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应用电化学去合金法制备了表面覆盖有Pt(Pd)原子层的Pt(Pd)-Cu合金催化剂.研究该催化剂在0.1mol.L-1HClO4酸性溶液中对氧气电化学还原的催化活性,并采用同步辐射反常X-射线衍射法(Anomalous X-ray Diffraction,AXRD)和表面X-射线散射法(Surface X-ray Scattering,SXS)从原子尺度研究了去合金化后催化剂的结构.分析对比纳米颗粒、薄膜和单晶3种不同形式的去合金化Pt-Cu的结构和催化活性以及Pt-Cu和Pd-Cu两种不同合金薄膜的结构和催化活性.结果表明,表面应力是影响催化剂催化活性的关键因素,而应力大小则与去合金化后所形成的表面Pt(Pd)层的厚度相关,材料尺寸和组成元素等都影响表面Pt(Pd)层的厚度.提出可利用调控材料表面的应力来设计高催化活性的催化剂.
Pt (Pd) -Cu alloy with Pt (Pd) atomic layer on the surface was prepared by electrochemical desalination.The catalytic activity of the catalyst for electrochemical reduction of oxygen in 0.1mol.L-1HClO4 acid solution The structure of de-alloying catalyst was investigated from atomic scale using Anomalous X-ray Diffraction (AXRD) and Surface X-ray Scattering (SXS) The structure and catalytic activity of three different types of de-alloyed Pt-Cu particles, films, films and single crystals, as well as the structure and catalytic activity of Pt-Cu and Pd-Cu alloy films were studied.The results show that the surface stress is the effect of catalyst catalysis But the size of the stress is related to the thickness of the Pt (Pd) layer formed by de-alloying, and the size and composition of the material affect the thickness of the Pt layer. It is proposed that the surface of the controllable material Of the stress to design high catalytic activity of the catalyst.