Novel high-entropy perovskite-type symmetrical electrode for efficient and durable carbon dioxide reduction reaction

Excessive emission of carbon dioxide (CO2) has posed an imminent threat to human's environment and global prosperity. To achieve a sustainable future, solid oxide electrolysis cell (SOEC), which can efficiently combine CO2 reduction reaction (CO2RR) and renewable energy storage, has become increasingly attractive owing to its unique functionalities. Additionally, symmetrical SOEC (SSOEC) has been considered as one of the most versatile cell configurations due to its simplified process, high compatibility, and low cost. However, the electrode material requirements become very demanding since efficient catalytic-activities are required for both CO2RR and oxygen evolution reaction (OER). Herein, we demonstrate a novel high-entropy perovskite type symmetrical electrode Pr0.5Ba0.5Mn0.2Fe0.2Co0.2Ni0.2Cu0.2O3-δ (HE-PBM) for SSOEC. B-site doping of transition metals such as Mn, Fe, Co, Ni, and Cu in HE-PBM anode has been found to strongly accelerate the OER in the anode. Moreover, the presence of in-situ formed Fe–Co–Ni–Cu quaternary alloy nanocatalysts from HE-PBM cathode under reducing atmosphere has resulted in superior catalytic-activity towards CO2RR. The faster kinetics are also reflected by the significantly low polarization resistance of 0.289 ​Ω⋅cm2 and high electrolysis current density of 1.21 ​A⋅cm−2 for CO2RR at 2.0 ​V and 800 ​°C. The excellent electrochemical performance and stability demonstrate that the high-entropy perovskite material is a promising electrode material in SSOEC for efficient and durable CO2RR.