Photochemical Synthesis and Catalytic Properties of Atomically Dispersed Palladium Catalyst

催化是自然界中普遍存在的重要现象，是化学学科中极为重要的研究方向。深刻理解催化反应的机制是有效设计催化剂和调控反应历程的重要基础。然而，作为最为重要的多相催化剂，负载型的纳米颗粒催化剂的结构复杂，传统的制备方法无法得到均一的反应活性中心。因此，在传统的多相催化体系中，催化的分子机制往往很难被深入理解。 单原子分散催化剂所有的活性中心均暴露在反应环境中且结构均一，使单原子分散催化剂具有优异的催化活性、选择性和特殊的催化能力，为催化机理研究提供了理想的模型体系。因此，单原子分散催化剂在近十年来越来越引起了人们的关注。但目前单原子分散催化剂研究领域仍存在两大问题。其一，活性组分的负载量较低，使催化...Catalysis is essential in nature and a central issue in chemistry. Understanding the molecular mechanism during catalytic process is the fundamental to design catalysts and manipulate reactions. However, for traditional heterogeneous catalysts based on supported nanoparticles, the complexity of the structure makes it impossible to study reaction mechanism on molecular level. As a new class of ca...学位：理学博士院系专业：化学化工学院_无机化学学号：2052012015349

A cationic surfactant assisted selective etching strategy to hollow mesoporous silica spheres

通讯作者地址: Zheng, NF (通讯作者), Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Coll Chem & Chem Engn, Xiamen 361005, Peoples R China 地址: 1. Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Coll Chem & Chem Engn, Xiamen 361005, Peoples R China 2. Xiamen Univ, Dept Chem, Coll Chem & Chem Engn, Xiamen 361005, Peoples R China 电子邮件地址: [email protected] mesoporous silica spheres have recently attracted increasing attention. However, effective synthesis of uniform hollow mesoporous spheres with controllable well-defined pore structures for fundamental research and practical applications has remained a significant challenge. In this work, a straightforward and effective "cationic surfactant assisted selective etching" synthetic strategy was developed for the preparation of high-quality hollow mesoporous silica spheres with either wormhole-like or oriented mesoporous shell. The as-prepared hollow mesoporous silica spheres have large surface area, high pore volume, and controllable structure parameters. Our experiments demonstrated that cationic surfactant plays critical roles in forming the hollow mesoporous structure. A formation mechanism involving the etching of solid SiO2 accelerated by cationic surfactant followed by the redeposition of dissolved silica species directed by cationic surfactant is proposed. Furthermore, the strategy can be extended as a general strategy to transform silica-coated composite materials into yolk-shell structures with either wormhole-like or oriented mesoporous shell.NSFC 21021061,20925103 ,20923004 ,20871100 MOST of China 2009CB930703,2011CB932403 Fok Ying Tung Education Foundation 121011 NSF of Fujian 2009J06005 Key Scientific Project of Fujian Province 2009HZ0002-

Hollow Mesoporous Aluminosilica Spheres with Perpendicular Pore Channels as Catalytic Nanoreactors

通讯作者地址: Zheng, NF (通讯作者),Xiamen Univ, Coll Chem & Chem Engn, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 地址: 1. Xiamen Univ, Coll Chem & Chem Engn, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 2. Xiamen Univ, Coll Chem & Chem Engn, Dept Chem, Xiamen 361005, Peoples R China 3. Univ Calif Santa Barbara, Dept Chem Engn, Santa Barbara, CA 93106 USA 电子邮件地址: [email protected] design and synthesis of hollow/yolk-shell mesoporous structures with catalytically active ordered mesoporous shells can infuse new vitality into the applications of these attractive structures. In this study, we report that hollow/yolk-shell structures with catalytically active ordered mesoporous aluminosilica shells can be easily prepared by using silica spheres as the silica precursors. By simply treating with a hot alkaline solution in the presence of sodium aluminate (NaAlO2) and cetyltrimethylammonium bromide (CTAB), solid silica spheres can be directly converted into high-quality hollow mesoporous aluminosilica spheres with perpendicular pore channels. On the basis of the proposed formation mechanism of etching followed by co-assembly, the synthesis strategy developed in this work can be extended as a general strategy to prepare ordered mesoporous yolk-shell structures with diverse compositions and morphologies simply by replacing solid silica spheres with silica-coated nanocomposites. The reduction of 4-nitrophenol with yolk-shell structured Au@ordered mesoporous aluminosilica as the catalyst has clearly demonstrated that the highly permeable perpendicular pore channels of mesoporous aluminosilica can effectively prevent the catalytically active yolk from aggregating. Furthermore, with accessible acidity, the yolk-shell structured ordered mesoporous aluminosilica spheres containing Pd yolk exhibit high catalytic activity and recyclability In a one-pot two-step synthesis involving an acid catalysis and subsequent catalytic hydrogenation for desired benzimidazole derivative, which makes the proposed hollow ordered aluminosilica spheres a versatile and practicable scaffold for advanced catalytic nanoreactor systems.MOST of China 2011CB932403 2009CB930703 NSFC 21131005 21021061 20925103 Fok Ying Tung Education Foundation 121011 NSF of Fujian Province 2009J06005 U.S. National Science Foundation CHE-092465

