Synthesis of active electrocatalysts using glycine–nitrate chemistry

Abstract

Due to sluggish oxygen reduction reactions, development in the solid oxide fuel cell (SOFC) field is stagnant. Two solutions, increasing the active surface or use of precious materials, can stimulate the oxygen reduction kinetics on electrodes. Thus, to gain both these benefits, the present article addressed the synthesis of high surface-area mixed oxide ionic–electronic conductor La0.6Sr0.4Co0.8Fe0.2O3-δ (LSCF) using chemistry of the propellant glycine–nitrate reaction. In this study, different fuel to oxidant ratios (ψ), 2.0, 2.6, and 3.0 were used to control the exothermicity of reaction and powder properties. The maximum reaction temperature of 1337 K at ψ = 3.0 resulted in coarsened powder. In contrast, comparatively less exothermicity of reaction at ψ = 2.0 resulted in powder with substantial Brunauer–Emmett–Teller surface area of 10.97 m2 g−1, with maximum powder compaction achieved at sintering of 1273 K. With optimal direct current in-plane electrical conductivity of 341 S cm−1, H2-temperature-programmed reduction showed excellent catalytic activity for the sample obtained at ψ = 2.0. The electrochemical performance comparisons of electrodes in two different cell geometries – with and without a gold catalytic current collecting layer (Au–CCCL) – revealed the least polarization and cell resistance in the cell with Au–CCCL. The electrode area specific resistance and cell conductivity using Au–CCCL were 0.097 Ω cm−2 and 0.15 S cm−1, respectively.