Synthesis and Evaluation of the A-site Deficient Perovskite La_(0.65)Sr_(0.3)Cr_(0.85)Ni_(0.15)O_(3-δ) as Fuel Electrode for High Temperature Co-electrolysis Enhanced by In Situ Exsolution of Ni Nanoparticles

摘要

Lanthanum strontium chromite (LSC) perovskite partially doped with 15% of Ni on the B-site as reducible transition metal was investigated with the aim to perform in situ exsolution under reducing conditions. A-site deficient compounds were formulated to enhance the exsolution of the electrocatalyst. Single phase is achieved with the formulation La_(0.65)Sr_(0.3)Cr_(0.85)Ni_(0.15)O_(3-δ) (L65SCN) and has been characterized by X-ray diffraction (XRD), Rietveld refinement and scanning electron microscopy (SEM). Exsolution was investigated under reducing conditions in which Ni exsolution was confirmed. Such electrocatalyst was implemented into an electrolyte-supported-cell (ESC) for early electrochemical investigation. Cells were manufactured by screen printing of composite L65SCN/CGO as fuel electrode and La_(0.58)Sr_(0.4)Fe_(0.8)Co_(0.2)O_(3-δ) (LSCF) as air electrode on CGO-3YSZ-CGO substrates. These cells were characterized in steam electrolysis at 930°C by Electrochemical Impedance Spectroscopy (EIS). Further microstructural engineering and fine tuning of the manufacturing parameters are essential for a practical use of this electroctalyst for H_2O/CO_2 co-electrolysis operation.