Atomistic Insights into Medium-Entropy Perovskites for Efficient and Robust CO₂ Electrolysis

Solid oxide electrolysis cells (SOECs) show great promise in converting CO2 to valuable products. However, their practicality for the CO2 reduction reaction (CO2RR) is restricted by sluggish kinetics and limited durability. Herein, we propose a novel medium-entropy perovskite, Sr2(Fe1.0Ti0.25Cr0.25Mn0.25Mo0.25)O6−δ (SFTCMM), as a potential electrode material for symmetrical SOEC toward CO2RR. Experimental and theoretical results unveil that the configuration entropy of SFTCMM perovskites contributes to the strengthened metal 3d–O 2p hybridization and the reduced O 2p bond center. This variation of electronic structure benefits oxygen vacancy creation and diffusion as well as CO2 adsorption and activation and ultimately accelerates CO2RR and oxygen electrocatalysis kinetics. Notably, the SFTCMM-based symmetrical SOEC delivers an excellent current density of 1.50 A cm–2 at 800 °C and 1.5 V, surpassing the prototype Sr2Fe1.5Mo0.5O6−δ (SFM, 1.04 A cm–2) and most of the state-of-the-art electrodes for symmetrical SOECs. Moreover, the SFTCMM-based symmetrical SOEC demonstrates stable CO2RR operation for 160 h

Boosting the Electrocatalytic Activity of Pr_0.5Ba_0.5FeO_3−δ via Ni Doping in Symmetric Solid Oxide Electrolysis Cells

Symmetric solid oxide electrolysis cells (SSOECs) have garnered significant scientific interest due to their simplified cell architecture, robust operational reliability, and cost-effectiveness, for which a highly electrocatalytically active electrode is the decisive main factor. This work evaluates the electrochemical performance of Ni-doped Pr0.5Ba0.5FeO3−δ (PBF) perovskite materials, with a focus on Pr0.5Ba0.5Fe0.8Ni0.2O3−δ (PBFN). The experimental findings herein prove the exceptional electrocatalytic ability of PBFN in facilitating the oxygen evolution and carbon dioxide reduction reaction, surpassing the electrochemical performance of PBF. In addition, the PBFN symmetric cell has excellent performance for CO2 electrolysis, and the cell has a low polarization resistance value of 0.1 Ω·cm2. Moreover, it achieves an impressive current density value of 1.118 A·cm–2 under operating conditions of 2.0 V and 800 °C, which is superior to those of the PBF symmetric cell and the PBFN asymmetric cell. It also has a good structural and performance stability. These results imply a bright development prospect of PBFN as electrodes for SSOECs