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Silicon nano- and microparticles obtained using electric-spark dispersion of silicon electrodes and granules in 40 wt% solution of methyl alcohol in water were investigated by ultrasoft X-ray emission spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, scanning and transmission electron microscopies. In addition, the SiLα spectra of obtained silicon particles were modeled by superimposing the spectra of pure silicon and silicon oxide taken in certain weight ratios. It was found that the surfaces of Si nano- and microparticles obtained in 40 wt% solution of methyl alcohol in water are covered with silicon oxide and chemisorbents, while the core consists of crystalline silicon with a cubic face-centered lattice. The silicon nano- and microparticles show potential as an anode material to replace commonly used graphite electrodes. The charge capacity of the electrode based on mixture of Si nano- and microparticles with graphite powder was about 1272 mAh/g after ten cycles. [ABSTRACT FROM AUTHOR]

Hollow graphitic carbon nanoparticles (HGCNs) obtained by catalytic graphitization of acetylene carbon black (ACB) were investigated using ultra-soft X-ray emission spectroscopy. The electronic structures of the ACB HGCNs were compared with those of HGCNs obtained from iron carbide-filled carbon nanocapsules (Fe3C@CNCs) and Q-graphenes. The occupation of the π sub-band decreased in the following sequence: Fe3C@CNC HGCNs > ACB HGCNs > Q-graphenes. This sequence can be explained by changes in the occupations of the C2p states due to the formation of bonds between carbon and residual metal atoms within the HGCNs. It was also found that the contribution of the overlapping ofppπ+ppσ-states in the ACB HGCN walls toward the spectra of the HGNCs was greater in comparison with the reference Q-graphenes. It was established that ACB was not fully transformed into the HGCNs. Scanning and transmission electron microscopy methods were used to study the spatial structures and morphologies of the fabricated HGCNs. [ABSTRACT FROM PUBLISHER]

Hollow graphitic carbon nanospheres (HGCNSs) obtained by treatment of iron carbide-filled carbon nanocapsules were investigated using the ultra-soft X-ray emission spectroscopy method. Carbon nanocapsules were synthesized by the plasma discharge method in an ultrasonic cavitation field of liquid hexane. It was revealed that additional mixed π + σ -overlapping occurred in the hollow graphitic carbon nanospheres as a result of the bending of the graphene sheets. Some iron atoms remained after washing in acid. It was found that in the hollow graphitic carbon nanospheres, sp- hybrid bonds formed between the carbon and residual iron atoms when high-energy 3 d + 4 s -states overlapped with sp n -hybrid orbitals (2 < n < 3). Scanning and transmission electron microscopy methods were used to study the spatial morphology and structure of the fabricated HGCNSs. The electronic structures of the HGCNSs were compared with those of reference synthetic graphite powder, carbon onions, and graphene nanosheets. [ABSTRACT FROM AUTHOR]