(619g) In-Situ Exsolution of Bimetallic Cofe Nanoparticles on (La,Sr)FeO3 Perovskite: Its Effect on Oxidative Coupling of Methane | AIChE

(619g) In-Situ Exsolution of Bimetallic Cofe Nanoparticles on (La,Sr)FeO3 Perovskite: Its Effect on Oxidative Coupling of Methane


Kim, J. - Presenter, The Ohio State University
Kim, Y. J., Yeungnam University
Ferree, M., The Ohio State University
Gunduz, S., The Ohio State University
Co, A., The Ohio State University
Kim, M., Yeungnam University
Ozkan, U., The Ohio State University
Refinement of shale gas over the past several decades has produced an abundance of methane that is typically wasted by the practice of gas flaring. Research efforts have focused on identifying catalysts that can utilize this surplus methane by the production of ethane and ethylene. One strategy is to use a membrane reactor for OCM operating at low partial pressures of oxygen. A further advantage of solid oxide cells is that electricity can be spontaneously generated during OCM.

We explored La0.7Sr0.2Co0.2Fe0.8O3 (LSCF) catalyst as an anode for oxidative coupling of methane to ethylene and propylene. The in-situ exsolution of bimetallic CoFe nanoparticles and the resultant improvement on the electrochemical performance of the LSCF cell for OCM was supportively verified by analysis of surface and bulk characteristics as well as DFT calculations.

LSCF underwent the structural transformation under reducing environment. The main XRD peaks of LSCF remained after 3 h of reduction (H2-Red-LSCF), but the additional features corresponding to bimetallic CoFe, La2FeO4, and La2O3 also emerged. Moreover, XRD patterns showed that the CH4-treated LSCF (CH4-Red-LSCF) experienced the same structural transformation as H2-Red-LSCF. TPD-DRIFTS using CO2 as a probe molecule were conducted on LSCF and Red-LSCF, and the results verified that the surface of Red-LSCF is more basic than that of LSCF and that reduction is an effective way of promoting the catalytic characteristics of LSCF for the activation of CH4. Moreover, in order to gain insight into the surface dynamics during CH4 activation, in-situ CH4-DRIFTS measurements were conducted on LSCF and Red-LSCF catalysts under CH4 atmosphere at 450oC. According to the results, CH4 coupling reaction to C2+ is competing with the oxidation of CH4 and the controlled oxygen supply is a key parameter for a selective conversion of CH4 on Red-LSCF.