An iron silicate based pH-sensitive drug delivery system utilizing coordination bonding

E-mail Addresses: [email protected] we report a drug delivery system based on hollow iron silicate nanospheres. Fe3+ on the nanospheres' surface can effectively bind with doxorubicin (DOX), an anticancer drug, through coordination bonds. The bonds are fairly stable in a neutral environment but could easily break up in an acid environment. The release of DOX from hollow iron silicate nanospheres into cancer cells can be therefore triggered by a pH drop caused by endocytosis. The iron silicate shell allows a DOX loading content of up to 50.2% in weight, which is significantly higher than most drug delivery systems reported. Cell experiments show that DOX-loaded hollow iron silicate nanospheres exhibit a higher efficiency in killing cancer cells than free DOX, and a higher cytotoxicity for human hepatoma cells than hepatocyte cells at the same DOX-loaded nanospheres' concentration. Confocal laser scanning microscopy (CLSM) experiments show the releasing and transportation process of DOX, and confirm the enrichment of DOX in cell nuclei.MOST of China 2011CB932403 NSFC 21131005 21021061 20925103 Fok Ying Tung Education Foundation 12101

Photochemical route for synthesizing atomically dispersed palladium catalysts

该工作由校内外多个课题组共同努力，历时三年多完成。我校郑南峰、傅钢等课题组紧密协作负责催化剂的合成、表征、催化测试及机理研究；中科院物理研究所谷林研究员主要负责催化剂的球差校正透射电子显微研究；加拿大达尔豪斯大学的张鹏课题组参与催化剂的同步辐射X-射线吸收谱研究。该研究工作的第一、二作者刘朋昕、赵云均为我校博士生。【Abstract】Atomically dispersed noble metal catalysts often exhibit high catalytic performances, but the metal loading density must be kept low (usually below 0.5%) to avoid the formation of metal nanoparticles through sintering. We report a photochemical strategy to fabricate a stable atomically dispersed palladium–titanium oxide catalyst (Pd 1 /TiO2 ) on ethylene glycolate (EG)–stabilized ultrathin TiO2 nanosheets containing Pd up to 1.5%.The Pd 1 /TiO2 catalyst exhibited high catalytic activity in hydrogenation of C=C bonds, exceeding that of surface Pd atoms on commercial Pd catalysts by a factor of 9.No decay in the activity was observed for 20 cycles. More important, the Pd 1 /TiO2 -EG system could activate H2 in a heterolytic pathway, leading to a catalytic enhancement in hydrogenation of aldehydes by a factor of more than 55.Supported by Ministry of Science and Technology of China grant 2015CB932303; National Natural Science Foundation of China grants 21420102001, 21131005, 21390390, 21133004, 21373167, 21573178, and 21333008; a NSERC CGS Alexander Graham Bell scholarship (D.M.C.); and a NSERC Discovery grant (P.Z.)

