Bromination of carbon nanohorns to improve sodium ion storage performance

Carbon nanohorns CNHs have low layering, internal cavities, a large number of defects and these structural features are important for the effective accumulation of sodium ions. Since nanohorns can be easily modified, this opens up possibilities for controlling their properties. In this work, initial CNHs and CNHs opened by thermal oxidation in the air were successfully brominated to bromine concentrations of 7 and 5 at , respectively. Cyclic voltammetry curves revealed two peaks at potentials of 1.4 and 2.1 V vs Na Na and the related processes contributed to the capacity of the brominated samples. Density functional theory calculations showed that the peaks correspond to reversible adsorption desorption of Na ions on the surface of CNHs near the brominated tips and the adsorbed bromine molecules. As a result, brominated open CNHs with a large amount of Br2 had the highest specific capacity of 129 62 mAh g amp; 8722;1 at 0.1 2 A g amp; 8722;1 as compared to the corresponding values of 117 41 mAh g amp; 8722;1 for the initial CNHs. Our results show that the bromination of carbon materials, pretreated for controlling the introduction of certain forms of bromine, is a way to improve their performance in sodium ion batterie

Redox reactions between acetonitrile and nitrogen dioxide in the interlayer space of fluorinated graphite matrices

The interlayer space of 2D materials can be a slit reactor where transformations not typical for the gas phase occur. We report redox reactions involving acetonitrile and nitrogen oxide guests in galleries of fluorinated graphite. Fluorinated graphite intercalation compounds with acetonitrile are treated with dinitrogen tetraoxide and the synthesis products are studied by a set of experimental methods. Data analysis reveals that N2O4 dissociates in fluorinated graphite matrices to form nitrogen containing species NO3, NO2, NO, and N2. The interaction of NO3 with acetonitrile yields HNO3, which predominates as a guest in the synthesis products independently of the fluorination degree of the matrix. This reaction is accompanied by the removal of fluorine atoms weakly bonded to the graphite layers, leading to partial defluorination of the matrices. Our work demonstrates the possibility of using fluorinated graphite as a test nanoreactor whose dimension can be controlled by fluorination of the layers

Water purification from chlorobenzenes using heteroatom functionalized carbon nanofibers produced on self organizing Ni Pd catalyst

The development of effective methods for the processing of hazardous wastes containing chlorinated hydrocarbons still remains a big challenge. Herein, the approach allowing the transformation of chlorohydrocarbons into functionalized carbon nanomaterials was demonstrated for 1,2 dichloroethane DCE used as a model compound. Carbon nanofibers CNF doped with nitrogen and oxygen heteroatoms were fabricated by a joint decomposition of DCE and co reagent CH3CN, NH4OH, C2H5OH, and H2O . The Ni Pd 5 alloy was used as a catalyst precursor for the CNF synthesis. Pristine Ni Pd alloy was found to undergo disintegration under the reaction conditions and to induce an active growth of the functionalized carbon nanofibers. The obtained CNF were shown to have a similar segmental structure of carbon filaments and to possess high specific surface area up to 470 m2 g and porosity up to 0.9 cm3 g . According to X ray photoelectron spectroscopy data, the nitrogen content within CNF samples prepared using N comprising precursors was about 1.0 1.7 at . The total oxygen content reaches 3.6 at . The obtained materials were demonstrated to be attractive for the dichlorobenzene adsorption from its aqueous solution