Electrochemical continuous production of supported metal nanocatalysts with high-density step atoms and high activity

铂族金属是催化、能源、石油化工等领域广泛应用的催化剂。由于铂族金属储量稀少，价格昂贵，如何提高其催化活性、稳定性和利用效率一直是上述领域中的重大关键问题。提高铂金属纳米催化剂的活性和利用率的途径之一是减小催化剂的粒径，并尽可能分散地负载到载体表面。目前，商品碳载铂（Pt/C）催化剂中Pt粒子的尺寸为3nm左右，已基本趋于最优化的尺寸。我们课题组于2007年用电化学方法首次制备出Pt二十四面体纳米晶，开辟了一条调控纳米粒子的表面结构显著提升金属纳米催化剂性能的新途径。Pt二十四面体纳米晶由{730}、{520|高指数晶面围成，具有高密度的表面台阶原子，其催化活性和稳定性显著优于商品Pt纳米催化剂...Platinum group metal nanocatalysts are widely applied in a variety of important industrial fields such as automotive catalytic converters, fuel cells and petrochemical industry. Due to their rare reserves and high price, how to further improve the catalytic activity, stability and utilization efficiency of Pt group nanocatalysts has long been a key issue in above fields. One of the effective ways ...学位：理学博士院系专业：化学化工学院_物理化学(含化学物理)学号：2052008015017

Exploration of the Phenomenon Termed as Locally-Enhanced Interfacial Potential and Its Applications in the Electrochemically-controlled Sythesis

电化学学科历经200多年的发展，其基础理论日趋完善，而且作为实用性极强的学科在当今能源、材料、环境、生命等重要领域的应用中，电化学学科得到了飞速发展，成为化学领域发展态势最引人注目的学科。随着化石能源快速消耗和环境污染日益严重，特别是汽车工业快速增长，人类社会发展面临严峻的挑战。为应对这一挑战，高效、清洁的电化学能源转换和物质绿色电化学控制合成将发挥更加关键的作用，也面临更多的发展机遇。电化学涉及两相界面（固/液，液/液，固/固，大多数情况为电极/溶液界面）的电荷传递，一个最显著的特点是存在高达108Vcm-1的界面电场。电催化是电化学的一个重要分支，其优势在于催化剂与可控界面电场的协同效应，...After 200 years development, the basic theory of electrochemistry has been perfected gradually thus it also has been widely used as a highly practical discipline. The application of electrochemistry in many important areas such as energy, material, environment and life make it developed rapidly and became the most striking discipline in the field of chemistry. The electrochemical reaction involves...学位：博士后院系专业：物理科学与技术学院_理论物理学号：201317002

小扭口藓(Barbula indica)芽胞发育特征的实验研究

在光照培养箱中人工对照培养小扭口藓(Barbulaindica(Hook. )Spreng)的芽胞,显微镜下观察并记录其发育成配子体的全过程。结果表明:小扭口藓芽胞在3 ~4d即可萌发; 10d左右开始分化出绿丝体、轴丝体及假根; 18d,轴丝体上的侧枝顶端细胞以分生缢割的方式产生单细胞或多细胞芽胞; 40d,轴丝体上开始出现配子体原始细胞;之后,配子体原始细胞发育成桑椹状的幼小配子体。还对芽胞形态发育、生理生态及配子体发生过程的特点进行了分析和讨论。，CN 23-1480/

[書評論文] 移民は孤島の中で生きているのか？ : オーストラリアとシンガポールの流動的移民に着目する

departmental bulletin pape

Electrochemically shape-controlled formation of concave AuPd alloy nanoparticles on ITO substrate

运用电化学方波电位法, 在氧化铟锡(ITO)透明导电膜玻璃基底上实现AuPd纳米粒子的形状控制合成. 当固定方波下限电位0.30 V,; 上限电位分别为0.64和0.70 V时, 分别制备出内凹三八面体(TOH)和内凹六八面体(HOH) AuPd合金纳米粒子.; 运用扫描电镜(SEM)、X射线能量散射谱(EDX)和电化学循环伏安法表征所制备的纳米粒子, 结果表明所制备的AuPd纳米粒子在ITO上分散均匀,; 具有清晰的内凹三八面体和内凹六八面体的形状, Au:Pd元素比均接近3:1. 但由于Au比Pd的表面自由能低,; 导致Au在AuPd合金纳米粒子表面富集.发现从合成的TOH AuPd合金纳米粒子出发, 对其施加下限电位0.30 V、上限电位0.70; V的方波电位处理, 可实现由TOH向HOH形状转变; 延长方波电位处理时间仅改变AuPd合金纳米粒子的尺寸, 但HOH形状保持不变.Shape-control of AuPd alloy nanoparticles (AuPd NPs) substrated on; indium-tin oxide (ITO) was successfully achieved, for the first time, by; using electrochemical square-wave-potential (SWP) method. Concave; trisoctahedral AuPd alloy NPs (TOH AuPd NPs) and concave hexoctahedral; AuPd alloy NPs (HOH AuPd NPs) were prepared under SWP conditions with; lower potential of 0.3 V while different upper potentials of 0.64 and; 0.70 V, respectively. Different techniques including SEM, EDX and; electrochemical cyclic voltammetry were employed to characterize the; morphology and composition of AuPd alloy NPs. The results demonstrated; that the as-prepared TOH AuPd NPs and HOH AuPd NPs are uniform in shape; of correspondingly concave TOH and concave HOH, and are well dispersed; on the ITO substrate. The composition in terms of and Au:Pd atomic ratio; of both TOH and HOH AuPd alloy NPs is determined by EDX around 3:1.; However, a surface enrichment of Au on the AuPd NPs was observed, and is; ascribed to the lower surface energy of Au in comparison with that of; Pd. It has been found that, starting from the as-synthesized TOH AuPd; NPs, shape transformation from TOH to HOH can be accomplished by; applying a treatment of square wave with lower potential of 0.3 V and; upper potential of 0.7 V. Prolonging the treatment time results in; increasing the size of AuPd NPs, while the HOH shape is preserved.国家自然科学基

