Macroporous Graphene Frameworks for Sensing and Supercapacitor Applications

• Published in: Advanced functional materials 2022-10, Vol.32 (42), p.n/a
• Main Authors: Mohamed, Nahla B., El‐Kady, Maher F., Kaner, Richard B.
• Format: Article
• Language: English
• Subjects: Activated carbon; Additives; Ascorbic acid; Biomolecules; Capacitance; charge storage; Chemical sensors; Dopamine; Electrical properties; Electrodes; Graphene; graphene frameworks; Ions; Materials science; Selectivity; sensors; Sheets; Supercapacitors; Surfactants; Uric acid
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202203101

3D architectures based on graphene have triggered a great deal of interest in energy, sensing, and environmental applications. This work describes, a simple electrochemical approach for the direct deposition of a functionalized graphene framework by utilizing electrostatic interactions between graphene oxide (GO) and a cationic surfactant. The surfactant improves the adsorption of GO sheets on the electrode surface, allowing the integration of individual graphene sheets into 3D structures with large electrochemically active surface area. Without using binders or conductive additives, the current approach leads to supercapacitors with high specific capacitance (320 F g−1) and areal capacitance (≈400 mF cm−2 for two electrode cells with single‐sided coatings), which compares favorably to commercial activated carbon supercapacitors. Moreover, the supercapacitors demonstrate low internal resistance (≈1 Ω cm−2), excellent cycling stability (no loss observed after 10 000 cycles) while also maintaining superior rate capability. In another application, these frameworks  were successfully implemented as an electrochemical sensor for the simultaneous determination of small biomolecules including ascorbic acid, dopamine and uric acid with high sensitivity, selectivity and reproducibility. This work provides a simple, yet effective, strategy for the fabrication of macroporous electrodes with superior chemical, structural, and electrical properties that are desirable for a broad range of applications. This study describes a simple strategy for the direct deposition of macroporous graphene films onto conductive substrates for use in electrochemical applications. The result is a 3D graphene framework with a highly effective surface area, which is successfully applied in the construction of fast and reliable supercapacitors and for the simultaneous analysis of various biomolecules with high sensitivity and selectivity.