Perovskite materials are typically used as oxygen electrodes of solid oxide fuel and electrolysis cells (SOC). The high stability of the perovskite structure in oxidative environments makes it a good candidate as a cathode electrode for steam electrolysis SOC as well. In this work, we investigate SOC with La_0.75Sr_0.25Cr_0.9Fe_0.1O₃ perovskite cathodes employing near ambient pressure X-ray photoelectron and near-edge X-ray absorption fine structure spectroscopies combined with online electrochemical measurements. Based on operando experimental evidences the surface state of the perovskite electrode is directly associated with the electrocatalytic performance of the cell. The results indicate that under steam electrolysis operating conditions the well-known Sr surface enrichment is accompanied by Cr segregation and formation of SrCrO₄-like oxide. In contrast to the common perception of the role of surface chromites, we show here that its presence does not induce cell deactivation, but on the contrary, is beneficial for cell performance.

钙钛矿材料通常用作固体氧化物燃料和电解池（SOC）的氧电极。钙钛矿结构在氧化环境中的高稳定性使其成为蒸汽电解SOC阴极的良好候选者。在这项工作中，我们研究了La _0.75 Sr _0.25 Cr _0.9 Fe _0.1 O _3的SOC。钙钛矿阴极采用近环境压力X射线光电子和近边缘X射线吸收精细结构光谱学，以及在线电化学测量方法。基于操作实验证据，钙钛矿电极的表面状态与电池的电催化性能直接相关。结果表明，在蒸汽电解操作条件下，众所周知的Sr表面富集伴随着Cr偏析和SrCrO ₄样氧化物的形成。与表面亚铬酸盐作用的一般认识相反，我们在这里表明其存在不会诱导细胞失活，但相反，对细胞性能是有益的。