Abstract:

La_0.8Sr_0.2Mn_1-xCu_xO₃ (x=0,0.1,0.2,0.3,0.4) perovskite catalysts with Sr²⁺ and Cu²⁺ substituted at A and B sites were prepared by flame spray synthesis method for CO catalytic oxidation, and the effects of water vapor and CO₂ on the CO oxidation activity of the catalysts were investigated. The structure and catalytic activity of La_0.8Sr_0.2Mn_1-xCu_xO₃ catalysts were characterized and analyzed by XRD, SEM, EDS, BET, XPS, H₂-TPR and O₂-TPD. The catalysts prepared by flame spray synthesis exhibit good perovskite phases, loose porous structure and catalytic oxidation activity. La_0.8Sr_0.2Mn_0.9Cu_0.1O₃ achieves 50% CO and 90% CO conversion at 119.4℃ and 133.3℃, respectively. The doping of water vapor and CO₂ will form competitive adsorption with CO on the surface of the perovskite, resulting in the performance degradation of the five catalysts. And La_0.8Sr_0.2Mn_0.9Cu_0.1O₃ can achieve 90% CO conversion at 150.2℃. In the continuous stable catalytic oxidation test, the catalytic activity decreased less than 10%. Combined with the above CO catalytic oxidation experiment, the catalyst prepared by the flame spray synthesis method has good stability and catalytic activity, and is suitable for preparing a perovskite catalyst with high CO catalytic oxidation activity.

Key words: perovskite catalyst, flame spray synthesis, carbon monoxide, waste treatment, catalysis

摘要：

采用火焰喷雾合成法制备了Sr²⁺、Cu²⁺分别取代A、B位的La_0.8Sr_0.2Mn_1-xCu_xO₃ （x=0，0.1，0.2，0.3，0.4）钙钛矿催化剂，并用于CO催化氧化实验，研究了水蒸气和CO₂对催化剂CO氧化活性的影响。对不同取代量La_0.8Sr_0.2Mn_1-xCu_xO₃ 催化剂进行了XRD、SEM、EDS、BET、XPS、H₂-TPR和O₂-TPD等表征测试。结果表明，火焰喷雾合成法制备的钙钛矿催化剂具有良好的钙钛矿相、疏松多孔结构和催化氧化活性。其中，La_0.8Sr_0.2Mn_0.9Cu_0.1O₃分别在119.4℃和133.3℃实现50%和90%的CO转化率。掺杂水蒸气和CO₂会与CO在催化剂表面形成竞争吸附，导致5种催化剂性能衰减，但La_0.8Sr_0.2Mn_0.9Cu_0.1O₃仍能在150.2℃实现90%的CO催化转化，在连续稳定性催化氧化测试中，5种催化剂性能衰减不超过10%。结合上述CO催化氧化实验，火焰喷雾合成法制备的催化剂具有良好的稳定性和催化活性，适合制备高CO催化氧化活性的钙钛矿催化剂。

关键词: 钙钛矿催化剂, 火焰喷雾法合成, 一氧化碳, 废物处理, 催化