Evaluation of the Covalent Functionalization of Carbon Nano-Onions with Pyrene Moieties for Supercapacitor Applications

Abstract

Herein, we report the surface functionalization of carbon nano-onions (CNOs) through an amidation reaction that occurs between the oxidized CNOs and 4-(pyren-4-yl)butanehydrazide. Raman and Fourier transform infrared spectroscopy methods were used to confirm the covalent functionalization. The percentage or number of groups in the outer shell was estimated with thermal gravimetric analysis. Finally, the potential applications of the functionalized CNOs as electrode materials in supercapacitors were evaluated by cyclic voltammetry and electrochemical impedance spectroscopy. Functionalization increased the specific capacitance by approximately 138% in comparison to that of the pristine CNOs, while acid-mediated oxidation reduced the specific capacitance of the nanomaterial by 24%.

Covalent functionalization of carbon materials with redox-active organic molecules for energy storage

“…The CNO-Pyr electrodes exhibited 99% retention from its initial value after 1000 cycles. 140 The functionalization of carbon materials through an amidation reaction is stable under electrochemical conditions. The reason for the high stability of amide bonds is also discussed in section 3.1 (Table 5).…”

Mesoporous onion-like carbon nanostructures from natural oil for high-performance supercapacitor and electrochemical sensing applications: Insights into the post-synthesis sonochemical treatment on the electrochemical performance

“…It is also observed that the vertical line in the low-frequency region of a-OLCs approaches 90° in comparison to the s-OLCs. This sharp increase at low frequency clearly indicates the enhanced capacitive behavior of a-OLCs [49] .…”

Electrochemical Stability of Rhodium–Platinum Core–Shell Nanoparticles: An Identical Location Scanning Transmission Electron Microscopy Study

“…Additionally, a peak in the hydrogen underpotential deposition region is also seen. During the potential cycles, the cyclic voltammetry curves flatten progressively, and after 10 000 cycles only capacitive current can be observed, which can be attributed to the carbon support . This is indicative of a loss of active catalyst during the potential cycles, which could be caused by the common degradation mechanisms of fuel cell catalysts (particle dissolution, agglomeration, Ostwald ripening, and particle detachment from the carbon support).…”