Orthorhombic Y0.95-xSrxCo0.3Fe0.7O3-δ anode for oxygen evolution reaction in solid oxide electrolysis cells

Cubic perovskite oxides usually suffer from delamination and Sr2+ segregation for catalyzing oxygen evolution reaction (OER) at the anodes of solid oxide electrolysis cells (SOECs). It is crucial to develop alternative and efficient anode materials for SOECs. Herein, a series of novel Y0.95-xSrxCo0.3Fe0.7O3-δ (YSCF-x) orthorhombic perovskite oxides in the Pnma (62) space group are synthesized as anode materials of SOECs. Physicochemical characterizations and density functional theory calculations reveal that the partial substitution of Y3+ by Sr2+ increases the oxygen vacancy concentration and mobility as well as improves the electrical conductivity, which contributes to the excellent OER activity of YSCF-x. At 800 °C, the current density of SOEC with YSCF-0.05-Ce0.8Sm0.2O2-δ anode can reach 1.32 A cm−2 at 1.6 V, about twice that of SOEC with Y0.95Co0.3Fe0.7O3-δ-Ce0.8Sm0.2O2-δ anode. This work paves a new avenue for the design of advanced anode materials of SOECs. Description: Orthorhombic perovskite oxides Y0.95-xSrxCo0.3Fe0.7O3-δ are investigated as anode materials of SOECs. Sr2+ doping increases the oxygen vacancy concentration and mobility as well as the electrical conductivity of Y0.95-xSrxCo0.3Fe0.7O3-δ, which significantly enhances the oxygen evolution reaction activity of SOECs. [Display omitted]