Positive effects of the Sr doping on LaCoO3 perovskites for simultaneous catalytic oxidation performances of NO and Hg0

Abstract

LaCoO3 perovskite, with a general formula of ABO3, have received significant attention as environmental functional catalysts for NO and Hg0 oxidation owing to their compositional adjustability and chemical stability. Structural modifications of the perovskite have been performed through the substitution of La atoms at the A-site with atoms of different ion radii to enhance the oxidation ability. In this study, herein, a series of La1–xSrxCoO3 (x = 0.1–0.5) perovskites were synthesized, resulting in a transition from the R–3C rhombohedral phase structure to the Pm-3m cubic phase. Sr doping was effective in improving the oxidation of NO and Hg0. The improved catalytic activity was attributable to the generation of more electronegative Co3+ and the higher content of surface-adsorbed oxygen species. Moreover, Sr doping enhanced the redox performance and reduced the reaction temperature. Notably, SrCO3 species were the main factors responsible for the reducing the activation of La1–xSrxCoO3 (x = 0.1–0.5) perovskites, which could be detected when the Sr doping content exceeded 0.4. This study provides a screening strategic idea for the designing highly active perovskite catalysts.