A Study of the Ethanol Oxidation Kinetics and Product Distribution using a Pt/TOMS Electrocatalyst

Abstract

Ethanol is an abundant and sustainable fuel that power direct ethanol fuel cells (DEFCs). In a DEFC, the ethanol oxidation reaction (EOR) proceeds at the anode while the oxygen reduction reaction occurs at the cathode. Conventional DEFC electrocatalysts are composed of platinum nanoparticles deposited onto a carbon support (Pt/C). The slow kinetics of the EOR on Pt/C ultimately limits cell performance. Thus, researchers have been looking to develop new catalyst materials that are more stable and active than Pt/C. Here we present a carbon-free catalyst composed of platinum nanoparticles deposited onto a Ti3O5Mo0.2Si0.4 support (Pt/TOMS). The unique metal oxide support is highly conductive and has a strong electronic interaction with the platinum nanoparticles which leads to excellent activity towards the EOR. In comparison to a Pt/C catalyst, Pt/TOMS exhibits earlier onset potentials and a higher current density. Pt/TOMS also shows smaller charge transfer resistance values of 778Ω − 90Ω compared to 818Ω − 206Ω for Pt/C, over a range of temperatures. Activation energies were also lower for Pt/TOMS, ranging from 11.1 J mol−1 to 28.6 J mol−1 compared to 14.5 J mol−1–33.7 J mol−1 for Pt/C. For these reasons, Pt/TOMS is proposed as a more suitable catalyst material for use in DEFCs.