石墨电弧中C5环的原位捕获与形成

五元环是富勒烯的重要构筑基元,是形成凸多面体碳笼的关键因素,研究C5环的形成对理解富勒烯自下而上的生长机理有着重要的意义。该文通过在石墨电弧放电体系中引入氯源,原位捕获到了C5与C60的[4+2]环加成衍生物C60（C5Cl6）。对该分子进行了质谱和紫外-可见吸收光谱的表征,并利用X-射线单晶衍射明确了C60（C5Cl6）的分子结构。此外,还通过一系列C60衍生物的质谱表征,对C5环和C60（C5Cl6）结构的演进路线进行了分析。国家自然科学基金(21721001,21827801和51572231

Preparation of PdCoIr Tetrahedron Nanocatalysts and Its Performance toward Ethanol Oxidation Reaction

钯(Pd)基催化剂是直接乙醇燃料电池研究中广泛使用的催化剂,进一步提升其性能是推动燃料电池发展的重要方向。本文用一步水热法制备出四面体结构PdCo(PdCo tetrahedron,记为PdCo-TH)和少量铱(Ir)掺杂的PdCo四面体合金纳米粒子(记为PdCoIr-TH)。经TEM、ICP、XPS及CV等表征证实,PdCoIr-TH为三元合金纳米粒子,且掺杂的Ir元素倾向分布在催化剂表层。相比于商业Pd/C催化剂,PdCo-TH/C和PdCoIr-TH/C对乙醇电氧化的催化性能显著增强。研究结果表明,Pd9Co1Ir0.1-TH/C在低电位(< -0.25 V)下具有最高的乙醇电氧化活性和稳定性。Ir掺杂不仅提高了催化剂抗CO毒化的能力还有利于乙醇起始氧化电位负移。同时,随着Ir含量的增加,所制备的纳米催化剂的乙醇电氧化C1产物选择性也随之升高。针对不同组成催化剂反应性的差异,本文认为Co与Ir位点上容易产生OHad物种,这将有利于活性Pd位点上乙醇电氧化中间反应物种的有效转化。除了以上的各位点间的协同效应,三元合金的形成,进一步调控了Pd的d带电子结构,从而促进了催化剂反应性的改变。As a new energy conversion device, direct ethanol fuel cells (DEFCs) are widely concerned because of their remarkable advantages such as high theoretical energy density and wide fuel sources. However, the rapid development of DEFCs has been severely impeded due to the sluggish kinetic process and toxic intermediates especially in their anodic reactions. Palladium (Pd)-based materials are considered to be excellent anode catalysts for DEFCs, especially under alkaline conditions. And further improving their performance is an important direction to promote the development of DEFCs. Surface structure and composition are the key factors affecting the performance of catalysts which can be improved by reasonable regulation. It is reported that high-index faceted structures and element doping are beneficial to improve the performance of catalyst. In this work, the advantages of these two strategies were used comprehensively to prepare Pd-based catalysts with high efficiency. Palladium cobalt (PdCo) and Ir-doped PdCo tetrahedron alloy nanocatalysts (denoted by PdCo-TH and PdCoIr-TH, respectively) have been successfully prepared by one-step hydrothermal method. The characterization results of TEM, ICP, XPS and CV show that the PdCo-TH binary and PdCoIr-TH ternary alloys were formed, while Ir element was mainly distributed on the PdCoIr-TH surface. Compared with the commercial Pd/C, the PdCo-TH/C and PdCoIr-TH/C exhibited the enhanced catalytic properties toward ethanol oxidation reaction in alkaline solutions. Particularly, the Pd9Co1Ir0.1-TH/C catalyst showed the best activity and stability toward EOR, especially at low potentials (< -0.25 V). And Ir sites not only resisted CO poison effectively, but also shifted the initial oxidation potential of ethanol negatively. Meanwhile, the selectivity of C1 products during the electrocatalytic oxidation of ethanol has been greatly improved with the increase of Ir content. The enhanced reactivities of PdCo-TH/C and PdCoIr-TH/C could be attributed to: (a) The coexistence of Co sites and Ir sites on the surfaces can generate OHad species which can promote the oxidation of intermediate adsorbed species on Pd sites and (b) the negative shift in electron binding energy of Pd due to the addition of Ir may make reaction intermediates desorb more difficultly, which might make the reactivity of PdCoIr-TH/C differ from that of PdCo-TH/C. This research work has demostrated a strategic approach for future development in high efficiency catalysts used for DEFCs.国家自然科学基金项目(21802112);国家自然科学基金项目(21773198)通讯作者:黄蕊,孙世刚E-mail:[email protected];[email protected]:RuiHuang,Shi-GangSunE-mail:[email protected];[email protected]厦门大学化学化工学院,固体表面物理化学国家重点实验室,福建 厦门 361005State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, Chin

