Effect of Nitrogen Doping on the Structure and Dye Adsorption Properties of Graphene Oxide

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In this study, nitrogen (N)‐doped graphene oxide (GO) is synthesized using the improved Hummers method. The structural characterizations of the samples are monitored by X‐ray diffraction, X‐ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and Raman analyses. Morphological, chemical and optical properties are examined by scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, and UV–vis analyses, respectively. Adsorption properties are evaluated with a dye adsorption test by removing methylene blue (MB) from an aqueous solution. According to the results, the characteristic phase of the GO structure is preserved after doping, and no distinct different phase appeared. It is detected that the amount of hydroxyl and carbonyl groups decreases in N‐GO samples, so it also expands the interlayer distance of GO. In XPS analysis, it is observed that the type of N binding to the GO structure changes depending on the ammonia concentration. In Raman analysis, it is determined that the defect ratio of the graphene basal plane changed according to the ammonia ratio. In the dye adsorption investigation, the N‐doped GO sample, characterized by a larger concentration of pyrrolic bonds, eliminates 97.71% of MB molecules from the solution within 30 min, exhibiting an almost fivefold greater dye adsorption rate constant compared to GO.