Porous LaFeO3 perovskite catalysts synthesized by different methods and their high activities for CO oxidation

Abstract

In this study, spherical α-Fe₂O₃ prepared by the hydrothermal method was used as a template for the first time; LaFeO₃ perovskite catalysts were successfully synthesized by the molten salt method (M-LF-T), sol–gel method (S-LF-T), and co-precipitation method (C-LF-T), respectively. To determine the optimal synthesis method, X-ray diffraction patterns were obtained and showed that single phase LaFeO₃ with good crystallinity was prepared by the molten salt method after calcination at 600 °C for 4 h. SEM and TEM images showed that the M-LF-600 catalyst preserved the spherical structure of α-Fe₂O₃ template. Compared with the catalysts synthesized by the sol–gel method and co-precipitation method, the M-LF-600 catalyst had the highest BET surface area of 16.73 m² g⁻¹. X-ray photoelectron spectroscopy analysis showed that the M-LF-600 catalyst had the highest surface Fe³⁺/Fe²⁺ molar ratio and the best surface oxygen adsorption capacity. The CO oxidation of the LaFeO₃ catalyst demonstrated that the M-LF-600 catalyst had the best catalytic performance.