Perovskite titanate cathode decorated by in-situ grown iron nanocatalyst with enhanced electrocatalytic activity for high-temperature steam electrolysis

The use of perovskite titanate as composite cathode for direct steam electrolysis has demonstrated promising performances due to its unique specific redox-stable properties. However, the insufficient electro-catalytic activity of the perovskite titanate remains a major setback that inhibits the electrode performance. This study addresses the drawbacks and reports an investigation of iron doped titanate (La0.2Sr0.8)0.9Ti0.9Fe0.1O3-δ (LSTFO), which can be reduced to in-situ grown iron nano-catalyst on substrate, as a potential composite cathode for steam electrolysis in a solid oxide electrolyser. Results of XRD, SEM, EDS, XPS and TGA analysis together confirm that the exsolution and dissolution of the iron nanoparticles is completely reversible in redox treatment cycles. The electrical properties of the LSTO and LSTFO are investigated and correlated to the performances of the composite electrodes. The presence of exsolved iron nanocatalyst significantly enhanced the polarizations of the symmetrical and electrolysis cells of the LSTFO composite electrode. The synergetic effect of catalytically-active iron and redox-stable LSTO produced excellent short-term stability of the cathode with attendant efficient electrochemical reduction of steam and remarkable enhancement of Faraday efficiency by about 100%.