Musa Najimu1,Matthew Hurlock2,Tina Nenoff2,Jonas Baltrusaitis3,Kandis Abdul-Aziz1
University of California, Riverside1,Sandia National Laboratories2,Lehigh University3
Musa Najimu1,Matthew Hurlock2,Tina Nenoff2,Jonas Baltrusaitis3,Kandis Abdul-Aziz1
University of California, Riverside1,Sandia National Laboratories2,Lehigh University3
The structural reversibility of smart exsolved nanoparticle catalysts offer the opportunity for SOEC application in reversible modes, however, structural reversibility in the presence of anthropogenic contaminant poisoning is important for nonideal SOEC conditions. In addition to redirecting the reaction pathways and lowering the selectivity, this contaminant poisoning can lower the overall conversion of the carbon feeds due to the preferential conversion of the contaminants. Sulfur removal in H<sub>2</sub>S-poisoned perovskite materials as well as the restoration of the activity of the poisoned materials, is typically achieved by oxidative treatment at 800 <sup>o</sup>C. Here, the structural changes of SOx-poisoned NiFe/LaFe<sub>0.9</sub>Ni<sub>0.1</sub>O<sub>3</sub> (LFNO) material were tracked for regenerability using cycling dry methane reforming (DRM) experiments to assess the intrinsic regenerability. While reduction of as-prepared LFNO facilitates the exsolution of NiFe with the formation of La<sub>2</sub>O<sub>3</sub> and La(OH)<sub>3</sub>, DRM causes partial reincorporation of the exsolved NiFe nanoparticle. The exsolved nanoparticle demonstrates structural recyclability as oxidation after DRM reincorporates the NiFe nanoparticle back into the LFNO perovskite, while subsequent reduction causes the re-exsolution of the NiFe alloy nanoparticle. In addition, the DRM activity after the regeneration closely matches the DRM activity of freshly reduced LFNO perovskite, further demonstrating the reversibility of the exsolved NiFe/LFNO. However, using the same regeneration condition, the deteriorated DRM activity of the NiFe/LFNO material exposed to SOX at 600 <sup>o</sup>C is not restored, possibly demonstrating the prohibitory effect of SOx exposure for regeneration. In addition to a direct comparison of the impact of the type of sulfur contaminant species on regeneration, the speciation of sulfur on the exsolved nanoparticle systems as well as the regeneration of this novel SOEC candidate will be discussed.