Oxygen evolution behavior of La1−xSrxFeO3−δ electrodes in LiCl–KCl melt

Abstract

AbstractElectrochemical 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