Electrochemical reduction processes of oxides in molten salt have been proposed as the carbon-free technologies in order to achieve carbon neutrality. The anodic behavior of La1−xSrxFeO3−δ as an O2 evolution anode in LiCl–KCl at 723 K was investigated. The results suggested that at 723 K, the electrical conductivity of La1−xSrxFeO3−δ tended to increase with the Sr doping. The anodic reactions of the La1−xSrxFeO3−δ electrodes were characterized by electrochemical measurements in LiCl–KCl + Li2O at 723 K. Based on the cyclic voltammograms of the La0.7Sr0.3FeO3−δ electrode, O2 evolution has proceeded between 2.7 and 3.6 V. The potential of the La0.7Sr0.3FeO3−δ electrode during galvanostatic electrolysis has conducted at 39 mA cm−2 for 15 h has remained stable at 2.8 V, indicating that the stable evolution of O2 gas was monitored. The corrosion rate was estimated to have the low value of 8.6 × 10−4 g cm−2 h−1. Electrode surface data obtained after electrolysis indicated that the La0.7Sr0.3FeO3−δ electrode exhibited excellent chemical and physical stability in LiCl–KCl at 723 K. This indicates that the La0.7Sr0.3FeO3−δ electrode is promising candidate material as inert anodes for oxide decomposition. As an application of the La0.7Sr0.3FeO3−δ electrode, the electrolytic reduction of CO2 was also successfully achieved. Graphical Abstract

Electrochemical reduction processes of oxides in molten salt have been proposed as the carbon free technology in order to achieve carbon neutral. The anodic behavior of La1−xSrxFeO3−δ as an oxygen-evolution anode in LiCl−KCl at 723 K is investigated. Data suggests that at 723 K, the electrical conductivity of La1−xSrxFeO3−δ tends to increase as the extent of Sr doping. The anodic reactions of La1−xSrxFeO3−δ electrodes are characterized by electrochemical measurements in LiCl−KCl + Li2O at 723 K. Based on the cyclic voltammograms of the La0.7Sr0.3FeO3−δ electrode, oxygen evolution has proceeded between 2.7 V and 3.6 V. The potential of La0.7Sr0.3FeO3−δ electrode during galvanostatic electrolysis has conducted at 39 mA cm-2 for 15 h has remained stable at 2.8 V, indicating that the stable evolution of oxygen gas is monitored. The corrosion rate is estimated to have the low value of 8.6 × 10−4 g cm−2 h−1. Electrode surface data collect after electrolysis indicate that La0.7Sr0.3FeO3−δ electrode has excellent chemical and physical stability in LiCl−KCl at 723 K. Evidence thus indicates that La0.7Sr0.3FeO3−δ electrode is a promising candidate material as inert anodes for oxides decomposition. As one of application of the La0.7Sr0.3FeO3−δ electrode, the electrolysis reduction of CO2 was also successfully achieved.

Electrochemical reduction processes of oxides and injected CO2 in molten salt have been paid much attention as the carbon free technology to achieve the SDGs. We focused on La1− x Sr x FeO3− δ materials to utilizing O2 evolution electrode, because they intrinsically possess both oxygen ion conductivity and electron conductivity at elevating temperatures. Unfortunately, the properties have not been well examined in the molten salt despite the fundamental characteristics for the application to the inert anode. We found that La1− x Sr x FeO3− δ electrodes had excellent chemical and physical stability for keeping stable oxygen evolution reaction in the molten chlorides at 723 K.