ИСТИНА

There are a lot of data about promising properties of graphite oxide and its derivatives (for example reduced graphite oxide, graphene). However some problems take place – defects of structure, little pores, and negative sorption activity of certain compounds. Herewith graphite oxide obtained by graphite oxidation is a matter with no regular structure. Structure of graphite oxide depends on synthesis procedure, conditions, type of graphite as reagent. Sorption properties depends on exactly features structure as presence, relative position, ratio of oxygen-containing functional groups, ratio sp2/sp3 C, its size and position. Thus reliable data of structure is needed. One of way to solve this problem can be computer simulation. It allows assuming possible structure fragments. These results will complement experimental data mainly gross composition. In present work graphite oxide synthesized by the Tour method [1] and membrane based on graphite oxide obtained by filtration method [2]. The following data were received: atomic composition of surface (XPS), microphotography (SEM), diffractogram (РФА) and IR-spectra. These data give us to suggest preliminary conclusions about presence of certain oxygen-containing functional groups on surface and their ratio. Correlation of IR-signals and functional groups of graphite oxide is ambiguously because ranges of structural fragments (including the frame) characteristic oscillation are overlapped. Thus calculation data are needed. We realized quantum chemical simulation of systems CnOmHkSlNj (n=24÷54; m=3÷15; k=0÷20; l=0÷2; j=0÷2) consisted of different number of functional groups: -COOH, =O, -OH, -SO3, -NO2. Calculations were carried out in the approximation of DFT with hybrid exchange-correlation functional B3LYP and extended double-exponential Gauss-type basis (DFT-B3LYP/6-31G(d,p)). Analysis of normal oscillation of model graphite oxide units allow us to plot theoretical spectra of oscillation. In results the most possible graphite oxide units (location of functional groups) were suggested by correlation of theoretical and experimental spectra. Also possible ways of graphite oxidation were investigated. Calculation is carried out using the equipment of the shared facilities of HPC computing resources at Lomonosov Moscow State University [3]. Experimental data were received in Scientific Research Shared Centr "Nanochemistry and chemistry of atmosphere".