Total Oxidation of Methane and Chlorinated Hydrocarbons on Zirconia Supported A_1–xSr_xMnO₃ Catalysts

Abstract

The catalytic behavior of ZrO 2 and ZrO 2 containing 8 mol-% Y 2 O 3 supported A 1±x Sr x MnO 3 (A = La, didymium) perovskites was studied in the total oxidation of methane, chloromethane and dichloromethane considering catalyst deactivation and byproduct formation. The perovskites are dispersed on the support surface; clusters with a perovskite-like structure were formed. The supported catalysts are characterized by higher specific surface areas compared with the unsupported ones. Partial substitution of A-site cations by Sr leads to an enhancement of the catalytic activity in the total oxidation of methane, but not in the total oxidation of chlorinated hydrocarbons (CHC). The catalytic activity of supported and unsupported catalysts is comparable in the total oxidation of methane in spite of the significantly lower perovskite content of the supported catalysts. In the CHC conversion the catalytic activity of the supported catalysts is higher than that of the unsupported ones.

LaMnO3 Perovskite Supported Noble Metal Catalysts for the Total Oxidation of Methane

“…It is assumed that the noble metals are mainly incorporated in the perovskite lattice (e.g., LaMn 1-x Pd x O 3+d ), and thus, the region of reducible species is enhanced (see below). For the LaMnO 3+d sample, a small signal was observed above 300°C, which is assigned to the weakly bonded a-oxygen based on the nonstoichiometry and the defect structure of the perovskite [8]. Two peaks were detected above 600°C.…”

Synthesis and Characterization of Lamn1-XFexO3 (X=0, 0.1, 0.2) by Coprecipitation Route

“…The number of catalysts used in modern chemical industries are based on mixed oxide including perovskite oxide ABO 3 where A is a rare earth element, B is 3d transition metals remain predominant [6] perovskite oxides crystals can have broad applications in advanced technologies such as catalysts, oxide fuel cell, chemical sensors, magnetic materials, electrode materials [7][8][9]. Perovskites, especially LaMnO 3 , have also been used in environmental applications, e.g., the oxidation of hydrocarbons [10][11][12], chlorinated organics [13] and H 2 O 2 reactions [14]. LaMnO 3 shows good stability, flexible oxygen stoichiometry (δ) and the different Mn oxidation states i.e., Mn 2+ , Mn 3+ , Mn 4+ , which strongly affects the catalytic behavior.…”

CO and H2 oxidation over Pt/BaSnO3 catalysts

“…They attract great attention as catalysts for many oxidation processes, for example, total oxidation of hydrocarbons (methane, propane) [2,3], chlorinated hydrocarbons [4,5] and ammonia [6], being therefore proposed as an economical substitute for noble metal-based catalysts. They are also efficient catalysts for the oxidation of carbon monoxide [7][8][9].…”