La1-xSrxCoO3 (x=0, 0.2) Perovskites Type Catalyst for Carbon Monoxide Emission Control from Auto-Exhaust

Abstract

Abstract Perovskite type catalysts La 1-x Sr x CoO 3 (x=0, 0.2) composition prepared by co precipitation method which were tested for carbon monoxide (CO) oxidation. The prepared perovskite samples were characterized by X-ray diffraction (XRD), BET surface area, scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), temperature-programmed reduction by hydrogen (H 2 -TPR). XRD analysis showed that La 1-x Sr x CoO 3 (x=0, 0.2) are a single-phase perovskite type oxides. Traces of La 0.6 Sr 0.4 CoO 3 in addition to perovskite phase were detected in the La 0.8 Sr 0.2 CoO 3 catalyst. Specific surface area of perovskites were 2.60 m 2 g -1 and 5.31 m 2 g -1 for LaCoO 3 and La 0.8 Sr 0.2 CoO 3 respectively. The catalytic activity of the perovskite samples (for low-temperature CO oxidation) was measured using a stainless steel reactor with an inlet gas mixture containing 1% CO, 1% O2 and 98% N2. The perovskites catalysts showed good structural and chemical stability and high activity for the catalytic CO oxidation reaction. La 0.8 Sr 0.2 CoO 3 exhibited higher activity for CO conversion than LaCoO 3 . 100% CO oxidation at 268 °C was achieved with this catalyst. Strontium substitution in LaCoO 3 is responsible for enhanced CO oxidation activity due to easy reduction of transition metal and oxygen desorption properties.