Nickel nanocomposites: magnetic and catalytic properties

• Published in: RSC advances 2015-01, Vol.5 (77), p.63073-63079
• Main Authors: Castillo, C., Seguin, K., Aguirre, P., Venegas-Yazigi, D., Viegas, A. D. C., Spodine, E., Paredes-Garcia, V.
• Format: Article
• Language: English
• Subjects: Catalysis; Catalysts; Chitosan; Ferromagnetism; Metal particles; Nanocomposites; Nickel; Polyethylenes
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/C5RA09622G

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 θ values of 44.5°, 51.9°, 76.4° 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 Ni0-NPs on the matrix surfaces is observed. While the spherical shape observed for isolated Ni0-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 Ni0-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.