The aim of the current study was to find changes in the structure and state of the surface of graphene oxide (GO) under the conditions of its reduction and modification by hetero atoms of nitrogen and amino acids. Reduction of GO was performed with hydrazine hydrate (R-GO), doping with nitrogen atoms - urea impregnation and subsequent heat treatment (N-GO), and the surface of GO was modified with sulfur-containing amino acid – L-cysteine by nucleophilic addition (L-GO). The samples obtained were characterized by analytical methods, such as Raman scattering, IR spectroscopy, TPD-mass-spectrometry, dynamic light scattering spectroscopy. The available Raman spectra indicate a defective structure of GO, reduction of GO leads to greater ordering of the structure in relation to GO, nitrating and modification by amino acid - to the opposite effect, a slight deterioration of the structural state. According to the results of IR spectroscopy, also confirmed by TPD-MS, GO has a large number of functional surface groups: (OH), (C=O), (C=C), (C-O-C), (CO-O-CO), (CH). Hydrazine reduction completely hydrophobizes the surface, in the IR spectra there is only a peak at ~ 1040 cm–1, which corresponds to CO-O-CO vibrations, with significantly reduced intensity, as well as bands at 2120 and 2300 cm–1, which indicate the aromatic nature of the samples and exist in all GO derivatives. In nitrogen and sulfur-containing samples (L-GO) a new peak of ~ 1520 cm–1appears, which corresponds to N-H vibrations in amines. Sulfur-containing derivatives have valence vibrations at 600 cm–1, which most likely corresponds to S-H bonds. Thus, modification of GO leads to a significant change in its structure and surface chemistry, which in turn affects the capability of the obtained samples to capture free radicals. Previous empirical studies have shown that this property increases in the series L-GO > GO > N-GO > R-GO.

Nitrogen-containing carbon nanotubes (CNTs) were synthesized by the CVD method on oxide catalysts of Al-Fe-Mo-O by adding acetonitrile or ethylenediamine to the carbon source (propylene), or completely replacing it, as well as impregnating the original CNTs with urea, followed by heat treatment. The structure of nitrogen-containing CNTs (N-CNT) was characterized by the method of Raman scattering, transmission electron microscopy (TEM), differential thermal and gravimetric analysis (DTA, DTG) and X-ray photoelectron spectroscopy (XPS). The influence of the synthesis method on the number and chemical state of nitrogen heteroatoms in the structure of the carbon matrix is found. According to the TEM, nitrogen-containing CNTs have a characteristic bamboo-like structure, which is less perfect compared to the structure of the original CNTs: the characteristic Raman bands (G and D) are shifted to higher frequencies, their half-width and band D intensity increase relative to G. This is also manifested in the lower thermal stability of nitrogen-containing CNTs. According to the XPS, the direct synthesis of nitrogen-containing CNTs increases the total content of nitrogen atoms and the proportion of pyrrolic and quaternary nitrogen against the background of a significant decrease in the amount of pyridinic form. This can be explained by the fact that nitrogen is evenly distributed throughout the carbon matrix of CNTs, and during nitriding of CNTs with urea, nitrogen is included mainly in the surface layers and defects, because the pyridine form is characteristic of the edge location of the nitrogen atom in the graphene plane.The catalytic effect of multilayer nitrogen-containing carbon nanotubes (N-CNT) on the kinetics of decomposition of hydrogen peroxide in aqueous solutions at different pH values is considered. It is concluded that the method of direct synthesis of nitrogen-containing CNTs allows to obtain more catalytically active carbon nanotubes containing more nitrogen, mainly pyrrolic and quaternary type. It has been found that regardless of the method of synthesis, the maximum catalytic activity in the decomposition of hydrogen peroxide is observed at pH 7.

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