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In the frame of the preparation of carbonaceous materials that could serve for instance as anodic components in lithium batteries, an original way has been proposed based on the electroreduction of carbonate ions in ternary molten Li-Na-K carbonates. The TEM and XRD analyses show that the powders produced at the cathode are made of carbon nanoparticles composed of both amorphous and graphitized domains. The characteristic properties of the product depend on the operating conditions: voltage, melt temperature and annealing temperature. BET investigations show that the active surface area of the powders obtained at high voltage (6 V) and low melt temperature (450 • C) grows to a value of up to 1300 m 2 g −1 . An improvement of the anodic material in lithium batteries can be obtained by introducing in the carbon powder suitable metals such as tin. The production of such mixtures can be realized directly, in one single operation, by electroreduction of metal ions dissolved in the alkali carbonate melt. The mechanism of metal deposition is briefly studied by cyclic voltammetry. Composite powders are electrodeposited at constant potential. TEM and EDX investigations show that they are made of an intimate mixture of carbon and metal grains at the nanometric scale, the metallic grains size ranging from 5 to 20 nm.In the field of rechargeable lithium batteries much effort has been devoted to the development of efficient negative electrodes. 1,2 Indeed, from a theoretical point of view, the best device would be to use lithium metal as an anode material; however, lithium is highly active and reacts with most electrolytes. Further, the morphology of lithium deposits is dendritic, inducing a non-dimensionally stable electrode. In modern cells these disadvantages were alleviated by using lithium alloys or by inserting lithium atoms in a host material. Of course, it results in a decrease of specific energy and the inconvenience can be accepted if the use of such anode materials significantly improves cycle life and safety. The additional compounds are generally made of carbon or metals such as tin or silicon.The performances of carbon materials strongly depend on the carbon structure which varies from the highly crystalline graphite to strongly disordered carbon. [3][4][5][6][7][8][9] The layered structure of graphite is particularly well adapted to the insertion of lithium which occurs between the graphite sheets. Some advantage has also been found by using hard carbon which develops high capacity at low potential and inserts lithium over a large potential range. The gradual potential change is an advantage for practical uses since it permits a more accurate estimate of the remaining capacity. Different techniques were used to produce such carbonaceous materials notably from electrochemical route by electro-oxidation, or from electro-reduction of molten salts. 10-17 In our laboratory, the generation of carbon powders was carried out by electro-reduction of alkali carbonate melts. 18-24 Quasi-spherical carbon nano-particles wer...

The CO2 methanation was studied over 7 wt.% nickel supported on Ce0.2Zr0.8O2/AC to evaluate the correlation of the structural properties with catalytic performance. The catalysts were investigated in more detail by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). A sample of 7 wt.% nickel loading supported on activated carbon (AC) was also prepared for comparison. The results demonstrated that the ceria-zirconia solid solution phase could disperse and stabilize the nickel species more effectively and resulted in stronger interaction with nickel than the parent activated carbon phase. Therefore, 7% Ni/Ce0.2Zr0.8O2/AC catalyst exhibited higher activity for CO2 reduction than 7% Ni//AC. It can attain 85% CO2 conversion at 350°C and have a CH4 selectivity of 100% at a pressure as low as 1 atm. The high activity of prepared catalysts is attributed to the good interaction between Ni and Ce0.2Zr0.8O2 and the high CO2 adsorption capacity of the activated carbon as well.

An atomic implantation method was used to modify diatomite with CuCl. The CuCl/diatomite samples were characterized by different techniques, including FTIR, XRD, BET, SEM-TEM, EDX, and CO-TPR. Characterization results revealed the formation of CuCl particles of 50–60 nm highly dispersed on diatomite surface. CO adsorption measurements showed that 2CuCl/diatomite exhibits the highest CO adsorption capacity among all CuCl-modified samples with diatomite. Its CO adsorption capacity of 2.96 mmol/g at 30°C is 10 times higher than that of unmodified diatomite (0.29 mmol/g). The CO adsorption on CuCl-modified diatomites was found to fit well with the Langmuir–Freundlich model.

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