| dc.description.abstract | In this study, we are reporting the synthesis and characterization of nanocomposites obtained
from the direct reduction of nickel(II) salts on matrices of polyethylene (Pe) and chitosan (Ch) in
the presence of serine under solvothermal conditions. Using different molar ratios between the
metal salt (M) and the amino acid (AA), eight nanocomposites were prepared, Ni-Pe1; Ni-Pe2;
Ni-Pe3; Ni-Pe4 and Ni-Ch1; Ni-Ch2; Ni-Ch3; Ni-Ch4 (M : AA = 1 : 1, (1); 0.5 : 1, (2); 0.25 : 1, (3)
and 0.125 : 1, (4)). The synthesized composites were characterized by X-ray powder diffraction
techniques; in all the cases, the peaks associated to the matrix (Pe or Ch) and three peaks at 2
theta values of 44.5 degrees, 51.9 degrees, 76.4 degrees were identified, which correspond to
the Miller indices (111), (200), (220). These indices are characteristic of a face centred cubic Ni-
0 phase. The SEM images of the composites show that the use of an organic matrix changes
the size and distribution of the metallic particles because in all the cases a homogenous
dispersion of Ni-0-NPs on the matrix surfaces is observed. While the spherical shape observed
for isolated Ni-0-NPs is retained on the matrices, the size of the metallic particles is smaller than
100 nm with less size variability, as compared with the isolated Ni-0-NPs. All the composites
have a weak ferromagnetic behaviour with similar hysteresis loops, presenting H-c values
ranging from 120 to 226 Oe and reaching saturation at approximately 3 kOe. Preliminary
catalytic properties for hydrogen transfer reaction were also investigated, showing that the
composites exhibit an important activity in the transformation of acetophenone to 1-
phenylethanol. | |
