Lanthanum-Based Perovskite-Type Oxides La_1−<i>x</i>Ce_<i>x</i>BO₃(B = Mn and Co) as Catalysts: Synthesis and Characterization

Abstract

La 1− x Ce x CoO 3 (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mrow><mml:mi>x</mml:mi></mml:mrow></mml:math>= 0, 0.2, 0.4) and La 1− x Ce x MnO 3 (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:mrow><mml:mi>x</mml:mi></mml:mrow></mml:math>= 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 H 2 -TPR and catalytic performance. All synthesized samples showed well crystalline perovskite structure, 8–22 nm crystallite sizes, and SSA with 2–27 m 2 g −1 . The XRD results showed that the Ce substitution promoted the structural transformation for LaCoO 3 from rhombohedral into cubic and for LaMnO 3 no change in lattice geometry. Substitution with cerium (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M3"><mml:mrow><mml:mi>x</mml:mi></mml:mrow></mml:math>= 0.2) showed smaller crystallite size, higher SSA, and the highest reducibility and catalytic activity for LaCoO 3 .