Role of the Three-Phase Boundary of the Platinum-Support Interface in Catalysis: A Model Catalyst Kinetic Study.
Role of the Three-Phase Boundary of the Platinum-Support Interface in Catalysis: A Model Catalyst Kinetic Study.
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铂 - 支持界面的三相边界在催化中的作用：模型催化剂动力学研究。
DOI：
10.1021/acscatal.6b00829
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发表时间：
2016-09-02
期刊：
影响因子：
12.9
通讯作者：
Metcalfe, Ian S.
中科院分区：
文献类型：
--
作者：
Papaioannou, Evangelos I.;Bachmann, Christoph;Neumeier, Jonas J.;Frankel, Daniel;Over, Herbert;Janek, Juergen;Metcalfe, Ian S.
采用脉冲激光沉积和离子束刻蚀的方法制备了一系列微结构的负载型铂催化剂薄膜(负载在氧化钇稳定的氧化锆上)和合适的铂催化剂参照系(负载在单晶氧化铝上)。该薄膜的三相界面的面积比长度(铂、载体和气相之间的三相界面长度除以样品的表面积)在4个数量级上变化，从4.5×10~2到4.9×106m~(-2)，相当于0.2μm到约9000μm的结构长度尺度。当铂被负载在氧化钇稳定的氧化锆上时，反应速率明显地取决于三相边界的特定区域长度L(TPB)。当铂负载在氧化铝上时，没有观察到类似的关系。我们认为，三相界面的存在为铂提供了一个额外的供氧通道，这是通过在氧化钇稳定的氧化锆载体内或之上的扩散以及铂上的表面扩散来实现的。
A series of microstructured, supported platinum (Pt) catalyst films (supported on single-crystal yttria-stabilized zirconia) and an appropriate Pt catalyst reference system (supported on single-crystal alumina) were fabricated using pulsed laser deposition and ion-beam etching. The thin films exhibit area-specific lengths of the three-phase boundary (length of three-phase boundary between the Pt, support, and gas phase divided by the superficial area of the sample) that vary over 4 orders of magnitude from 4.5 × 102 to 4.9 × 106 m m–2, equivalent to structural length scales of 0.2 μm to approximately 9000 μm. The catalyst films have been characterized using X-ray diffraction, atomic force microscopy, high-resolution scanning electron microscopy, and catalytic activity tests employing the carbon monoxide oxidation reaction. When Pt is supported on yttria-stabilized zirconia, the reaction rate clearly depends upon the area-specific length of the three-phase boundary, l(tpb). A similar relationship is not observed when Pt is supported on alumina. We suggest that the presence of the three-phase boundary provides an extra channel of oxygen supply to the Pt through diffusion in or on the yttria-stabilized zirconia support coupled with surface diffusion across the Pt.
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