PEROVSKITE ANODE ELECTROCATALYSIS FOR DIRECT METHANOL FUEL-CELLS

This investigation explores direct methanol fuel cells incorporating perovskite anode electrocatalysts. Preliminary electrochemical performance was addressed following incorporation of electrocatalysts into polymer electrolyte (Nafion 417) fuel cells. Perovskite electrocatalysts demonstrating activity towards direct methanol oxidation during cyclic voltammetry measurements included, respectively, SrRu0.5Pt0.5O3, SrRu0.5Pd0.5O3, SrPdO3, SmCoO3, SrRuO3, La0.8Ce0.2CoO3, SrCo0.5Ti0.5O3, and La0.8Sr0.2CoO3 where SrRu0.5Pt0.5O3 gave methanol oxidation currents up to 28 mA/cm2 at 0.45 V vs. SCE. Correlations were found between electrocatalyst solid-state and thermodynamic parameters corresponding to, respectively, molecular electronic polarizability (alpha), the optical dielectric constant (epsilon), the perovskite spin-only magnetic moment (I(s)), the number of d-electrons in perovskite A and B lattice sites (n(d)), and the average metal-oxygen binding energy for the perovskite lattice (E(M-O)), and corresponding fuel cell performance. This may have future merit for the prediction of new electrocatalyst family members for promoting direct methanol oxidation. Methanol diffusion from anode to cathode compartments appears to be a major obstacle to the development of polymer electrolyte methanol fuel cells.