Mass-transport-limited reaction rates and molecular diffusion in the van der Waals gap beneath graphene
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arXiv
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| Main Authors: | , , , , , , , , , |
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| Format: | Preprint |
| Published: |
2025
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| _version_ | 1866911551727861760 |
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| author | Mirdamadi, Hossein David, Jiří Wang, Rui Jiang, Tianle Wang, Yanming Vařeka, Karel Dymáček, Michal Bábor, Petr Šikola, Tomáš Kolíbal, Miroslav |
| author_facet | Mirdamadi, Hossein David, Jiří Wang, Rui Jiang, Tianle Wang, Yanming Vařeka, Karel Dymáček, Michal Bábor, Petr Šikola, Tomáš Kolíbal, Miroslav |
| contents | The confinement of molecules within the van der Waals (vdW) gap between a two-dimensional 2D material and a catalytic substrate offers a promising route toward the development of molecule-selective catalysts with increased reaction rates. However, identifying the kinetic limitations of such confined reactions remains challenging. Here, we employ an inverted wedding-cake configuration of multilayer graphene on platinum to study the dynamics of graphene etching in the vdW gap by various molecules (O2, H2, and CO), using in situ scanning electron microscopy. Under the experimental conditions explored (up to p = 1.4x10-3 Pa and T = 1000 °C), the etching reaction rates are limited by mass transport within the confined space. This limitation persists even for CO, despite its anomalously enhanced transport resulting from a significant lifting of the vdW gap. Reactive molecular dynamics simulations further reveal multiple etching pathways for CO, enabled by confinement within the vdW space. Once mass-transport limitations are overcome, the vdW gap acts as an effective nanoreactor, facilitating reaction pathways that would be otherwise inaccessible on a pristine surface without spatial confinement. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2507_07479 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Mass-transport-limited reaction rates and molecular diffusion in the van der Waals gap beneath graphene Mirdamadi, Hossein David, Jiří Wang, Rui Jiang, Tianle Wang, Yanming Vařeka, Karel Dymáček, Michal Bábor, Petr Šikola, Tomáš Kolíbal, Miroslav Mesoscale and Nanoscale Physics The confinement of molecules within the van der Waals (vdW) gap between a two-dimensional 2D material and a catalytic substrate offers a promising route toward the development of molecule-selective catalysts with increased reaction rates. However, identifying the kinetic limitations of such confined reactions remains challenging. Here, we employ an inverted wedding-cake configuration of multilayer graphene on platinum to study the dynamics of graphene etching in the vdW gap by various molecules (O2, H2, and CO), using in situ scanning electron microscopy. Under the experimental conditions explored (up to p = 1.4x10-3 Pa and T = 1000 °C), the etching reaction rates are limited by mass transport within the confined space. This limitation persists even for CO, despite its anomalously enhanced transport resulting from a significant lifting of the vdW gap. Reactive molecular dynamics simulations further reveal multiple etching pathways for CO, enabled by confinement within the vdW space. Once mass-transport limitations are overcome, the vdW gap acts as an effective nanoreactor, facilitating reaction pathways that would be otherwise inaccessible on a pristine surface without spatial confinement. |
| title | Mass-transport-limited reaction rates and molecular diffusion in the van der Waals gap beneath graphene |
| topic | Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2507.07479 |