Enhanced CO<sub>2</sub> Electrolysis Through Mn Substitution Coupled with Ni Exsolution in Lanthanum Calcium Titanate Electrodes
Nuoxi Zhang, Aaron B. Naden, Lihong Zhang, Xiaoxia Yang, Paul A. Connor, John T. S. Irvine
Abstract
Abstract In this study, perovskite oxides La 0.3 Ca 0.6 Ni 0.05 Mn x Ti 0.95− x O 3− γ ( x = 0, 0.05, 0.10) are investigated as potential solid oxide electrolysis cell cathode materials. The catalytic activity of these cathodes toward CO 2 reduction reaction is significantly enhanced through the exsolution of highly active Ni nanoparticles, driven by applying a current of 1.2 A in 97% CO 2 – 3% H 2 O. The performance of La 0.3 Ca 0.6 Ni 0.05 Ti 0.95 O 3−γ is notably improved by co‐doping with Mn. Mn dopants enhance the reducibility of Ni, a crucial factor in promoting the in situ exsolution of metallic nanocatalysts in perovskite (ABO 3 ) structures. This improvement is attributed to Mn dopants enabling more flexible coordination, resulting in higher oxygen vacancy concentration, and facilitating oxygen ion migration. Consequently, a higher density of Ni nanoparticles is formed. These oxygen vacancies also improve the adsorption, desorption, and dissociation of CO 2 molecules. The dual doping strategy provides enhanced performance without degradation observed after 133 h of high‐temperature operation, suggesting a reliable cathode material for CO 2 electrolysis.