电镜三维重构技术量化Pt/mSiO2催化颗粒的空间分布

电镜三维重构技术量化Pt/mSiO₂催化颗粒的空间分布

王  戊，何佳清^*

（南方科技大学 物理系，广东 深圳  518055）

摘  要 负载型催化剂中纳米颗粒的空间分布对催化剂的活性、选择性和稳定性都有着重要的影响。精确测定催化颗粒在载体上，尤其是内外表面皆可负载颗粒的多孔载体上的空间分布，是当前的研究重点。本文采用透射电镜三维重构技术研究Pt纳米颗粒在多级孔二氧化硅微球（mSiO₂）载体上的空间分布情况。通过图像处理和关键结构的分割与提取，开展Pt/mSiO₂催化剂三维结构的定量分析，测定Pt颗粒的密度，并统计颗粒与第一和第二近邻颗粒之间的距离。通过空间极坐标系进一步评估颗粒的分布，发现Pt/mSiO₂催化颗粒的空间分布呈现非均匀性。基于三维空间球体的径向分析方法，量化Pt颗粒从mSiO₂载体内部到边缘不同区域的局部分布情况，且发现Pt颗粒在不同尺寸的mSiO₂载体上具有相似的空间分布规律。

关键词  透射电镜；三维重构技术；多孔载体催化剂；空间分布

中图分类号：TG115.21⁺5.3；O643.36；TF833 文献标识码：A   doi:10.3969/j.issn.1000-6281.2022.06.003

Quantifying the spatial distribution of Pt/mSiO₂ Catalyst by electron tomography

WANG Wu，HE Jia-qing^*

(Department of Physics, Southern University of Science and Technology, Shenzhen Guangdong 518055, China)

Abstract   The spatial distribution of nanoparticles (NPs) could effectively affect the activity, selectivity and stability of supported catalysts. The priority of current research is to accurately determine the spatial distribution of catalytic particles on the support, especially on the porous support with particles dispersed on both its inner and outer surfaces. In this work, electron tomography has been applied to investigate the spatial distribution of Pt NPs on porous silica microsphere (mSiO₂). It has been quantified the three-dimensional (3D) structure of Pt/mSiO₂ catalysts by image processing, segmentation and the extraction of key features. It has been achieved the measurement on the density of Pt NPs, and the distance between particles and nearest/second-nearest neighboring particles. Moreover, the particles in the Pt/mSiO₂ catalyst evaluated by the spatial polar coordinate system show that the spatial distribution of particles is non-uniform in the Pt/mSiO₂ catalyst. The radial analysis method derived from the 3D space sphere further quantifies the local distribution of Pt particles within different regions from inside to outside of mSiO₂, which indicates a similar spatial distribution of Pt particles on mSiO₂ with different sizes.

Keywords   transmission electron microscopy; electron tomography; porous supported catalysts; spatial distribution

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