Engineering and Characterization of Bi- and Trimetallic Nanocrystals for Catalysis in Model Ethanol Fuel Cells

Abstract

The electrocatalytic activity of nanocrystals composed of Pt, Rh, and Sn suspended on glassy carbon electrodes were investigated in a model direct ethanol fuel cell. The atomic ratios of Pt-Rh bimetallic catalysts were varied in the micelles synthesis procedure to explore the most efficient electrooxidation of ethanol. Pt nanocrystals were first synthesized as a control. Pt-Rh bimetallic nanocrystals were synthesized in molar compositions of 2:3, 3:1, and 4:1. A Pt-Rh-Sn trimetallic nanostructured catalyst was synthesized in an atomic composition 3:2:1. The nanocrystals were characterized physically using Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray (EDX) Analysis. From the TEM data, the average size of the produced nanocrystals was determined to be 5nm. Each sample was characterized electrochemically using cyclic voltammetry (CV). From the CV data, Rh concentrations of over 20% resulted in lower current densities than solely Pt, while the 4:1 Pt-Rh ratio had 2.32x more catalytic activity. The ternary nanocrystals resulted with 4.1x higher current density, proving to be the most active catalyst of the study.