Search Results (3)

The aluminum electrolysis industry faces significant challenges due to the high consumption and environmental impact of carbon anodes, which are prone to oxidation in high-temperature and strongly oxidizing environments. This study innovatively introduces aluminum fluoride (AlF₃) as an additive to enhance the oxidation resistance of carbon anodes for aluminum electrolysis. By systematically exploring microstructural evolution through SEM, XRD, Raman spectroscopy, and permeability analyses, it reveals that AlF₃ inserts fluorine atoms into carbon interlayers, forming F-C bonds that reduce interlayer spacing while promoting graphitization. Simultaneously, AlF₃-derived α-Al₂O₃ particles densify the anode and make it more compact, reaching the optimum when 7 wt.% AlF₃ is doped. The bulk density of the carbon anode increased to 2.08 g/cm³, porosity decreased to 0.315, and air permeability reached a minimum of 2.3 nPm. In addition, the fluorine intercalation reduces the electrical resistance to 2.12 Ω via conductive F-C clusters. The demonstrated efficacy of AlF₃ additives in enhancing the oxidation resistance and conductivity of carbon anodes suggests strong potential for industrial adoption, particularly in optimizing anode composition to reduce energy consumption. Full article

The use of neutron reflectors is an effective method for improving the quality of neutron sources and neutron delivery systems. In this work, we further develop the method based on the Bragg scattering of neutrons in crystals with large interplanar distances. We compare samples of differently prepared fluorine intercalated graphites by measuring the total cross section for the interaction of neutrons with the samples, depending on the neutron wavelength. The Brag scattering cross section is expected to be the dominant part of the total cross section in all the cases. The results show that all samples provide high reflection efficiency over the entire range of the so-called “neutron reflectivity gap” and beyond it, and that they also allow for the choosing of the optimal intercalation methods. Full article

Fluorinated graphitic layers with good mechanical and chemical stability, polar C–F bonds, and tunable bandgap are attractive for a variety of applications. In this work, we investigated the photolysis of fluorinated graphites with interlayer embedded acetonitrile, which is the simplest representative of the acetonitrile-containing photosensitizing family. The samples were continuously illuminated in situ with high-brightness non-monochromatized synchrotron radiation. Changes in the compositions of the samples were monitored using X-ray photoelectron spectroscopy and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. The NEXAFS N K-edge spectra showed that acetonitrile dissociates to form HCN and N₂ molecules after exposure to the white beam for 2 s, and the latter molecules completely disappear after exposure for 200 s. The original composition of fluorinated matrices CF_0.3 and CF_0.5 is changed to CF_0.10 and GF_0.17, respectively. The highly fluorinated layers lose fluorine atoms together with carbon neighbors, creating atomic vacancies. The edges of vacancies are terminated with the nitrogen atoms and form pyridinic and pyrrolic units. Our in situ studies show that the photolysis products of acetonitrile depend on the photon irradiation duration and composition of the initial CF_x matrix. The obtained results evaluate the radiation damage of the acetonitrile-intercalated fluorinated graphites and the opportunities to synthesize nitrogen-doped graphene materials. Full article