Comparison of the nickel addition patterns on the catalytic performances of LaCoO3 for low-temperature CO oxidation

Abstract

Effect of nickel on the catalytic performances of LaCoO3 for CO oxidation is investigated, by partial substitution of Co with Ni atoms in the framework or by deposition of NiO on the surface of LaCoO3. Results show that the activity decreases in order of 10% Ni/LaCoO3>LaCoO3>LaCo0.8Ni0.2O3, with the CO ignition temperature of 60, 110 and 140°C, respectively (reaction conditions: 0.5% CO/Ar and 7.5% O2/Ar, balanced with Ar; space velocity of 30000mLg−1h−1). Based on the characterizations such as XPS, H2-TPR, O2-TPD and CV measurements, we inferred that the high activity of 10% Ni/LaCoO3 is attributed to a synergistic effect induced by NiO and LaCoO3, and the low activity of LaCo0.8Ni0.2O3 is to the enrichment of La atoms on the surface, caused by the Ni incorporation. Long-time stability test indicates that 10% Ni/LaCoO3 is stable in the reaction, with no appreciable loss of activity within 32h. The highly active and stable activity of 10% Ni/LaCoO3 suggests that impregnation of metal oxides on the surface of perovskite can be a feasible strategy for the preparation of industrial catalyst for CO oxidation.