Effect of oxide-ion conductivity of apatite-type Ln10Si6O27 on catalytic activity for toluene combustion
Effect of oxide-ion conductivity of apatite-type Ln10Si6O27 on catalytic activity for toluene combustion
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DOI：
10.1080/21870764.2021.1992850
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发表时间：
2021-10
影响因子：
2.3
通讯作者：
K. Matsuo;Naoyoshi Nunotani;N. Imanaka
中科院分区：
文献类型：
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作者：
K. Matsuo;Naoyoshi Nunotani;N. Imanaka
摘要采用具有氧化离子导电性的磷灰石型Ln10Si6O27 （Ln = La, Sm, Gd）固体，研究了导电性对1wt % Pt/Ln10Si6O27催化甲苯燃烧活性的影响。随着Ln3+离子尺寸的增大，Ln10Si6O27的晶格体积增大，导致电导率增强，这可能是由于氧化离子传导途径的扩展；即电导率的增大顺序为Gd10Si6O27 < Sm10Si6O27 < La10Si6O27。Ln10Si6O27促进剂的导电性影响了1wt % Pt/Ln10Si6O27的氧释放能力，导致Pt0氧化为Pt2+/4+。Pt/Ln10Si6O27催化剂有利于甲苯的燃烧，催化活性依次为：1 wt% Pt/Gd10Si6O27 < 1 wt% Pt/Sm10Si6O27 < 1 wt% Pt/La10Si6O27；这个顺序与表面积、铂分散或酸度不一致。这些结果表明，催化活性受Ln10Si6O27助剂电导率的影响。
ABSTRACT By using apatite-type Ln10Si6O27 (Ln = La, Sm, Gd) solids with oxide-ion-conduction properties, the effect of conductivity on the catalytic activity of 1 wt% Pt/Ln10Si6O27 for toluene combustion was clarified. With increasing Ln3+ ion size, the lattice volume of Ln10Si6O27 increased, resulting in the enhancement of the conductivity, likely due to the expansion of the oxide-ion-conducting pathway; that is, the conductivity increased in the order Gd10Si6O27 < Sm10Si6O27 < La10Si6O27. The conductivity of the Ln10Si6O27 promoter affected the oxygen release ability of 1 wt% Pt/Ln10Si6O27, which led to the oxidation of Pt0 to Pt2+/4+. Correspondingly, the Pt/Ln10Si6O27 catalyst facilitated toluene combustion, and the catalytic activity increased in the order 1 wt% Pt/Gd10Si6O27 < 1 wt% Pt/Sm10Si6O27 < 1 wt% Pt/La10Si6O27; this order was not consistent with the surface area, Pt dispersion, or acidity. These results indicate that the catalytic activity was affected by the conductivity of the Ln10Si6O27 promoter.