The influence of alkali metal cations in substituted nanostructured LaCoO3 on oxidation catalytic activity

Perovskite-type oxides La0.9M0.1CoO3 (M=K/Na/Li) were prepared by a citrate sol–gel method. These oxides were characterized by x-ray diffraction analysis (XRD), a scanning electron microscope (SEM) and the N2 physisorption Brunauer–Emmitt–Teller (BET) method. Their catalytic activity was studied by a constant microflow method for CO- and C3H6-oxidation and by thermal decomposition of diesel soot. The results show that the obtained perovskite materials have a sphere shape, particles size of about 40–50 nm and surface area from 12.0 to 14.9 m2 g−1. They have high catalytic activities decreasing in the sequence K > Na > Li on conversion CO, C3H6 and diesel soot. The total conversion temperature of CO, C3H6 and diesel soot is 325 °C, 340 °C and 430 °C, respectively. Thus, these catalysts have high applicability in the removal of exhaust gas, especially from diesel engines.