Effect of Jahn−Teller Distortion in La_0.5Sr_0.5MnO₃ Cubes and Nanoparticles on the Catalytic Oxidation of CO and CH₄

Abstract

La 0.5 Sr 0.5 MnO 3 cube and nanoparticle catalysts were synthesized by the hydrothermal and coprecipitation method, respectively. The catalytic performances for CO and CH 4 oxidation were evaluated, and the effect of Jahn-Teller distortion on the catalytic performance was elucidated. La 0.5 Sr 0.5 MnO 3 nanoparticle catalyst showed a higher activity than the cube catalyst for CO oxidation at a lower temperature. While the catalytic activity of the cubes significantly increased at higher temperature, the complete conversion temperatures for CO were both the same at 210 °C. The trend for CH 4 oxidation activity was similar to the trend observed for CO oxidation activity. The catalytic mechanism of CO oxidation over La 0.5 Sr 0.5 MnO 3 cubes is proposed that the adsorbed CO was oxidized by the lattice oxygen. Then, the chemisorbed oxygen over La 0.5 Sr 0.5 MnO 3 cubes was transformed into the lattice oxygen by MnO 6 octahedra to reinforce the consumed lattice oxygen. The catalytic performances of La 0.5 Sr 0.5 MnO 3 cubes and nanoparticles were mainly predominated by Jahn-Teller distortion of the catalysts.

Three-dimensionally ordered macroporous La0.6Sr0.4MnO3 with high surface areas: Active catalysts for the combustion of methane

“…Areal rate (lmol/(cm 2 s)) k (Â10 À2 s À1 )/r (Â10 À3 lmol/(g s)) a (T 50% = 566°C and T 90% = 661°C) over our 3DOM LSMO-DP3 catalyst was much better than those (T 50% = 654°C and T 90% = 800°C) over La 0.9 Cu 0.1-MnO 3 [42], (T 50% = 710°C andT 90% = 770°C) over 20 wt% LaMnO 3 / MgO [43], (T 50% = 620°C and T 90% = 710°C) over La 0.5 Sr 0.5 MnO 3 [6], and (T 50% = 662°C and T 90% = 739°C) over La 2 CuO 4 nanorods [44], but inferior to those (T 50% = 365°C and T 90% = 425°C) over 1 wt% Pd/ZrO 2 [45] and (T 50% = 520°C and T 90% = 570°C) over La 0.5 Sr 0.5 MnO 3 cubes [46].…”

Experimental and DFT studies on Sr-doped LaMnO3 catalysts for NOx storage and reduction

“…4). 29,30 Therefore, the results above are only applicable for the DFT modeling. Mn-ter surfaces have a higher oxygen storage/release capacity, thereby increasing the oxidation activity during the reaction process.…”

Engineering the surface of perovskite La0.5Sr0.5MnO3 for catalytic activity of CO oxidation

“…The production of Mn 4+ at relatively high temperatures is important for the improvement of CO oxidation. 19,20 The catalytic CO oxidation over the as-obtained samples was evaluated in a CO-O 2 -N 2 stream. As shown in Fig.…”