Ion Dynamics at the Carbon Electrode/Electrolyte Interface: Influence of Carbon Nanotubes Types

Abstract

Electrochemical quartz crystal microbalance (EQCM) and AC-electrogravimetry methods were employed to study ion dynamics in carbon nanotube base electrodes in NaCl aqueous electrolyte. Two types of carbon nanotubes, Double Wall Carbon Nanotube (DWCNT) and Multi Wall Carbon Nanotube (MWCNT), were chosen due to their variable morphology of pores and structure properties. The effect of pore morphology/structure on the capacitive charge storage mechanisms demonstrated that DWCNT base electrodes are the best candidates for energy storage applications in terms of current variation and specific surface area. Furthermore, the mass change obtained via EQCM showed that DWCNT films is 1.5 times greater than MWCNT films in the same potential range. In this way, the permselectivity of DWCNT films showed cation exchange preference at cathode potentials while MWCNT films showed anion exchange preference at anode potentials. The relative concentration obtained from AC-electrogravimetry confirm that DWCNT base electrodes are the best candidates for charge storage capacity electrodes, since they can accommodate higher concentration of charged species than MWCNT base electrodes.

Highly Ordered Graphene Polydopamine Composite Allowing Fast Motion of Cations: Toward a High‐Performance Microsupercapacitor

“…To confirm our hypothesis deconvoluting the total mass response to charged species and free solvent molecule contributions to the charge storage process, a verification approach consisting of the complementarity of the EQCM and ac-electrogravimetry was employed, following the procedure already described in literature. [28][29][30][31] From ac-electrogravimetry, the relative concentration changes of exchanged species, C i -C 0 , as a function of the applied potential can be obtained. This quantity is estimated from the integration of the concentration/potential TF, ΔC ΔE (𝜔), at low frequencies (Equation S5, Supporting Information).…”

“…To confirm our hypothesis deconvoluting the total mass response to charged species and free solvent molecule contributions to the charge storage process, a verification approach consisting of the complementarity of the EQCM and ac‐electrogravimetry was employed, following the procedure already described in literature. [ 28–31 ]…”

Hydrothermal Synthesis of a Graphene‐based Composite Enabling the Fabrication of a Current Collector‐free Microsupercapacitor with Improved Energy Storage Performance

“…The transfer order of the two cations as well as the participation of free water is consistent with ac-electrogravimetry measurements previously performed on carbon materials in similar electrolytes. [28][29][30][31] The interfacial transfer constants, Ki, of the different species involved in the charge compensation process as a function of the applied potential for rGO and rGO-PDA are shown in Figure S4. From this figure, it is clear that the three exchanged species transfer faster at the composite electrode interface, rGO-PDA, compared to that at the rGO.…”

Nafion-Immobilized Functionalized MWCNT-based Electrochemical Immunosensor for Aflatoxin B1 Detection

“…To further improve the detection sensitivity and enhance the analytical performance of the EC immunosensor, various nanomaterials are commonly introduced to modify the electrode surface for accelerating the charge transfer and improving the catalytic activity. , Among them, multiwall carbon nanotubes (MWCNTs), a kind of hollow and multilayer nanomaterials with a special SP 2 hybrid structure, , exhibit a large specific surface area, excellent conductivity, strong catalytic activity, and good biocompatibility, which can be utilized in the EC immunosensing platform to achieve remarkable electrical signal amplification for the ultrasensitive detection of trace mycotoxins. What’s more, MWCNTs modified with some functional groups are beneficial for uploading more recognition elements such as Abs to improve the detection specificity and sensitivity .…”