Engineering a high-performance W-doped Sr_0.9Fe_0.67Ti_0.3Co_0.03O_3-δ hydrogen electrode for Solid Oxide Electrolysis Cells (SOECs)

Traditionally, Ni-based cermet fuel electrodes have been extensively utilized in Solid Oxide Electrolysis Cells (SOECs) for their excellent conductivity and catalytic properties. However, the development of alternative materials has gained attraction due to concerns over Ni's susceptibility to carbon deposition and long-term stability issues. To overcome this issue, we designed Sr_0.9Fe_0.67Ti_0.30Co_0.07O_3-δ (SFTC) and W-doped SFTC (SFTCW) via the sol-gel method and thoroughly characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TG-DSC), and electrochemical tests. The results reveal that the incorporation of W enhances the stability of the electrode material under both oxidizing and reducing conditions, with no impurity phases detected. Furthermore, W doping promotes the precipitation of Co–Fe alloy, preserves the original structure, and facilitates the creation of oxygen vacancies within the material. In a reducing atmosphere containing 40 % H₂O, SFTCW demonstrates superior electrolysis performance at an electrolysis voltage of 1.8 V, exhibiting a remarkable improvement of approx. 35 % compared to the SFTC sample. During a 100 h long-term stability test, the current density of SFTCW increased from -240 mA cm^–2 to -270 mA cm^–2, attributed to the enhanced hydrogen oxidation activity and increased reactive sites resulting from W doping, thereby enhancing its long-term stability. This work provides a feasible scheme for the selection and construction of hydrogen electrodes for electrolytic water.