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

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 C 2+ hydrocarbons and C 3 H 6 , respectively. DFT calculations on LSCF and CoFe revealed that the high selectivity of C 2+ hydrocarbons on the LSCF primarily stems from the presence of CoFe nanoparticles. In-situ DRIFTS conducted under CH 4 proved that complete oxidation of CH 4 can be effectively inhibited by reducing LSCF, and control of oxygen supply is an important parameter for selective conversion of CH 4 to higher order hydrocarbon. • Reduction of LSCF under H 2 or CH 4 caused exsolution of CoFe nanoparticles. • LSCF cell worked either in ion pump or in fuel cell mode for electrocatalytic OCM. • Highest C 2+ selectivity of 63% and C 3 H 6 selectivity of 10.2% were achieved for OCM. • DFT calculations revealed the high selectivity for OCM arises from CoFe alloy. • DRIFTS under CH 4 showed oxygen supply is critical to selective conversion of CH 4 .