Doping and functionalization of graphene significantly modulate its properties and extend its application potential. Detailed and accurate chemical characterization of the final material is critical for understanding its properties and reliable design of new graphene derivatives. Spectroscopic methods commonly used for this purpose include Raman, Fourier transform infrared (IR), and X-ray photoelectron spectroscopy (XPS). However, the correct interpretation of observed bands is sometimes hampered by ambiguities when assigning measured binding energies or IR/Raman peaks to specific atomic structures. N-doped graphene has many potential applications but can contain several different chemical forms of nitrogen whose relative abundance strongly affects the doped material's properties. We present clear spectroscopic fingerprints of the various chemical forms of nitrogen that can occur in N-doped/functionalized graphene to facilitate the identification and quantification of the different forms of N present in experimentally prepared samples. The calculated XPS binding energies of the N 1s state for graphitic, pyrrolic, pyridinic, and chemisorbed nitrogen in N-doped graphene are 401.5, 399.7, 397.9, and 396.6 eV, respectively, and hydrogenation of pyridinic N shifts its peak to 400.5 eV.

The nitrogen doping of graphene via mild and low energy processes to afford homogeneous product composition and topology with high nitrogen content (>10 at. %) remains a challenge of contemporary 2D materials chemistry. Here, we report a previously unexplored route to synthesize N-doped graphene (NG) with exceptionally high N content (up to 18.2 at. %) by reaction of fluorographene (FG) with NaNH 2 in N,N-dimethylformamide (at 130°C) or acetonitrile (at 70°C). The N content can be tuned by changing the reaction time, temperature, and/or solvent, ranging from 6.6 to 18.2 at. %, mainly in the form of pyridinic and pyrrolic configurations. With thermal annealing, the N content remained constant up to 400°C but then decreased by ∼50% upon being further annealed to 1000°C. Density functional theory (DFT) calculations showed that nitrogen incorporation into the carbon lattice mostly occurred at vacancies present in the starting material. We also conducted a thorough rationalization of sidereaction pathways leading to byproducts, which were confirmed by GC-MS analysis. This is the highest yet recorded N content for a wet chemical doping procedure and at such a low temperature of 70°C. The reported synthetic approach thus offers a sustainable and cost-effective way to prepare NG with a broad tunability window of N content for potential applications related to energy storage and catalysis.

Graphene derivatives with anchored metal atoms represent a promising class of single‐atom catalysts (SACs). To elucidate factors determining the bond strength between metal atoms and graphene derivatives, a series of late 3d and 4d elements, including the iron triad, light platinum group elements, and coinage metals (Fe, Co, Ni, Ru, Rh, Pd, Cu, Ag, and Au), in different oxidation states (from 0 to +III) bonded to either cyanographene (CG) or graphene acid (GA) is explored. The vast diversity of N···Me and O···Me bond dissociation energies is related to charge transfer between the metal and substrate. The ability of CG and GA to reduce metal cations and oxidize metal atoms is attributed to the π‐conjugated lattice of the graphene derivatives. The binding energies of core electrons of the anchored metals are predicted to enable experimental identification via X‐ray photoelectron spectroscopy. The anchoring of metals is accompanied by either complete or partial spin quenching, leading in most cases to the same oxidation state of the metal regardless of its initial charge. The identified features can be utilized in designing new materials with a high potential in heterogenous SACs as well as electrochemical and spintronic applications.