Investigation of LaCoO3, LaFeO3 and LaCo0.5Fe0.5O3 perovskites as catalyst precursors for syngas production by partial oxidation of methane

Abstract

The effect of substitution of cobalt by iron in LaCo1−xFexO3 (x = 0.0, 0.5 and 1.0) perovskite-type oxides on its physical properties and catalytic performance in the partial oxidation of methane (POM) reforming was investigated. The perovskites were characterized by X-Ray Diffraction (XRD) and the diffractograms were refined by the Rietveld method, X-Ray Fluorescence (XRF), Thermal analysis, BET (Brunauer-Emmett-Teller) specific area, Temperature Programmed Reduction (TPR) and Scanning Electron Microscopy (SEM). Remarkable is the product distribution varying with space time and with perovskite-type catalyst employed. For lower W/F values, the major product was H2 for the LaCoO3 (55.8%) and LaCo0.5Fe0.5O3 (59.2%), with similar ratios H2/CO (1.8–1.9) and low CO2 formation. On the other hand, the commercial catalyst (REF-11) was relatively more active (conversion of 75.2%), and the H2 production was 60.7%. Differently was the LaFeO3 perovskite that showed lower H2 and CO formation or ratio of H2/CO, but a significant increasing of CO2 formation. According to the catalytic and characterization results before and after reaction, we proposed reaction routes that showed different paths on the LaCoO3, LaFeO3 and mixed perovskite-type oxides.