Effect of the Precursor Solution Concentration and Modification Ions on the Catalytic Property of La-Hexaaluminate Catalysts

Abstract

Lanthanum hexaaluminates LaAl12O19-δ modified by transition-metal ion (Mn, Co and Ni ) were prepared through co-precipitation of metal nitrates within the water phase of a Triton X-100/n-hexanol/cyclohexane reverse microemulsion. The effects of different modification ion and the precursor solution concentration on the catalytic property of catalysts were investigated. The structure and properties of these samples were characterized by XRD, BET, SEM and TG-DTA. The stabilities of catalysts were assessed by measuring the activities for combustion of methane. Upon calcination at 1200°C, when the precursor solution concentration is 0.75M, the sample LaMnNiAl10O19-δ retained a specific surface area of 40.34m2/g and showed a excellent activity for methane combustion, which temperature at 10% , 90% and 99% conversion were 420 °C, 690 °C and 760 °C, respectively.