidating the mechanisms underlying the diffusion of hydroxyls, their recombination, and water desorption. Since the calculated activation barrier for recombination on basal graphenic planes (∼1.0 eV) and edges (∼5.5 eV) are distinctly different, it can be thus concluded that the persistent functionalization is due to the surface edges. Our findings contribute to a deeper understanding of surface modification processes of carbon materials and offer rationales for the design of advanced functional nanomaterials with tailored surface properties.
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spelling doaj-art-2ecbc624cd4a493992dca77258c341772025-08-20T02:21:07ZengElsevierApplied Surface Science Advances2666-52392024-12-012410064810.1016/j.apsadv.2024.100648Exploring the role of edges in surface functionalization and stability of plasma-modified carbon materials: Experimental and DFT insightsDivya Kumar0Marek Białoruski1Witold Piskorz2Andrzej Kotarba3Corresponding authors.; Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, PolandFaculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, PolandCorresponding authors.; Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, PolandCorresponding authors.; Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, PolandEffective surface functionalization of carbon nanomaterials plays a crucial role in various applications. We investigated the impact of edges on surface functionalization and stability of oxygen-modified carbon materials using a combination of experimental techniques and Density Functional Theory (DFT) insights. Graphenic paper, highly oriented pyrolytic graphite (HOPG), and graphenic flakes were employed as model systems, with oxygen plasma treatment (generator power 100 W, oxygen pressure 0.2 mbar, exposure time 6 – 300 s) serving as the modification method. Surface morphology and chemical composition were characterized using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The results revealed the introduction of oxygen functional groups on the investigated carbon surfaces (up to 20 at % by XPS) whereas; the structural integrity of the materials remained intact upon plasma modification (SEM, Raman). Work function was used as a sensitive parameter for monitoring the surface changes (increase by ∼1.4 eV, 1.3 eV, and 1 eV for graphenic paper, HOPG, and graphenic flakes, respectively) while time-dependent measurements revealed distinct kinetic processes governing the decay of functionalization, highlighting the role of surface defects in post-plasma processes. DFT calculations provided molecular-level insights into the surface processes, elucidating the mechanisms underlying the diffusion of hydroxyls, their recombination, and water desorption. Since the calculated activation barrier for recombination on basal graphenic planes (∼1.0 eV) and edges (∼5.5 eV) are distinctly different, it can be thus concluded that the persistent functionalization is due to the surface edges. Our findings contribute to a deeper understanding of surface modification processes of carbon materials and offer rationales for the design of advanced functional nanomaterials with tailored surface properties.http://www.sciencedirect.com/science/article/pii/S266652392400076XOxygen plasmaCarbon materialsSurface functionalizationEdgesDFT molecular modeling
spellingShingle Divya Kumar
Marek Białoruski
Witold Piskorz
Andrzej Kotarba
Exploring the role of edges in surface functionalization and stability of plasma-modified carbon materials: Experimental and DFT insights
Applied Surface Science Advances
Oxygen plasma
Carbon materials
Surface functionalization
Edges
DFT molecular modeling
title Exploring the role of edges in surface functionalization and stability of plasma-modified carbon materials: Experimental and DFT insights
title_full Exploring the role of edges in surface functionalization and stability of plasma-modified carbon materials: Experimental and DFT insights
title_fullStr Exploring the role of edges in surface functionalization and stability of plasma-modified carbon materials: Experimental and DFT insights
title_full_unstemmed Exploring the role of edges in surface functionalization and stability of plasma-modified carbon materials: Experimental and DFT insights
title_short Exploring the role of edges in surface functionalization and stability of plasma-modified carbon materials: Experimental and DFT insights
title_sort exploring the role of edges in surface functionalization and stability of plasma modified carbon materials experimental and dft insights
topic Oxygen plasma
Carbon materials
Surface functionalization
Edges
DFT molecular modeling
url http://www.sciencedirect.com/science/article/pii/S266652392400076X
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AT witoldpiskorz exploringtheroleofedgesinsurfacefunctionalizationandstabilityofplasmamodifiedcarbonmaterialsexperimentalanddftinsights
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