Enhancement of quaternary nitrogen doping of graphene oxide via chemical reduction prior to thermal annealing and an investigation of its electrochemical properties

Abstract

A simple and efficient method to enhance the quaternary nitrogen doping (N-doping) of graphene has been demonstrated. Recent studies have shown that quaternary N in the graphene network provides more efficient electrocatalytic activity. Therefore, a novel strategy to enhance the quaternary N-doping is currently in high demand. The strategy employed in this work was to modify graphene oxide (GO) prior to thermal annealing so as to provide a more efficient structure for quaternary N doping. GO was first chemically reduced with hydrazine to substantially increase the formation of C]C bonds and simultaneously decrease the atomic oxygen concentration. The reduced graphene oxide (RGO) was then annealed in the presence of NH 3 . Although N-doping via the replacement of oxygen is preferred, the probability of carbon being substituted with N dopants in the graphitic structure of RGO could increase due to the relatively higher content of C]C when compared to the atomic oxygen concentration. In addition, due to the decreased atomic oxygen concentration, the electro-conductivity was enhanced. Cyclic voltammograms (CVs) of 5 mM K 3 Fe(CN) 6 and 2 mM H 2 O 2 were used to examine the electrochemical response of the quaternary N-maximized RGO. An improvement in electrocatalytic reduction and a higher electro-conductivity were confirmed based on an analysis of the obtained CVs.

Improved Electrochemical Performance of FeF3 by Inlaying in a Nitrogen‐Doped Carbon Matrix

“…[35][36][37][38][39][40][41] Furthermore, the last fitting peak appeared in different locations. [26,51] Moreover, the obvious peaks around 1064 and 1401 cm À 1 in FC0 and FCN are assigned to the CÀ C stretching bands [52][53][54] and in plane vibration of CÀ H, [55][56][57][58][59] respectively. [35,38] And the one located at 285.6 eV in FCN was indexed to CÀ O/CÀ N bonds, which due to sp 2 C atoms bonded to N. [36,42,43] Similar to the characterization results of C1s, the signal about N was detected only in FCN, which at binding energy of 400.1 eV and corresponding to pyrrolic N (nitrogen in a five-atom heterocyclic ring).…”

“…[46,[48][49][50] Furthermore, the bending vibration of OÀ H also observed at 1614 cm À 1 . [26,51] Moreover, the obvious peaks around 1064 and 1401 cm À 1 in FC0 and FCN are assigned to the CÀ C stretching bands [52][53][54] and in plane vibration of CÀ H, [55][56][57][58][59] respectively. The particular peak (1230 cm À 1 ) in FCN is considered to be derived from CÀ N stretching vibrations, which imply the nitrogen atoms were doped into the carbon skeleton.…”

Flexible and Mechanically Durable Asymmetric Supercapacitor Based on NiCo‐Layered Double Hydroxide and Nitrogen‐Doped Graphene Using a Simple Fabrication Method

“…The former showed the presence of defects in the graphitic lattice, while the G band was associated with the E 2g mode of sp 2 carbon domains . Generally, the I D / I G ratio is used to estimate the amount of defect lattices and degree of disorders in graphene . The introduction of nitrogen atoms could increase the quantity of defects, resulting in a higher intensity of the D band of graphene .…”

The effect of temperature on thermoelectric properties of n-type Bi2Te3 nanowire/graphene layer-by-layer hybrid composites

“…34 The presence of an A 1u peak clearly indicates that the symmetry of the crystal is broken in the Bi 2 Te 3 nanowires. [38][39][40] This indicates that the composite samples become more disordered at higher sintering temperatures, suggesting that the graphene is doped during sintering. 33 The Raman spectra in the graphene region (1100-2300 cm −1 ) of the composites sintered at different temperatures are shown in Fig.…”