Flexible decapyrrylcorannulene hosts

球形笼状的富勒烯是上个世纪末最重要的科学发现之一，但对富勒烯的精确几何结构的认识却困难重重，原因是单晶中球形分子的取向往往是无序的，需通过笼外衍生或通过八乙基金属卟啉-富勒烯超分子主客体组装来固定富勒烯的取向，然后利用常用的单晶衍射分析技术来精确表征富勒烯的几何结构。然而许多富勒烯新结构因无法与卟啉主体形成高质量的单晶至今仍无法利用X射线衍射技术进行结构分析，直接制约了对富勒烯形成机理及结构-性能关系的深入认识。功能团簇材料创新研究群体的谢素原、张前炎课题组另辟蹊径地从曲面结构的十氯碗烯C20Cl10出发，合成了十吡咯取代的碗烯分子C20(C4H4N)10。结构分析表明该分子的结构特征是碗烯的碳框架与十个吡咯基团通过单键相连。实验还证明，用甲基去取代吡咯3, 4-位置的氢并不利于富勒烯与碗烯衍生物形成有序的超分子组装体，理论研究进一步诠释了十个吡咯‘手指’的集体贡献比单个碗烯‘手掌’更大的原因。该研究工作是功能团簇材料创新研究群体长期积累，并由校内外十多位研究人员共同努力完成。徐云彦（2014级硕士生）、田寒蕊（2014级博士生）和李姝慧（2016年进站博士后）为该论文共同第一作者。【Abstract】The assembly of spherical fullerenes, or buckyballs, into single crystals for crystallographic identification often suffers from disordered arrangement. Here we show a chiral configuration of decapyrrylcorannulene that has a concave ‘palm’ of corannulene and ten flexible electron-rich pyrryl group ‘fingers’ to mimic the smart molecular ‘hands’ for self-adaptably cradling various buckyballs in a (+)hand-ball-hand(−) mode. As exemplified by crystallographic identification of 15 buckyball structures representing pristine, exohedral, endohedral, dimeric and hetero-derivatization, the pyrryl groups twist with varying dihedral angles to adjust the interaction between decapyrrylcorannulene and fullerene. The self-adaptable electron-rich pyrryl groups, susceptible to methylation, are theoretically revealed to contribute more than the bowl-shaped palm of the corannulene in holding buckyball structures. The generality of the present decapyrrylcorannulene host with flexible pyrryl groups facilitates the visualization of numerous unknown/unsolved fullerenes by crystallography and the assembly of the otherwise close-packed spherical fullerenes into two-dimensional layered structures by intercalation.This research was supported by the National Natural Science Foundation of China (21771152, 21721001, 21827801, 51572231, 51572254, 21571151, 2170010228), the 973 Program of China (2014CB845601 and 2015CB932301), the China Postdoctoral Science Foundation (2016M602067), the National Key Research and Development Program of China (2017YFA0402800), and the Fundamental Research Funds for the Central Uni- versities (20720170028, 20720160084). Q.Y.Z. is particularly grateful to 21771152, 2015CB932301, 20720170028, 20720160084; S.F.Y. is particularly grateful to 51572254 and 2017YFA0402800; S.Y.X. is particularly grateful to 21721001 and 51572231; L.S.Z. is particularly grateful to 21827801; S.L.D. is particularly grateful to 21571151; S.H.L. is particularly grateful to 2170010228 and 2016M602067. 研究工作得到国家自然科学基金（21771152、21721001、21827801、51572231、51572254, 21571151、2170010228）、科技部973计划（2014CB845601、2015CB932301）和重点研发计划（2017YFA0402800）、国家博士后科学基金、中央高校基本科研业务费等的资助