In-situ exsolution of bimetallic CoFe nanoparticles on (La,Sr)FeO3 perovskite: Its effect on electrocatalytic oxidative coupling of methane

• Published in: Applied catalysis. B, Environmental Vol. 321; no. C
• Main Authors: Kim, Jaesung, Kim, Yu Jin, Ferree, Matthew, Gunduz, Seval, Co, Anne C., Kim, Minkyu, Ozkan, Umit S.
• Format: Journal Article
• Language: English
• Published: United States Elsevier 04.10.2022
• Subjects: Chemistry; ENGINEERING; Exsolution; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Oxidative coupling of methane; Perovskite; Solid oxide cell
• ISSN: 0926-3373

This study presents in-situ reduction of lanthanum strontium cobalt ferrite (LSCF) perovskite as an effective method for modifying its surface properties and enhancing its electrocatalytic reactivity for oxidative coupling of methane (OCM). The evolution of hetero-phases during the reduction of LSCF resulted in CoFe nanoparticles being formed at the surface. The in-situ reduced LSCF cell for OCM could be operated in either an ion pump or a fuel cell mode. High selectivity of 63% and 10.2% were reported for C2+ hydrocarbons and C3H6, respectively. DFT calculations on LSCF and CoFe revealed that the high selectivity of C2+ hydrocarbons on the LSCF primarily stems from the presence of CoFe nanoparticles. In-situ DRIFTS conducted under CH4 proved that complete oxidation of CH4 can be effectively inhibited by reducing LSCF, and control of oxygen supply is an important parameter for selective conversion of CH4 to higher order hydrocarbon.