B‐Site‐Dependent Catalytic Performance in La _0.7 Sr _0.3 BO _3‐δ Anodes for Methane‐Assisted High T

ABSTRACT

This study presents a comparative investigation of La _0.7 Sr _0.3 BO _3‐δ , (LSB with B═Co, Fe, Cr) anodes for methane assisted high temperature electrolysis (HTE). Simultaneous electrochemical characterization and outgas monitoring helps clarifying the structure‐performance‐selectivity relationships of these perovskites when operating under methane atmosphere. The depolarization of electrolysis cell by methane oxidation at the anode is evidenced in different experiments. Findings reveal that LSFe and LSCo undergo significant activation under methane, driven by B‐site metal segregation and increased surface defects, which enhance their electrochemical performances. In contrast, LSCr demonstrates superior stability but limited depolarization benefit. Two distinct regimes were observed under anodic methane flow: partial oxidation of methane (POM) associated with low cell voltage (below OER defined potential) at low currents and total oxidation of methane (TOM) with markedly increased cell voltage (above OER defined potential), when higher currents were applied. The limit current marking the shift from POM‐dominated to TOM‐dominated regimes depends on perovskite B site element, methane partial pressure and provides a performance assessment of methane assisted HTE anode systems.