Three-Dimensionally Ordered Macroporous La0.9ni0.5co0.5o3-Δ Perovskite Catalyst with Enhanced Catalytic Performance for Phenol Hydrodeoxygenation

Abstract

Three-dimensionally ordered macroporous (3DOM) La0.9Ni1-xCoxO3-δ (x=0, 0.1, 0.3, 0.5 and 0.7) perovskite oxides were prepared using monodisperse (polymethyl methacrylate) microspheres as templating agents through the sol-gel method. The crystal structure, morphology, elemental valence, and specific surface area of 3DOM La0.9Ni1-xCoxO3-δ were characterized by XRD, TEM, SEM, XPS, and H2-TPR. The results indicate that the 3DOM La0.9Ni1-xCoxO3-δ exhibits a stable perovskite structure. The doping of cobalt ions leads to the distortion of the BO6 (B= Co, Ni) octahedron and alters the mixed valence state of Ni, resulting in crystal structure distortion and formation of oxygen vacancies on the surface of the La0.9Ni1-xCoxO3-δ perovskite. More importantly, surface oxygen defect density is influenced by the amount of cobalt ion doping at the B site. Increasing the doping amount initially enhances the number of oxygen vacancies, but with a further increase in doping, the number of oxygen vacancies decreases. The ordered three-dimensional pore structure effectively reduces mass transfer resistance, thereby enhancing deoxygenation reaction activity and selectivity. The hydrodeoxygenation reaction of phenol primarily involves direct deoxygenation and partial isomerization and hydrogenation reactions occurring concurrently. At normal pressure and 350°C, the 3DOM La0.9Ni0.5Co0.5O3-δ catalyst achieves a single-pass conversion rate of 34.22% and a benzene selectivity of 94.92%.

Keywords: ：3DOM, Perovskite, hydrodeoxygenation, oxygen vacancies