Bifunctional barium cerate catalyst doped with Fe for enhanced electrochemical stability during oxygen reduction and evolution reactions

Electrocatalysts are considered indispensable to achieve water splitting efficiently and, in this way, enable the green hydrogen economy during the decarbonization of primary processes. In this work, the barium cerate catalyst doped with Fe (BaCe0.5Fe0.5O3) was synthesized using the modified Pechini method followed by heat treatment. The obtained composite was physicochemically characterized. Furthermore, its electrochemical activity for the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) was assessed by conducting cyclic voltammetry (CV) and linear sweep voltammetry (LSV) in alkaline media. The XRD and TEM reveals the presence of cubic and orthorhombic dual perovskite phases with crystallite size below 50 nm. The FESEM analysis exhibited dumbbell-like and spherical close-packed particles. Meanwhile, EDS results confirm the presence of Ba, Fe, Ce, and O distributed evenly along the surface of the composite. XPS reveals the presence of Ce3+, Ce4+ and Fe2+, Fe3+, all of which play a crucial role in the catalytic activity of the reactions. The OER demonstrates a significant improvement after 3000 cycles attributed to the reconstruction that occurred in the electrocatalyst with an Eonset of 1.41 at 1.39 V vs RHE before and after ADT, and an overpotential of 620 mV at 5 mA cm-2. The electrochemical parameters achieved during the ORR are comparable to those reported in the literature, i.e., a half-wave close to 0.71-1.69 V before and after ADT, respectively, and a current density of 3.15 mA cm-2 at 0.2 V. Additionally, BaCe0.5Fe0.5O3 electrocatalyst exhibited greater stability after the ADT test. Thus, the studied Fe-doped BaCeO3 perovskite contributes positively to the catalytic activity of OER and ORR. This work provides new insight for developing cost-effective and efficient electrocatalysts that can be used for water splitting and oxygen reaction processes.