Nitrogen-Enriched Carbon Nanofibers Derived from Polyaniline and Their Capacitive Properties

Abstract

Nitrogen-doped carbon materials derived from N-containing conducting polymer have attracted significant attention due to their special electrochemical properties in the past two decades. Novel nitrogen-enriched carbon nanofibers (NCFs) have been prepared by one-step carbonization of p-toluene sulfonic acid (P-TSA) doped polyaniline (PANI) nanofibers, which are successfully synthesized via the rapid mixing oxidative polymerization at room temperature. NCFs with diameters ranging from 100 nm to 150 nm possess a highly specific surface area of 915 m 2 g −1 and a relatively rich nitrogen content of 7.59 at %. Electrochemical measurements demonstrate that NCFs have high specific capacitance (172 F g −1 , 2 mV s −1 ) and satisfactory cycling stability (89% capacitance retention after 5000 cycles). The outstanding properties affirm that NCFs can be promising candidates for supercapacitor electrode materials. Interestingly, the carbonization of PANI opens the possibility to tailor the morphology of resulting nitrogen-enriched carbon materials by controlling the reaction conditions of PANI synthesis. products of PANI (15 wt % N, 79 wt % C) have been successfully employed in other articles as electrode materials [29][30][31][32][33][34][35][36]. However, most of the present reported PANI-derived carbon materials are irregular and agglomerate. Furthermore, the PANI-derived carbon materials by one-step carbonization usually have a low specific surface area while the chemical activation process is complex and increases costs. Recently, one-dimensional (1D) nanostructured PANI, such as nanofibers, nanotubes, nanowires, and nanorods, have attracted intensive attention for their unique structure, properties, and new potential applications [37][38][39][40][41][42]. Various methods, such as hard or soft template [32,39], interfacial polymerization [40], and rapid mixing polymerization, have been used to tailor the morphology of the products in the chemical oxidative polymerization. Compared with other methods, the rapid mixing polymerization method is the most common non-template route to produce PANI nanofibers owing to its simplicity, cost effectiveness, being environmental friendly, and pure production [43][44][45][46][47].Furthermore, the molecular structure and functional groups of doped acids also influence the morphology and structure of resulting PANI particles [28,41,[47][48][49][50][51][52]. Chutia's work investigates the effect of organic camphorsulfonic acid (CSA) and inorganic hydrochloric acid (HCl) on the structures and conductivity of polyaniline, and the discovery indicates that PANI nanorods doped with CSA produce more uniform and aligned structures [50]. Organosulfonic acid possessing long alkyl-chain sulfonic acids, such as p-toluenesulfonic acid (P-TSA), β-naphtalenesulfonic acid (NSA), camphorsulfonic acid (CSA), and dodecyl benzene sulfonic acid (DBSA), have already been explored by some researchers [49,51]. P-TSA (the molecular structural formula is p-CH 3 C 6 H 4 SO 3 H) is a non-oxidizing organic acid, so...

Synthesis of Benzoxazine-Based N-Doped Mesoporous Carbons as High-Performance Electrode Materials

“…In our investigation, the heteroatom was introduced using benzoxazine as a carbon precursor. The benzoxazine-based porous carbon material introduces various organic elements, such as oxygen and nitrogen [23][24][25]. Meanwhile, the high surface area and ordered porous structure of electrode materials are also important factors that affect the performance of supercapacitors.…”

Catalytic Ozonation of Ibuprofen in Aqueous Media over Polyaniline–Derived Nitrogen Containing Carbon Nanostructures

“…Our results show that the N + /N ratio, which evaluates the doping level of the polymer, is ~37% (Table 2) [59][60][61]. In the case of PANI 900, the chemical state of the N atom in the carbon lattice, from the N1s high-resolution spectrum, can be identified as follows: pyridinic nitrogen, pyrrolic nitrogen, quaternary nitrogen, and pyridine N-oxide [62,63]. From N1s XPS spectra of PANI 900, we identify pyridinic nitrogen at a binding energy of ~398.4 eV, pyrrolic nitrogen at ~399.6 eV, quaternary nitrogen at ~400.5 eV, and pyridine N-oxide at ~402.1 eV.…”

Carbon Nanostructures Derived through Hypergolic Reaction of Conductive Polymers with Fuming Nitric Acid at Ambient Conditions

“…In respect to the starting polymer, the characteristic diffraction peaks at 20.4° and 25° ( Figure 1 top, red line) corresponding to the (020) and (200) crystal planes of PANI [ 22 , 23 ] are present. These peaks are attributed to π–π interchain stacking, as well as, to the parallel and perpendicular periodicity of the polymer chains [ 24 ]. On the contrary, the XRD pattern of the derived carbon exhibits a very broad reflection centered at d 002 = 3.9 Å ( Figure 1 top, black line).…”

“…The attenuated total reflectance -infrared spectrum (ATR-IR) of the carbon solid compared to that of the starting polyaniline is shown in Figure 2 , top. As far as PANI is concerned, the peaks at 1572 cm −1 and 1494 cm −1 are assigned to the stretching deformation mode of the quinoid and benzenoid rings, respectively [ 24 , 29 ]. The carbonyl group of the acetic acid used for the polymer treatment is clearly distinguished at 1700 cm −1 .…”

“…The bands at 1280 cm –1 and 1226 cm −1 are attributed to C–N and C=N stretching vibrations, the weak shoulder at 1080 cm −1 to aromatic C–H in plane deformation and the weak band at 780 cm −1 to the out of plane bending mode of aromatic C–H groups. The weak shoulder near 3000 cm −1 is assigned to C–H moieties while the peak at 3250 cm −1 is attributed to the stretching vibrations of N–H moieties [ 24 , 29 , 30 , 31 ]. On the other hand, the spectrum of the polyaniline-derived solid is suggestive of oxidized carbon decorated with oxygen-containing functionalities and incorporating nitrogen in its structure ( Figure 2 , top).…”