Facile synthesis of porous spherical La0.8Sr0.2Mn1−xCuxO3 (0 ≤ x ≤ 0.4) and nanocubic La0.8Sr0.2MnO3 with high catalytic activity for CO

Abstract

A molten salt method has been used to prepare porous La_0.8Sr_0.2Mn_1−xCu_xO₃ (0 ≤ x ≤ 0.4) (LSMC-X) microspheres and La_0.8Sr_0.2MnO₃ (LSM) nanocubes using spherical and cubic MnCO₃ as templates, respectively. XRD patterns showed a single perovskite phase when the Cu content was less than x = 0.3. SEM and TEM images indicated that the porous microspheres comprised many aggregated nanoparticles, while the nanocubes were solid with a smooth surface. LSM and LSMC-0 samples both possessed high surface areas (63.5045 and 49.6504 m² g⁻¹, respectively). Furthermore, the CO conversions showed that LSMC-0.2 had the best catalytic activity (T₅₀ = 83.63 °C, T₉₀ = 97.40 °C) and good stability. XPS analysis confirmed that Cu²⁺ doping induced Mn⁴⁺ formation and slight changes in the oxygen species, leading to different catalytic activity. Owing to their facile synthesis and high catalytic performance, we propose that these porous spherical La_0.8Sr_0.2Mn_1−xCu_xO₃ (0 ≤ x ≤ 0.4) and nanocubic La_0.8Sr_0.2MnO₃ catalysts are promising candidates for CO oxidation.