Simplified Preparation of N-Doped Carbon Nanosheets Using EDTA Route

Amorphous carbon and its heteroatom-doped derivatives often exhibit wrinkled, defective, porous structures, and find wide applications in the fields of energy storage and catalysis. To date, although many methods for preparing doped carbon materials have been reported, the preparation process is relatively complex, and there are still few simple methods available. Therefore, it is necessary to further develop simple and feasible preparation methods. In this study, we employed commercially available manganese disodium ethylenediaminetetraacetate (EDTA-Na₂Mn, serving as both carbon and nitrogen sources) as the precursor. Through thermal decomposition under a nitrogen atmosphere, a nitrogen-doped carbon composite embedded with manganese monoxide (MnO) was initially obtained. Subsequently, hydrochloric acid etching was applied to remove the MnO phases, yielding the final product: nitrogen-doped carbon, denoted as C-N-Mn. Notably, the carbonization and nitrogen-doping processes were simultaneously accomplished during pyrolysis, thereby streamlining the synthesis route for nitrogen-doped carbons. To demonstrate the versatility of this approach, we extended the methodology to two additional metal–organic salts (EDTA-Na₂Zn and EDTA-NaFe), successfully synthesizing nitrogen-doped carbon materials (C-N-Zn and C-M-Fe) in both cases. The phase composition, morphology, microstructure, specific surface area, and pore volume of the products were systematically characterized using X-ray diffraction (XRD), scanning/transmission electron microscopy (SEM/TEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption/desorption analysis. These nitrogen-doped carbons exhibit high specific surface areas and tunable pore volumes, suggesting their potential applicability in energy storage systems.