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As an one of the most promising materials of green energy as a photocatalyst for the production of hydrogen from renewable, natural sources (water, greenhouse gas) and environmental remediation through the degradation of toxic organic pollutants, graphite-like carbon nitride (characterized as a non-toxic and chemically highly resistant material) and its nanostructured and doped (especially by oxygen atoms) derivatives attract special attention. The actual task for expanding the scope of application of g-C 3 N 4 is to improve and optimize its catalytic, electronic and optical properties by increasing both the surface area of graphitic carbon nitride and the number of active centers of the carbon nitride network due to doping of carbon nitride. The use of a mixture of two different precursors ensures the creation of heterojunctions, and as a result, an improvement the photocatalytic characteristics of g-C 3 N 4. The oxygen-doped carbon nitride (O-g-C 3 N 4) and water-soluble carbon nitride oxide (g-C 3 N 4)O was simultaneously synthesized by the gas phase method under special reaction conditions of pyrolysis of cyanuric acid and urea mixture. Reduction by the hydroquinone of carbon nitride oxide (g-C 3 N 4)O yields nanostructured reduced carbon nitride (or reduced multilayer azagraphene). Obtained products were characterized by using Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), chemical and X-ray diffraction (XRD) analyses, scanning electron microscopy (SEM). According to the results of XPS and IR spectrometry the chemical bonds between atoms in a heteroatomic plane of reduced carbon nitride (RCN) correspond to the bonds in a synthesized carbon nitride (SCN). However, according to XRD results, reduced carbon nitride (RCN) probably consists of poorly connected heteroatomic azagraphene layers, because it has a significantly larger (on 0.09 nm) interplanar distance between the adjacent nitrogen-carbon layers than interplanar distance between the layers of synthesized carbon nitride (SCN). By SEM characterization it was found that the pyrolysis of a mixture of various precursors (cyanuric acid and urea) yielded a product with smaller crystalline domains (which can improve photocatalytic characteristics) than the pyrolysis of a single precursor (urea only).

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