Improved Anode Catalyst for Formic Acid Fuel Cells

Abstract

The use of direct formic acid fuel cells (DFAFCs) in portable electronic devices can improve available power density and convenience, compared to today’s rechargeable batteries. Unfortunately, current DFAFC anode catalysts either have high parasitic overpotentials and/or deactivate over time. This deactivation causes a decrease in sustained performance of the catalyst over time. A typical anode catalyst used in these DFAFC consists of carbon supported platinum nanoparticles with a sub-monolayer of bismuth (Pt/C-Bi). Over time, bismuth is oxidized and lost from surface resulting in deactivation of the catalyst nanoparticles, which leads to the DFAFC losing performance. Initial studies with citrate have demonstrated strong surface adsorption to Pt. Linear sweep voltammetry in formic acid shows minimal electro-oxidation performance on pure Pt and a full monolayer of citrate. However, for a submonolayer of citrate the activation overpotential is reduced to 0.2 V vs. RHE due to the significant contribution to the direct reaction pathway. The goal of this project is to continue exploring stable alternative adsorbates to replace bismuth in order to maximize power density and durability of DFAFCs.