Active Oxygen Species in Lan+1NinO3n+1 Layered Perovskites for Catalytic Oxidation of Toluene and Methane

Layered perovskites possess frameworks that can sustain a larger extent of oxygen nonstoichiometry than perovskites, which makes them possibly more suitable for catalytic applications. However, there is little work in literature concerning the catalytic behaviors of them. In this paper, La n +1 Ni n O 3 n +1 layered perovskites were selected as potential catalysts for catalytic oxidation of toluene and methane. The activation and transmission of active oxygen species over the layered structure were explored by using a range of analytical techniques, e.g., O 2 -TPD, XPS, and H 2 -TPR. It was noted that the LaNiO 3 ( n = ∞) that possessed the most chemisorbed oxygen species had the lowest activation energy ( E a, ca. 70.1 kJ mol –1 ) in toluene oxidation and the La 4 Ni 3 O 10 ( n = 3) that owned a superior lattice oxygen mobility showed the lowest E a (ca. 111.0 kJ mol –1 ) in methane oxidation. The La 2 NiO 4 ( n = 1) that lacked chemisorbed and superficial lattice oxygen species yielded the highest E a in either toluene or methane oxidation. It is expected that the work conduct herein could generate more awareness onto the potential catalyst application for layered perovskites and would also give promising insights into the correlation between structural framework and catalytic behaviors for extraordinary materials.