SYNTHESIS AND CHARACTERIZATION OF BIMETALLIC NI-CU COLLOIDS

The goal of the present study was the investigation of bimetallic coll oidal systems to be used as precursors of bifunctional catalysts dispe rsed on a support and as a precursor of bimetallic films. Bimetallic c olloids of Ni-Cu were prepared by vaporization of an alloy and coconde nsation with organic solvents at 77 K. Active powder for catalytic pur poses were obtained by solvent evaporation. The chemical liquid deposi tion (CLD) method was used to prepare films. The colloids was characte rized by several studies, including the stability at room temperature without additives, particle size growth, UV-visible (UV-vis) and Fouri er transform infrared (FT-IR) spectroscopy, transmission electron micr oscopy (TEM) with energy dispersive X-ray (EDAX), and thermogravimetri c analysis (TGA). The solvents under study were 2-methoxyethanol, 2-pr opanol, and acetone. These studies confirmed that Ni-Cu bimetallic col loids with 2-methoxyethanol were stable for months, while acetone and 2-propanol did not produce stable colloids. The studies of the (Ni-Cu) -2-methoxyethanol colloids by W-vis demonstrated that colloids with bi metallic particle were formed. The particle size growth was of the fil m prepared by evaporation of 2-methoxyethanol showed the incorporation of the solvent, which enables colloid stabilization by bonding either to Ni or Cu through the oxygens. The EDAX studies showed the presence of metallic Ni anc Cu in the films. The thermal studies of the films showed a weight loss of 31.6% between 120 and 550 degrees C. (C) 1998 Elsevier Science Ltd.