Copper-containing composites of polyaniline were synthesized by introducing copper(II) chloride (with the reduction of copper cations with sodium borohydride and hydrazine hydrate and without it) in the oxidative polymerization of aniline (ammonium peroxydisulfate oxidant). The resulting polyaniline-copper composites were studied by IR spectroscopy, atomic force microscopy, and X-ray diffraction analysis. The more drastic increase in the rate of hydrogenation of p-nitroaniline and its conversion (compared with those of the electrochemical process on the Cu cathode) resulted from the activation of the cathode with polyaniline composites with the copper salt, whose cations were reduced to the metal phases in the electrochemical system.

Bimetallic Ni/Cu core–shell and Cu-Ni heterostructural micro- and nanoparticles were prepared using two simple successive reduction procedures. Monometallic Ni and Cu particles were synthesized for comparison. The phase constitutions and morphological features of the particles were studied by means of X-ray diffraction, energy-dispersive X-ray spectroscopy, and scanning electron microscopy methods. All the prepared mono- and bimetallic particles were applied as electrocatalysts in the electrohydrogenation of p-nitrophenol (p-NPh). An additional electrochemical reduction of copper cations during the hydrogen saturation of Cu-containing particles was established. The prepared Ni/Cu particles exhibited the highest electrocatalytic activity with an increase in the hydrogenation rate of p-NPh by more than three times compared to its electrochemical reduction on the nonactivated cathode, and p-NPh conversion yielded the maximum values. The main product of p-NPh electrocatalytic hydrogenation over Ni-Cu particles is p-aminophenol, which is an intermediate in the synthesis of many drugs. p-Aminophenol formation is confirmed by UV-Vis spectra.

Polymer-silver composites are prepared by in situ introducing silver(I) nitrate to the oxidative polymerization of aniline and polycondensation of aniline or melamine with formaldehyde. The data of...

The preparation of copper-carbon composites using functionalized multi-walled carbon nanotubes (MWCNTs), fullerene black (FB) and N-containing soot prepared by carbonization of aniline-formaldehyde polymer (AFS) is described. The composite structure was studied by X-ray diffraction analysis, Electron spectroscopy and Energy-dispersive spectroscopy microanalysis. The influence of the nature of the carbon materials on the formation of copper micro- and nanoparticles prepared by a chemical reduction in their presence has been established. The resulting copper-carbon composites were used as electrocatalysts in the electrohydrogenation of nitrobenzene. The MWCNTs and AFS composites with a ratio to copper of 1 : 1, as well as composites with a mixed carbon base, showed electrocatalytic activity with an increase in the rate of hydrogenation of nitrobenzene compared to its electrochemical reduction on a non-activated copper cathode. It is assumed that due to the strong interaction of copper particles with the FB, its electrocatalytic activity was depressed. The nitrobenzene hydrogenation on all composites is accompanied by the formation of the main product aniline, as would be expected when the process is carried out in an alkaline environment and high voltages in the system. According to chromatographic analyses, the aniline yields were 98-99%.

N-doped graphene is not only a promising metal-free catalyst, but also a convenient carrier of metal nanoparticles for the creation of effective catalysts. Graphitic carbon nitride (g-C3N4) is used more often in photocatalytic processes and less often as electrocatalysts. This paper describes the preparation of N‑containing carbon composites consisting of reduced graphene oxide (rGO) and g-C3N4 for the further creation of metal-carbon catalytic systems. These composites were prepared by the heat treating dry mixtures of graphene oxide (GO) and melamine (MA) in the temperature range of 450-550 °C in air. Oxygen-containing groups were identified in the graphene oxide samples synthesized by the modified Hummers method and in its reduced form. The thermogravimetric analysis method was used to determine the ranges of relative thermal stability of the GO + MA mixtures, which were found to be almost identical for the studied compositions with different component ratios. The structure of the graphene oxide and its composites with MA after heat treatment was studied by scanning electron spectroscopy, X-ray diffraction analysis, FTIR spectroscopy and elemental analysis. The effect of the ratio of the initial components on the formation of the heat treatment products was determined. It was shown that to obtain the rGO+g-C3N4 composites with a high content of carbon nitride, the ratio of the initial reagents should be taken equal to 1:2, and the heat treatment should be carried out at 550 °C.