XRD characterization of highly dispersed metal catalysts on carbon support
XRD characterization of highly dispersed metal catalysts on carbon support
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碳载体上高度分散金属催化剂的 XRD 表征
DOI：
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发表时间：
1993
期刊：
影响因子：
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通讯作者：
P. Antonucci
中科院分区：
文献类型：
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作者：
P. Scardi;P. Antonucci
以H_2PtCl_6或K_2PtCl_6水溶液为原料制备了碳载Pt催化剂。通过X射线衍射（XRD）、透射电子显微镜（TEM）和循环伏安法（CV）研究了多次热活化处理后的颗粒尺寸和结构，并对三种技术的结果进行了比较。由于催化剂高度分散在非晶态载体上，用于确定微晶尺寸的常规 XRD 谱分析无法正确进行，因为与非晶相晕圈叠加的宽 Pt 峰之间存在强烈重叠。因此，基于 Rietveld 方法的全 XRD 图案拟合新程序被用来获得 Pt 颗粒尺寸（表面积）和晶格参数的可靠数据。所有结构和微观结构参数都在同一程序中进行了细化，同时还考虑了碳负载催化剂的透明度并最大限度地减少了无定形背景的影响。该方法还可以考虑双峰粒径分布的存在，而这是通过 CV 或 TEM 难以研究的。
Carbon-supported Pt catalysts were prepared from H_2PtCl_6 or K_2PtCl_6 aqueous solutions. Particle size and structure after several thermal activation treatments were studied by X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM), and Cyclic Voltammetry (CV), and the results of the three techniques were compared. As the catalysts were highly dispersed on an amorphous support, a conventional XRD profile analysis for crystallite size determination could not be performed properly, because of the strong overlapping between the broad Pt peaks superposed to the halos of the amorphous phase. Thus, a new procedure of whole XRD pattern fitting, based on the Rietveld method, was used to have reliable data of Pt particle size (surface area) and lattice parameter. All structural and microstructural parameters were refined within the same procedure, also considering the transparency of the carbon supported catalysts and minimizing the effect of the amorphous background. The method can also take into account the presence of bimodal particle size distributions, which is difficult to study by CV or TEM.