Nitrogen-Doped Carbon Nanotubes: High Electrocatalytic Activity toward the Oxidation of Hydrogen Peroxide and Its Application for Biosensing

Abstract

This study compares the electrocatalytic activity of nitrogen-doped carbon nanotubes (NCNTs) with multiwalled carbon nanotubes (MWCNTs). Results indicate that NCNTs possess a marked electrocatalytic activity toward oxygen reduction reaction (ORR) by an efficient four-electron process in the alkaline condition, while the process of MWCNTs is through a two-electron pathway. Meanwhile, NCNTs show a very attractive electrochemical performance for the redox reaction of hydrogen peroxide (H2O2) and could be employed as a H2O2 sensor at a low potential of +0.3 V. The sensitivity of the NCNT-based biosensor reaches 24.5 microA/mM, more than 87 times that of the MWCNT-based one. Moreover, NCNTs exhibit striking analytical stability and reproducibility, which enables a reliable and sensitive determination of glucose by monitoring H2O2 produced by an enzymatic reaction between glucose oxidase/glucose or choline oxidase/choline at +0.3 V without the help of the electron mediator. The NCNT-based glucose biosensor has a linear range from 2 to 140 microM with an extremely high sensitivity of 14.9 microA/mM, and the detection limit is estimated to be 1.2 microM at a signal-to-noise ratio of 3. The results indicate that the NCNTs are good nanostructured materials for potential application in biosensors.

Exposure to Carbon Nanotubes Leads to Changes in the Cellular Biomechanics

“…[4] Their unique properties provide a tremendous potential for applications in fields as diverse as electronics, [5] aerospace industries, [6] sensors, [7] actuators, [8] or composites. [9] Based on their properties, researchers have also been exploring CNTs potential for biological and biomedical applications as drug delivery systems, [10] substrate for cells growth in tissue regeneration, [11] therapeutic cerasela-zoica…”

Nitrogen-doped carbon-embedded TiO2 nanofibers as promising oxygen reduction reaction electrocatalysts

“…These proposed pathways can be represented as follows [52,53]: The n values indicate that doping with nitrogen atoms enhances the electron-donor functionality of N-TiO 2 @C-0.75, and the strength of the O−O bond is reduced because of the nitrogen/oxygen bonding, thereby improving its ORR activity [54].…”

Synthesis and electrochemical applications of nitrogen-doped carbon nanomaterials

“…The N-CNTs produced from the different N-sources using a single-step CVD process having much higher nitrogen content and more distortion properties express a better ORR catalytic performance in the acidic electrolytes [56]. The comparable analysis of the N-doped MWCNT and the undoped CNT showed a remarkable enhanced activity and efficient four-electron transfer for H 2 O 2 in the former case with 87 times more sensitivity making it a good H 2 O 2 sensor [126]. The doped CNTs can be used as platforms for the multiple derivatization by loading their surface with other therapeutic agents (treatment), fluorescent, magnetic, or radionuclide probes (tracking), active recognition moieties (targeting), and with nanoparticles.…”

“…The N-CNT synthesized in the metal free environment from melamine exhibited an excellent catalytic activity for oxygen reduction in the fuel cells, comparable to the traditional platinum-based catalysts. The four-and twoelectron combined pathway, in the case of the N-CNTs as a catalyst, exhibits an excellent selectivity in the ORR, with no visible response to methanol oxidation in competition to the Pt-C catalysts [5], and the two-electron pathway for the undoped MWCNTs could be use to generate the H 2 O 2 sensor even at a low potential of +0.3 V [126].…”