Perspectives on electron transfer kinetics across graphene-family nanomaterials and interplay of electronic structure with defects and quantum capacitance
Abstract This perspective presents a combined experimental-theory investigation of the mechanistic outer-sphere electron transfer (OS-ET) kinetics in an adiabatic regime for a cornerstone electrochemical reaction, fundamental to efficient energy interconversion as in electrochemical double layer sup...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Nature Portfolio
2025-06-01
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| Series: | Scientific Reports |
| Subjects: | |
| Online Access: | https://doi.org/10.1038/s41598-025-04357-x |
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| Summary: | Abstract This perspective presents a combined experimental-theory investigation of the mechanistic outer-sphere electron transfer (OS-ET) kinetics in an adiabatic regime for a cornerstone electrochemical reaction, fundamental to efficient energy interconversion as in electrochemical double layer supercapacitors, across graphene-family nanomaterials (GFNs) ranging from pristine graphene to nitrogen-doped graphene aerogel and the novel laser-induced graphene. Using scanning electrochemical microscopy (SECM) operating in feedback mode and co-located spectroscopy, the ET rate constant, k 0 (or k ET, cm/s) was quantified while imaging electroactivity of potassium hexacyanoferrate (III/IV) [Fe (CN) 6 4−/3−] or ferrocene methanol [Fc 0 /Fc +] redox probe yielding unexpected trends. We examined factors affecting the kinetic rate constant, rationalized through a physical model and parameterized using density functional theory by incorporating defects and dopants. We attributed the improved kinetic rates (0.01–0.1 via SECM) compared with ensemble-averaged method (0.001–0.01 cm/s) to point-like topological defects in basal plane (number density ~ 1012/cm2), oxygen functional groups (C/O ratio: 4:1–12:1), nitrogen doping, and edge plane hydrogen-bonding sites (density: 0.1–1.0 μm−1), altering the electronic structure factored into available density of states near Fermi level (− 0.2 to + 0.2 eV), and quantum capacitance. We elucidated the ET kinetics tunability by engineering the electronic band structure, varying electrode potential, and morphological diversity. |
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| ISSN: | 2045-2322 |