Facile green synthesis of carbon quantum dots and biomass-derived activated carbon from banana peels: synthesis and investigation

We introduce a simple, low-cost, and environment friendly method to obtain high-fluorescence carbon dots and activated carbon via a one-step hydrothermal process using banana peels. The dispersion of carbon dots generated strong, bright-blue photoluminescence (average diameter 3-6 nm), which could be further used in biosensing, electronics, and catalysis applications research. Moreover, the precipitation accumulated at the bottom of the hydrothermal process contained activated carbon with a highly porous structure and large specific surface area (294.6 m(2) g(-1)), which could be used as a supercapacitor electrode. The three-electrode cell exhibited excellent capability and stability of the activated carbon as the working electrode in various aqueous electrolytes, with a high specific capacitance (199 F g(-1)) in an aqueous electrolyte (1-M KOH) and a high energy density of 54.15 Wh kg(-1)at a current density of 0.5 A g(-1). Thus, based on the excellent characteristics of the carbon dots and the strong electrochemical properties of the activated carbon as an electrode material, the banana peels, as an abundant bioresource, can provide two excellent produces.

Automated summary

In this study, high-fluorescence carbon dots and activated carbon were obtained from banana peels using a one-step hydrothermal process. The carbon dots showed strong photoluminescence and can be used in biosensing, electronics, and catalysis applications research. The activated carbon collected at the bottom of the hydrothermal process exhibited excellent electrochemical properties and can be used as a supercapacitor electrode.