Effect of yttrium and manganese addition on catalytic soot combustion activity and anti-high-temperature stability of CeO2 catalyst

Abstract

In order to analyze the influence of the addition of yttrium and manganese on the soot combustion performance and high temperature stability of CeO2 catalyst, a series of Y/Mn-modified CeO2 catalysts were prepared. The effects of structural properties, textural properties, oxygen vacancies, Ce3+, surface adsorbed oxygen species, reduction properties and desorption properties of oxygen species on the activity were analyzed by various characterization methods. The results of the activity test show that the addition of manganese is beneficial to enhancement of the activity, while the addition of yttrium increases the amount of reactive oxygen species, but decreases the activity. After aging at 700 °C, the activity of the CeMn catalyst decreases most sharply, while the catalytic activity of the CeY catalyst can be maintained to a certain extent. Interestingly, the addition of yttrium and manganese at the same time can stabilize the activity. The fundamental reason is that yttrium and manganese move to the surface of the solid solution after aging, which increases the reduction performance of the catalyst, thus contributing to the increase of activity. Although the activity of CeYMn catalyst decreases after aging at 800 °C, it is still higher than that of other catalysts aged at 700 °C.