Synthesis and Characterization of High-Purity Ultrafine Platinum Particles by Chemical Refining Method

Abstract

High-purity ultrafine platinum particles are widely used to fabricate platinum electrode oxygen sensors for automobiles and thick-film platinum resistance temperature elements. In this study, the near-spherical ultrafine Pt particles of high purity were synthesized by chemical purification, spray-drying, and ignition from crude Pt powder. Impurities in the initial Pt powder were eliminated by the 001×7 strong acid cation resin exchange column and precipitation treatment. Near-spherical (NH4)2PtCl6 particles were obtained after spray-drying, and then the microstructure and size of as-synthesized Pt particles were controlled by the ignition process. The influences of different heating temperatures during ignition treatment on the microstructure and size of Pt particles were investigated. The purity of as-synthesized Pt particles was higher than 99.999 wt%, and the average size was about 1.12 μm. The results indicate that high-purity ultrafine Pt particles can be efficiently synthesized by chemical refining.