Bai Xue, Chen Bo, Yang Fei, Liu Xianping, Silva-Nunes Daniel, Robinson Ian
School of Materials Science and Engineering, Tongji University Shanghai 201804 China
London Centre for Nanotechnology, University College London London WC1H0AH UK
RSC Adv. 2018 Oct 1;8(59):33631-33636. doi: 10.1039/c8ra05918g. eCollection 2018 Sep 28.
SAPO-34 is widely used as a catalyst for important industrial reactions, such as the methanol-to-olefin (MTO) reaction and selective catalytic reduction (SCR) of nitrogen oxides (NO ). The internal structure of SAPO-34 has a great influence on the catalytic performance. Two-dimensional (2D) images of the SAPO-34 particle surfaces from scanning electron microscopy (SEM) show clearly well-faceted cube morphologies, which suggest they should be quite uniform perfect crystals. However, Bragg coherent X-ray diffraction imaging (BCDI) of the SAPO-34 particles shows a rich internal structure existing within these crystals. In this work, we investigated the internal structure of a SAPO-34 zeolite by serial block-face scanning electron microscopy (SBFSEM). The internal structure observed in the backscattered electron (BSE) micrographs from SBFSEM and the energy dispersive spectroscopy (EDS) measurements is found to be consistent with the BCDI results. From the three-dimensional (3D) structural images of SAPO-34 crystals obtained by SBFSEM, the domains within the individual SAPO-34 were visualized and quantified.
SAPO-34被广泛用作重要工业反应的催化剂，如甲醇制烯烃（MTO）反应和氮氧化物（NO ）的选择性催化还原（SCR）。SAPO-34的内部结构对催化性能有很大影响。扫描电子显微镜（SEM）得到的SAPO-34颗粒表面的二维（2D）图像清晰地显示出多面体立方形态，这表明它们应该是相当均匀的完美晶体。然而，SAPO-34颗粒的布拉格相干X射线衍射成像（BCDI）显示这些晶体内部存在丰富的内部结构。在这项工作中，我们通过连续块面扫描电子显微镜（SBFSEM）研究了SAPO-34沸石的内部结构。发现从SBFSEM的背散射电子（BSE）显微照片和能量色散光谱（EDS）测量中观察到的内部结构与BCDI结果一致。从通过SBFSEM获得的SAPO-34晶体的三维（3D）结构图像中，可以对单个SAPO-34内的区域进行可视化和量化。
