Synthesis and properties of Au–Pd bimetallic colloids

Gold–palladium bimetallic colloids were obtained by chemical liquid deposition (CLD). Two concentrations (low, high) of the metals were used. The metals were melted and then evaporated to yield alloy atoms, which were solvated to yield a matrix at 77 K. Upon warming of the matrix, stable liquid colloids were formed. The solvents used were acetone, 2-butanone, THF, DMF, 2-ethoxyethanol, and 2-propanol. A study of particle size at room temperature performed by transmission electron microscopy (TEM) revealed that for the low concentration of metals the smallest mean particle sizes obtained were, respectively, 36.5, 37.7, 33.2, 27.5, 51.6, and 25.1 Å. Particle size was found to be dependent on the solvent used. Zeta potentials were calculated for these negatively charged particles, using the Hunter convention and the Debye–Hückel equation. The films obtained after solvent evaporation were studied by thermogravimetry to determine their thermal stability.