Аңдатпа
Thermal and electrochemical reduction of nickel (II) ferrite under the influence of polymer stabilizersNickel (II) ferrite samples have been prepared by co-precipitation of metal salts in an aqueous solution without and with the addition of polymer stabilizers (polyvinyl alcohol and polyvinylpyrrolidone) and further heat treatment at 500 °С, 700 °С and 900 °С.Their structural-phase changes before and after using as catalysts in the electrohydrogenation of acetophenone were revealed by X-ray phase analysis.Morphological features of the obtained NiFe2O4 and NiFe2O4 + polymer samples were studied by electron microscopy.It has been established that the addition of polymer stabilizer into the co-precipitation medium and its partial preservation in the composition of precursors (metal hydroxides and oxides) and in the formed nickel (II) ferrite have a noticeable effect on the structural-phase constitutions of the samples prepared.Differences in the phase constitutions are also depend on the heat treatment temperature of these samples.It was shown that, in contrast to nickel ferrite synthesized without stabilizers, NiFe2O4 + polymer samples are partially reduced during heat treatment and additionally in an electrochemical system with the formation of Ni-and Fe-Ni-containing composites.The reduced samples of nickel (II) ferrite were tested for their ability to exhibit electrocatalytic properties in the electrohydrogenation of acetophenone.Their low electrocatalytic activity in this process was determined, which is presumably conditioned by the structure of Fe-Ni-alloy particles with iron content predominant, as well as by the presence of magnetite inhibited the activity of nickel particles.