Li Xiazhang, Huang Zuo-Gang, Zhang Haiguang, Zhang Yuying, Zhang Chunyan, Li Hui-Yin H, Martin David C, Ni Chaoying
Advanced Catalysis and Green Manufacturing Collaborative Innovation Center, Changzhou University, Changzhou 213164, People's Republic of China. Department of Materials Science and Engineering, University of Delaware, Newark, DE 19716, United States of America.
Nanotechnology. 2020 Aug 28;31(35):355704. doi: 10.1088/1361-6528/ab9473. Epub 2020 May 19.
Atomic-scale catalysts leverage the advantages of both heterogeneous catalysts for their stability and reusability and homogeneous catalysts for their isolated active sites. Here, a palladium catalyst supported by Si-thiol, a commercially available mercaptopropyl-modified and TMS-passivated amorphous silica, was synthesized and characterized by SEM,TEM, aberration-corrected STEM-HAADF, XRD, FT-IR and XPS. Statistical analysis revealed that the catalytic Pd species predominantly consisted of intermediate sized nanoparticles (<2 nm), small amounts of essentially isolated atoms (ca. 0.1 nm), and limited amounts of somewhat larger nanoparticles (<5 nm). The nanoscale atomic clusters dominated the reactivity and served as the key active sites for Suzuki coupling. The outcomes of the reaction were greatly affected by the choice of solvents, and Pd/Si-thiol was demonstrated to be reusable for more than three times without a noticeable loss of catalytic activity. [Formula: see text].
原子尺度催化剂兼具多相催化剂的稳定性和可重复使用性以及均相催化剂的孤立活性位点的优势。在此，合成了一种由硅硫醇负载的钯催化剂，硅硫醇是一种市售的巯丙基改性且经TMS钝化的无定形二氧化硅，并通过扫描电子显微镜（SEM）、透射电子显微镜（TEM）、像差校正扫描透射电子显微镜高角度环形暗场成像（STEM-HAADF）、X射线衍射（XRD）、傅里叶变换红外光谱（FT-IR）和X射线光电子能谱（XPS）对其进行了表征。统计分析表明，催化钯物种主要由中等尺寸的纳米颗粒（<2纳米）、少量基本孤立的原子（约0.1纳米）和有限数量的稍大纳米颗粒（<5纳米）组成。纳米级原子簇主导了反应活性，并作为铃木耦合反应的关键活性位点。反应结果受溶剂选择的影响很大，并且已证明Pd/Si-硫醇可重复使用三次以上而催化活性无明显损失。[公式：见正文]
