Nickel exsolution driven phase transformation from an n=2 to an n=1 Ruddlesden Popper manganite for methane steam reforming reaction in SOFC conditions

This is the peer reviewed version of the following article: S. Vecino-Mantilla, P. Gauthier-Maradei, M. Huvé, J. M. Serra, P. Roussel, G. H. Gauthier, ChemCatChem 2019, 11, 4631, which has been published in final form at https://doi.org/10.1002/cctc.201901002. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] An original way to perform the exsolution of Ni nanoparticles on a ceramic support was explored for the development of methane steam reforming catalyst in SOFC anode conditions. The n=2 Ruddlesden-Popper (RP) phase La1.5Sr1.5Mn1.5Ni0.5O7 +/-delta has been synthesized by the Pechini method and subsequently reduced with an H-2-N-2 mixture at different temperatures and reducing times to induce the formation of two phases: LaSrMnO4 (n=1 RP) decorated with metallic Ni nanoparticles. Preliminary measurements of catalytic behavior for the steam reforming have been carried out in a reduction-reaction process with a mixture of 82 mol %CH4, 18 mol %N-2 and low steam to carbon ratio (S/C=0.15). The catalyst exhibits a selectivity for CO production (0.97), 14.60 mol % CH4 conversion and around 24.19 mol % H-2 production. Such catalytic behavior was maintained for more than 4 h, with a constant rate of hydrogen production and CH4 conversion rate.The authors acknowledge the financial support of the Colombian Administrative Department of Science, Technology and Innovation COLCIENCIAS (Project #110265842833 "Symmetrical high temperature Fuel Cell operating with Colombian natural gas" (contract #038-2015) and S. Vecino-Mantilla's Ph.D. scholarship (call #647)) and of the Spanish National Research Council CSIC (Project #COOPA20112). The authors are also grateful to UIS' X-Ray Laboratory (Parque Tecnologico Guatiguara) for XRD measurements, UPV's Electronic Microscopy Laboratory for the FESEM analysis, and finally to Margarita Vecino-Mantilla, Carolina Cardenas-Velandia, Santiago Paez-Duque, Ivan Suarez-Acelas (UIS), Maria Fabuel (UPV) and Olivier Gardoll (UCCS) for their contribution to materials synthesis and characterization. As well as Santiago Palencia, Monica Sandoval (UIS) and Caroline Pirovano (UCCS) are warmly acknowledged for useful discussions.Vecino-Mantilla, S.; Gauthier-Maradei, P.; Huvé, M.; Serra Alfaro, JM.; Roussel, P.; Gauthier, GH. (2019). Nickel exsolution driven phase transformation from an n=2 to an n=1 Ruddlesden Popper manganite for methane steam reforming reaction in SOFC conditions. ChemCatChem. 11(18):4631-4641. https://doi.org/10.1002/cctc.201901002S463146411118Ghezel-Ayagh, H., & Borglum, B. P. (2017). Review of Progress in Solid Oxide Fuel Cells at FuelCell Energy. 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Nickel exsolution-driven phase transformation from an n=2 to an n=1 ruddlesden-popper manganite for methane steam reforming reaction in sofc conditions

International audienceAn original way to perform the exsolution of Ni nanoparticles on a ceramic support was explored for the development of methane steam reforming catalyst in SOFC anode conditions. The n=2 Ruddlesden-Popper (RP) phase La1.5Sr1.5Mn1.5Ni0.5O7±δ has been synthesized by the Pechini method and subsequently reduced with an H2-N2 mixture at different temperatures and reducing times to induce the formation of two phases: LaSrMnO4 (n=1 RP) decorated with metallic Ni nanoparticles. Preliminary measurements of catalytic behavior for the steam reforming have been carried out in a reduction-reaction process with a mixture of 82 mol %CH4, 18 mol %N2 and low steam to carbon ratio (S/C=0.15). The catalyst exhibits a selectivity for CO production (0.97), 14.60 mol % CH4 conversion and around 24.19 mol % H2 production. Such catalytic behavior was maintained for more than 4 h, with a constant rate of hydrogen production and CH4 conversion rate