Preparation and characterization of Pt-Sn/C and Pt-Ir/C catalysts for the electrochemical oxidation of ethanol in polymer electrolyte membrane fuel cell

Abstract

Low temperature fuel cells with methanol or ethanol as the fuel represent an environmentally friendly technology and are attracting considerable interest as a means of producing electricity. High surface area carbon supported Pt is recognised to be the most active metal for ethanol oxidation, however the formation of CO-intermediates poison the Pt catalyst. Literature studies have indicated that the modification of platinum by tin gives the more pronounced enhancement. Pt-Sn/C activity for ethanol oxidation is still low. Development of new active catalysts able to break C-C bond and complete oxidation of ethanol into CO2 is of fundamental importance. Generally, a third metal is added to the best binary Pt-Sn catalyst to improve CO tolerance and activity. In this study binary Pt-Sn/C and ternary Pt-Sn-Ir/C electrocatalyst were synthesized by reduction of the metal precursors using two different methods, namely formic acid and electrochemical deposition methods. The catalysts were characterised by EDX, XRD and TEM. The electrochemical active area was determined by cyclic voltammetry. The activities of these catalysts towards ethanol oxidation were compared to the commercial Pt/C