A novel family of W-doped Bi0.5Sr0.5FeO3-δ perovskite as oxygen electrode catalyst for CO2 electrolysis in solid oxide electrolysis cells

Abstract

Co-free Bi0.5Sr0.5FeO3-δ perovskite as a novel oxygen electrode shows good electrochemical performance for solid oxide electrolysis cells (SOECs). In this work, W-doped Bi0.5Sr0.5Fe1-xWxO3-δ (BSFWx, x = 0, 0.05, 0.1, and 0.15) perovskite oxides were prepared and evaluated for CO2 electrolysis in SOECs to further promote its oxygen catalytic activity. All the samples maintain a single-phase structure, and the BSFW0.1 sample presents the lowest polarization resistance value of about 0.067 Ω cm2, which is 47 % smaller than that of the BSF sample. Moreover, the BSFW0.1 half-cell exhibits good stability for 84 h under 0.5 A cm−2 anodizing polarization at 800 °C. The fuel electrode-supported BSFW0.1 single cell reaches a current density of 0.63 A cm−2, which is an improvement of approximately 33.8 % compared with of BSF under 1.5 V when the temperature and feed gas are 800 °C and 50 % CO2–50 % CO, respectively. This prominent performance is ascribed to creating more oxygen vacancies concentration by W doping, which promotes the transport of oxygen species. These outstanding electrochemical properties demonstrate that BSFW0.1 oxide is a promising potential oxygen electrode electrocatalyst for CO2 electrolysis in SOECs.