Purification of Pt-loaded carbon nanoparticles by dielectrophoresis

Abstract

It is generally difficult to selectively capture specific nanoparticles from particle mixtures by conventional separation methods, for example, sedimentation and filtration. In the present study, carbon nanoparticles having an average diameter of 27 nm loaded with Pt nanoparticles having an average diameter of 1.9 nm were separated from their mixture with pristine carbon nanoparticles. For the particle-separation experiments, the Pt-loaded carbon nanoparticle (Pt-CNP) was prepared from commercial carbon black by loading Pt from a H2PtCl6 aqueous solution. The electrodes used for di-electropheresis (DEP) separation were fabricated by photolithography, and the target particle mixture was dispersed in ethanol. It was found that the Pt-CNP was purified by the present DEP separation. The influences of the electrode motion speed, the amplitude and the frequency of AC voltage applied on the electrodes, the duration to apply voltage in liquid, and the addition of a surfactant were investigated. It was found that there were optimized values in these operation parameters to achieve a high purification factor reaching approximately 92%, and the reasons of these influences were qualitatively discussed. © 2014 The Society of Chemical Engineers, Japan.