Improvement on electrochemical performance by partial replacement of Ru@Pt core-shell nanocatalyst by temperature modification

Abstract

In this paper, the homemade open-loop reduction system (OLRS), and redox transmetalation method were utilized to produce the core-shell Ru (ruthenium)/Pt (platinum) catalysts on the carbon cloth (CC) for direct methanol fuel cell (DMFC) application. By adjusting pH value and heating to proper temperature of the ionized reduction environment, Pt4+ can be first converted into Pt2+ to allow partial Ru replacement with Pt by redox transmetalation and produce Ru@Pt core-shell nanostructures[1]. And we change the reduction temperature to see how it affects the efficiency of the DMFC.The scanning electron microscopic (SEM) top-view micrographs showing that the apparent Ru@Pt nanoparticles successfully deposited on both the inner and outer surfaces of the hydrophilically-treated CC. At high SEM magnification, the small size and high-density distribution of the Ru@Pt nanoparticles were clearly observed on the hydrophilically-treated CC, and much more Pt@Ru catalyst deposit on the CC surface with the sample of 80 °C. The electrosorption charges of hydrogen ion (QH) and the peak current density (IP) of the samples in the cyclic voltammetry (CV) curves. The magnitude of peak current density is positive correlation to the temperature. However, the CO tolerance, indicated that the better CO tolerance contributed to the less Pt replace on Ru cluster, which allow the Ru oxidizing CO to CO2 efficiently, is negative correlation-- to the temperature. The sample of 50 °C shows the better combination catalyst efficiency between the CO tolerance and the electrochemical performance.