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Ceria-iron oxide mesoporous materials with Fe:Ce molar ratio of 5:5 and 9:1 were synthesized by hydrothermal method using CTAB as a template and subsequently modified with NiO (molar ratio Ni:Fe = 1:2) by incipient wetness impregnation technique. In order to increase the electro-capacitive properties and reduce the intrinsic impedance of the metal oxides, the samples were consecutively modified by reduction in hydrogen to obtain highly dispersed Ni–Fe alloys into ceria matrix. By exploiting the high permeability of carbon inside ferrous alloys, the metal phase has been further modified into ferrous carbides and metal alloys encapsulated within carbon nanofibers. For this purpose, a reaction, already widely studied for the production of hydrogen, was used, that is the decomposition of methanol vapors. In fact, this decomposition, in addition to producing syn-gas and methane, changes the catalysts in use through a chemical vapor deposition-carbon coating process. This fact, has been used by us to demonstrate how the newly obtained metal-carbon nanocomposites can be used for electro-catalytic purposes. The modified phases of the two molar ratios of the Fe–Ni–Ce catalysts were tested in the Oxygen Evolution Reaction (OER) in an alkaline environment (1 M KOH), showing a satisfactory and progressive increase in activity and a surprising decrease in the overpotential at 10 mA/cm2 of current density. The morphological, textural and physicochemical properties of the samples were characterized in details by XRD, N2-physisorption, TG-TPO, TEM, EDX, FTIR, XPS, Raman and Moessbauer spectroscopies.

[EN] The steam activation of carbon foams obtained after thermo-oxidation treatment of coal tar pitch using inorganic acids (H2SO4 and HNO3), and subsequent low pressure foaming process without stabilization step, was investigated. The characterization of the activated carbon foams showed a strong dependence of the final structure of these materials from the chemical composition of the pitch precursor. This was related to the conditions of thermo-oxidation pre-treatment with inorganic acids, used to modify the composition of the initial pitch. In both cases carbon foams with uniform open cell structures were obtained, although they showed very different properties. When nitric acid was used in the initial thermo-oxidative treatment, the steam activation process of the carbon foam proceeded to a larger extent; the porosity parameters of this sample are twice higher than those obtained when using sulfuric acid. This was attributed to the catalytic effect of H2SO4 during the foaming step, which leads to the formation of dense carbon foams with highly ordered structure as inferred from XRD. At converse, densification of the carbon foam did not occur when using nitric acid in the initial thermo-oxidative treatment; the resulting material displayed labile surface groups decomposing at moderate temperatures, as well as an incipient microporosity, which further increased during the steam activation.

[EN] Adsorption of m-aminophenol and p-nitrophenol from aqueous solution on activated carbon synthesized on the base of industrial by product (coal tar pitch) and furfural was investigated. The adsorption capacity of the activated carbon and its oxidized modification is related to the surface area and composition of the prepared materials, as well as to the nature of the adsorbents. Despite the moderate porosity, the prepared materials display adequate adsorption capacity towards the investigated aromatic compounds. Both adsorbates show higher affinity towards the hydrophobic carbon, confirming that the retention mechanism occurs via non-specific interactions between the electronic density of the adsorbent and the aromatic pollutants. Electrostatic interactions may also appear depending on the solution pH and the charge distribution of the carbons; we have established that this parameter has a strong influence on the final performance of the oxidized carbon, where repulsive interactions that reduced the uptake of the carbon were found to appear within a larger pH range.