Perovskite LaFeO3 supported bi-metal catalyst for syngas methanation

Abstract

LaFeO₃ perovskite supported Ni and Ni-Fe catalysts were prepared and applied to methanation reaction of syngas. Two preparation methods were employed. One was one-step citrate complexing method, and the other was a two step method using citrate complexing method to produce LaFeO₃ and followed by loading nickel oxide on it with impregnation. The structure evolution of the sample as prepared was investigated by XRD, TPR and TEM techniques. For the former, the chemical composites of the calcined sample are NiO-Fe₂O₃/LaFe_1–xNi_xO₃. After reduction and reaction of CO methanation, its composites convert to Fe-Ni@Ni/LaFeO₃-La₂O₂CO₃, in which Fe-Ni@Ni is metal particles in nano-size composed of nickel core and Fe-Ni alloy shell. For the latter, the chemical composites of the calcined sample are NiO/LaFeO₃; and after reduction and reaction of CO methanation, its chemical composites change to Ni/LaFeO₃. Ni/LaFeO₃ catalyst is a little more active, while Fe-Ni@Ni/LaFeO₃-La₂O₂CO₃ is much more stable and shows very good resistance to carbon deposition. In this work it is aimed to show that the structure and composites of the catalysts can be tailored using perovskite-type oxide as precursor prepared with different methods and conditions. Therefore, it is a promising route to prepare supported bi-metal catalysts in nano-size for a lot of metals with desired catalytic performances.