光化学法制备基于(001)面暴露的锐钛矿和商用P25二氧化钛的单原子分散钯催化剂（英文）

单原子分散催化剂由于其独特的结构和性质,在催化研究中已展现出巨大的潜力,成为了催化研究的前沿领域.传统的催化剂制备方法（例如共沉积,浸渍法等）在单原子分散催化剂的制备中卓有成效,但不断涌现的新方法能够制备出传统方法不能制备的新型单原子分散催化剂.最近,光化学方法由于其步骤简单和制备条件温和的优点而引起了广泛关注.在之前的研究中我们揭示了光化学法制备单原子分散催化剂的分子机制.我们发现,紫外光照的作用在于将二氧化钛纳米片表面的乙二醇基激发生成乙二醇自由基,后者不仅有利于氯钯酸根中氯离子的脱除,还可通过Pd–O键将钯原子锚定在载体上,形成了独特的"钯-乙二醇-二氧化钛"的界面.根据对光化学法制备技术的理解,本文将光化学法拓展到其他二氧化钛体系,成功制备了基于（001）面暴露的锐钛矿纳米晶和商用二氧化钛P25的单原子分散钯催化剂.通过吸附和紫外光照,可以在室温下简单地制备单原子分散钯催化剂.扩展X射线吸收精细结构实验表明,紫外光照的作用是促进钯原子上氯离子的离去和更多Pd–O键的形成.与通过其它方法制备的催化剂相比,光化学法制备的两种Pd/TiO催化剂在苯乙烯的催化氢化反应中表现出更高的活性和稳定性.转化频率TOF为商用Pd/C催化剂的6倍.单原子分散催化剂为研究催化反应中复杂的界面效应提供了理想的模型体系.由于CO的催化氧化反应性能对金属活性中心的化学配位环境高度敏感,因此我们选择它作为模型反应以研究光化学法制备的单原子分散催化剂之间的差异.结果发现,两种载体制备的单原子分散钯催化剂都具有很好的催化CO氧化低温活性,373 K时CO转化率均可高达96%.其中,负载在（001）面暴露的锐钛矿纳米晶的催化剂在343 K时TOF高达6.7×10s,比有文献报道的活性最高的Pd/La-修饰AlO催化剂在相同条件下高3.3倍,是目前Pd基催化剂在催化CO氧化反应中的活性最佳记录.这可能是由于二氧化钛的载体效应引起的.虽然两种催化剂的催化活性相当,但Pd/P25的表观活化能比Pd/TiO（NC）高一倍左右.两种催化剂的金属都以单原子态分布,催化CO氧化反应的机制却可能完全不同.这说明单原子分散催化剂的性能与载体的表面性质密切相关.本文为单原子催化中载体的选择和原子尺度的界面调控提供了新的研究思路.supported by the Ministry of Science and Technology of nano major research projects(2015CB932303)；the National Natural Science Foundation of China(21420102001,21131005,21333008,21390390)~~

仿C60分子结构的减振防护结构

本实用新型属于减振防护结构和仿生领域，具体地说是一种仿C60分子结构的减振防护结构，球壳的外部均匀分布了六十个四孔弹性球，每个四孔弹性球上均开设有四个孔，其中一个孔通过弹簧套筒与球壳连接，另外三个孔均通过连接杆与相邻的三个四孔弹性球相连；弹簧套筒包括活塞、套筒、减振弹簧及限位螺栓，限位螺栓的一端与球壳螺纹连接，另一端与套筒的一端螺纹连接，套筒的另一端通过活塞与四孔弹性球上开设的孔相连，套筒内容置有减振弹簧，减振弹簧的两端分别与限位螺栓的另一端及活塞抵接，通过减振弹簧的压缩/复位实现减振防护。本实用新型结构简单、可靠，操作方便，能够更有效地对球形机器人、精密元件设备等进行全方位振动冲击防护。</p

灵境卫士：基于ACP的网络安全平行监管研究

网络安全起源于计算机网络的理论测试，而随着信息与通信技术的发展，网络安全风险呈现出来源广（volume）、方式多（variety）、过程隐（visibility）与损失高（value）的“4V”特性，与之相伴的是网络空间形态与复杂度的双重变化。近期兴起的元宇宙风潮，使以人为中心构建出的网络空间拥有映射出真实世界的能力，也将真实世界暴露在网络安全风险之下。然而，网络安全监管没有跟上网络空间的变化，仍然在网络空间中寻求解决之道。介绍了一种网络安全平行监管系统——灵境卫士，它基于人工系统、计算实验与平行执行的ACP方法搭建，从信息-物理-社会系统（cyber-physical-social systems，CPSS）的视角改善当前网络安全监管的窘境。展示了灵境卫士在电信反诈骗与工业物联网场景下的应用方案，为其在不同领域的网络安全监管工作提供启发与借鉴

RETGEM探测器的初步测试

研制了一种新型的带有阻抗性电极的TGEM——RETGEM(Thick GEM with Resistive Electrodes)探测器,阻抗性电极可以有效地保护探测器和前端电子学免于偶尔放电的损伤。对RETGEM探测器进行了初步测试,其中包括计数率、能量分辨、增益以及打火率。结果表明,探测器达到了设计的基本要求