Lanthanum-Based Perovskite-Type Oxides La_1−xCe_xBO₃(B = Mn and Co) as Catalysts: Synthesis and Characterization

Abstract

La1−xCexCoO3(x= 0, 0.2, 0.4) and La1−xCexMnO3(x= 0, 0.2) perovskite-type oxides were prepared by sol-gel process. Characterization techniques EDS, FTIR, XRD, BET, and XPS experiments were performed to survey the composition, bulk structure, and the surface properties of perovskites. The reduction behavior, thermal stability, and catalytic activity were studied by H2-TPR and catalytic performance. All synthesized samples showed well crystalline perovskite structure, 8–22 nm crystallite sizes, and SSA with 2–27 m2 g−1. The XRD results showed that the Ce substitution promoted the structural transformation for LaCoO3from rhombohedral into cubic and for LaMnO3no change in lattice geometry. Substitution with cerium (x= 0.2) showed smaller crystallite size, higher SSA, and the highest reducibility and catalytic activity for LaCoO3.

Corrosion of Al85Ni9Ce6 amorphous alloy in the first hours of immersion in 3.5‐wt% NaCl solution: The role of surface chemistry

“…The presence of Ce 4+ is associated with an additional spin‐orbit splitting, showing six peaks designated as v‐u, v″‐u″ and v‴‐u‴. The u‴ (at approximately 916 eV) peak is considered as a fingerprint for Ce 4+ , being a direct indication of its presence on the surface subjected to XPS analysis in the Ce3d region. In this respect, its absence indicates that Ce 4+ is not found in the as‐spun surface.…”

The electrical modulus and other dielectric properties by the impedance spectroscopy of LaCrO3and LaCr0.90Ir0.10O3perovskites

“…[1][2][3][4][5][6][7] Additionally, the exibility in the chemical composition of these materials offers excellent possibilities in terms of control of their structures via substitution of a number of transition metals into the A or B cation sites. [8][9][10][11][12] Such properties make perovskite oxides very promising for several applications. The potential applications of these materials include ferroelectric random access memory, multilayer ceramic capacitors, magnetic eld sensors, solid oxide fuel cells (SOFCs), membranes, catalytic converters [13][14][15][16][17][18][19][20] etc.…”

Investigation of Thermal, Structural and Electrical Properties of LaMnO<sub>3</sub>-Sigma

“…This result is in good agreement with lower lattice parameters and unit cell volume calculated from the XRD patterns. On the other hand, peaks observed at around 1629.8 and 2365.6 cm −1 are attributed to the deformation mode of absorbed molecular water of the carrier KBr (H 2 O)n and CO 2 , respectively [12]. Since the number of absorption peaks is related to the number of vibrational freedom of the molecule.…”