Elemental superdoping of graphene and carbon nanotubes

Abstract

Doping of low-dimensional graphitic materials, including graphene, graphene quantum dots and single-wall carbon nanotubes with nitrogen, sulfur or boron can significantly change their properties. We report that simple fluorination followed by annealing in a dopant source can superdope low-dimensional graphitic materials with a high level of N, S or B. The superdoping results in the following doping levels: (i) for graphene, 29.82, 17.55 and 10.79 at% for N-, S- and B-doping, respectively; (ii) for graphene quantum dots, 36.38 at% for N-doping; and (iii) for single-wall carbon nanotubes, 7.79 and 10.66 at% for N- and S-doping, respectively. As an example, the N-superdoping of graphene can greatly increase the capacitive energy storage, increase the efficiency of the oxygen reduction reaction and induce ferromagnetism. Furthermore, by changing the degree of fluorination, the doping level can be tuned over a wide range, which is important for optimizing the performance of doped low-dimensional graphitic materials.

Highly Doped Carbon Nanobelts with Ultrahigh Nitrogen Content as High‐Performance Supercapacitor Materials

“…Quantitative elemental analysis reveals that the surface elemental contents of each sample are similar to its corresponding bulk composition derived from EA (see Table ). Remarkably, to our knowledge, the surface N contents in the N–CNB7 and N–CNB8 are higher than most of yet reported values from N–doped carbon nanostructures, with only one exception of N–doped graphene published recently . In particular, their N doping levels are much higher than those of the previously reported N–doped carbon nanostructures prepared using bulk PPy precursors.…”

Tailoring Highly N‐Doped Carbon Materials from Hexamine‐Based MOFs: Superior Performance and New Insight into the Roles of N Configurations in Na‐Ion Storage

“…Compared to N‐doped carbons derived from other N‐containing precursors such as polyaniline, polypyrrole, polyacrylonitrile or those obtained from post‐treatment of carbons with NH 3 , the HNCs obviously exhibit a significantly higher doping level. Several other highly N‐doped carbons have been successfully synthesized, but they often require expensive, sophisticated equipment or harsh conditions . Therefore, the HMT‐based MOFs construction strategy is very efficient for the scalable preparation of HNCs.…”

“…In this case, the three samples whose N‐6/N‐Q ratios were in the range ≈2.0–5.0 (Table S3, Supporting Information), i.e., HNC‐800, HNC‐700–5, and HNC‐800–5, exhibited both higher specific capacities and better cyclic stabilities. Note that this rule for the N‐6/N‐Q ratio only applies to N‐doped carbons that are prepared from in situ pyrolysis of organic precursors and not to N‐doped carbons prepared from a post‐treatment process, such as N‐doped carbon nanotubes or graphene obtained from NH 3 treatment, due to the absence of a clear relationship between the carbon texture and N dopants, and no clear conversion rule among the various N configurations.…”

Excellent Compatibility of the Gravimetric and Areal Capacitances of an Electric‐Double‐Layer Capacitor Configured with S‐Doped Activated Carbon

“…The first two dominant peaks were assigned to the S 2p 3/2 and S 2p 1/2 peaks of aromatic sulfide groups (−C−S−C−), and the last peak corresponded to oxidized S (such as sulfone groups) . As shown in Figure c, the N 1s peak could be deconvoluted into two peaks at binding energies of 398.5 and 400.9 eV, corresponding to the pyridinic and pyrrolic N atoms, respectively . The C 1s spectrum was fitted with six peaks with binding energies of 284.8, 285.6, 286.2, 287.7, 289.9, and 290.9 eV, which were assigned to C=C, C−C, C−S, C−N, O−C=O, and π–π interactions, respectively (Figure d) …”