Facile Synthesis of Nitrogen-Doped Graphene–Ultrathin MnO₂ Sheet Composites and Their Electrochemical Performances

Abstract

Nitrogen-doped graphene-ultrathin MnO2 sheet composites (NGMCs) were prepared through a one-step hydrothermal method at low temperature (120 °C). Ultrathin MnO2 sheets were well-dispersed and tightly anchored on graphene sheets, which were doped with nitrogen simultaneously. NGMCs electrode exhibited enhanced capacitive performances relative to those of undoped graphene-ultrathin MnO2 sheets composites (GMCs). As the current density increased from 0.2 to 2 A/g, the capacitance of NGMCs still retained ~74.9%, which was considerablely higher than that of GMCs (27%). Moreover, over 94.2% of the original capacitance was maintained after 2000 cycles, indicating a good cycle stability of NGMCs electrode materials.

Co3O4/nitrogen-doped graphene/carbon nanotubes: An innovative ternary composite with enhanced electrochemical performance

“…The suitable defects of graphene derived from the N-configuration of NG sheets can not only provide more active sites for electron storage but also enhance binding energies with ions in the electrolyte. Because larger binding energy leads to a larger number of ions being accommodated on the electrode surface, the enhancement of binding energy would improve the capacitance [18]. Owing to the excellent performance of NG, the composites are able to serve as a promising candidate for high-capacitance electrodes materials for supercapacitor.…”

“…The atomic percentage of doped nitrogen is about 3.8 at.% and 68% N atoms doped into the graphene lattice belong to the pyrrolic N atoms. The pyrrolic nitrogen plays key roles in the improved capacitances of the Co 3 O 4 /NG/CNTs, because of their higher charge mobility in graphene, which leads to better electrondonor characteristics and enhance carbon catalytic activity in electron transfer reactions [18]. Therefore, the Co 3 O 4 /NG/CNTs are expected to improve the rate performance of electrode material in supercapacitor.…”

“…This result demonstrates that the Co 3 O 4 /NG/CNTs have better cycling stability than the other two electrodes. The origin of good cycling stability may come from two aspects: Firstly, the binding energy between Co 3 O 4 particles and N-doped graphene sheets will be enhanced due to the extra active and nucleation sites provided by N-doping (especially by pyrrolic N-doping) [18,27]. Secondly, CNTs embedded into N-doped graphene sheets serve as a structural buffer for the large volume expansion-contraction during the redox reaction process.…”

Simple synthesis of ZnO nanoparticles on N-doped reduced graphene oxide for the electrocatalytic sensing ofl-cysteine

“…3c), the broad peak could be tted into four peaks at 398.5, 399.5, 401.3 and 404.0 eV, which are ascribed to the pyridine N, pyrrolic or amine moieties N, graphitic N and weak oxidized N. 30 The pyridinic N in ZnONPs/N-rGO could provide a pair of electrons for the p-conjugated rings, leading to the properties of electron donor for graphene-based materials; the pyrrolic N has rapid charge mobility in N-rGO due to its excellent electron donor properties. 28,31 Notably, the amount of N incorporated in the nanocomposite was found to be 5.49% with a relatively high doping content. The high-resolution scan of Zn 2p in Fig.…”

Anchoring High-dispersed MnO 2 Nanowires on Nitrogen Doped Graphene as Electrode Materials for Supercapacitors

“…In a recent report, nitrogen doped graphene and ultrathin MnO 2 sheet composites were synthesized by one-step hydrothermal method at 120 ºC [30]. However, this in situ reduction with concomitant nitrogen atoms doping is uncontrollable.…”