Refinement of the Microwave-Assisted Polyol Process for the Low-Temperature Synthesis of Intermetallic Nanoparticles

The microwave-assisted polyol process was applied to synthesize phase-pure micro- or nanocrystalline intermetallic phases in the systems T-M (T = Co, Ni, Rh, Pd, Ir, Pt and M = Sn, Sb, Pb, Bi). Reaction temperatures range between 240 and 300 degrees C, and reaction times of a few minutes up to 1 h are sufficient. For optimization of the syntheses, the reaction temperature, reaction time, and metal precursors were changed. To obtain phase-pure samples the process was further modified by the addition of potassium hydroxide, oleylamine, or oleic acid. Single-phase powders of a variety of intermetallic compounds were synthesized. Although not stable at the temperature of synthesis, high-temperature phases are accessible as well. The microwave-assisted polyol process opens up the possibility to synthesize intermetallic compounds through a fast and easily applicable one-step route, without utilization of strong and often toxic reducing agents.