Cobalt-free SrFe_0.9Ti_0.1O_3-δ as a high-performance electrode material for oxygen reduction reaction on doped ceria electrolyte with favorable CO₂ tolerance

A cobalt-free titanium-doped SrFeO_3-δ perovskite with a nominal composition of SrFe_0.9Ti_0.1O_3-δ (SFT) is exploited as an alternative electrode for solid oxide fuel cells (SOFCs). Special attention is given to the effects of CO₂ on the oxygen reduction reaction (ORR) performance and properties of the oxide. For this investigation, XRD, HR-TEM, FT-IR, 4-probe DC conductivity, EIS and SEM are used. Although no bulk carbonate is formed, even under a pure CO₂ atmosphere, the chemical adsorption of CO₂ only appears over the SFT surface, which suggests a weak effect of CO₂ on the structure of SFT. The EIS tests demonstrate that such CO₂ adsorption does have a modest and detrimental effect on the ORR over the SFT electrode. However, the electrochemical performance can be easily recovered after removing of CO₂. Thus, SrFe_0.9Ti_0.1O_3-δ is a promising cathode material for practical SOFCs due to its high activity, high CO₂ tolerance, and low cost.