C60的产生与石墨晶面的关联（Ⅱ）

Ｃ_（６０）的产生与石墨晶面的关联（Ⅱ）谢兆雄，刘朝阳，王春儒，林逢辰，郑兰荪（厦门大学化学系，固体表面物理化学国家重点实验室，厦门，３６１００５）关键词Ｃ_（６０），球烯，激光烧蚀，高序热解石墨，六元环平面Ｃ６０及其它球烯是当今研究的热点，但有关其形...     

C70正负离子的激光引发聚合

Ｃ_（７０）正负离子的激光引发聚合刘朝阳，王春儒，黄荣彬，林逢辰，郑兰荪（固体表面物理化学国家重点实验室，厦门大学化学系，厦门，３６１００５）关键词Ｃ_（７０），聚合，激光等离子体Ｃ６０在激光作用下的进一步聚合是近来在Ｃ６０研究中的又一重要发现，Ｙｅｒ...     

C60硫衍生物—C60S^＋的气相合成

Ｃ_（６０）硫衍生物──Ｃ_（６０）Ｓ~＋的气相合成刘子阳，郝国仑，郭兴华，刘淑莹（中国科学院长春应用化学研究所，长春，１３００２２）关键词Ｃ_（６０），ＣＳ_２，离子－分子反应自实现Ｃ（６０）的宏观量合成以来［１］，通过将Ｃ（６０）进行化学衍生进而改变?..     

C60与聚苯乙烯活性种的反应

Ｃ_（６０）与聚苯乙烯活性种的反应汪长春，潘宝荣，府寿宽（复旦大学高分子科学系，上海，２００４３３）关键词高分子Ｃ_（６０）衍生物，聚苯乙烯阴离子活性种，Ｃ_（６０）自从Ｃ６０被常规量制备出以后［１］许多Ｃ６０的衍生物也已合成出来。研究发现，Ｃ６０及其?..     

PVK／C60电荷转移络合物的光谱研究

利用紫外光谱、荧光光谱研究了ＰＶＫ／Ｃ_（６０）~＊（Ｃ_（６０）~＊与Ｃ_（７０）混合物）体系的光谱行为，实验结果表明，ＰＶＫ与Ｃ_（６０）之间存在电荷转移络合作用。紫外光谱结果表明ＰＶＫ／Ｃ_（６０）~＊电荷转移络合物的特征吸收峰在４７４ｎｍ附近，这与理论计算结果相吻合．ＰＶＫ单元与Ｃ_（６０）之间的最佳匹配约为５：１．荧光光谱结果进一步证明了ＰＶＫ与Ｃ_（６０）~＊之间的电荷转移络合作用的存在。     

C60,C70与过氧苯甲酰反应的动力学研究

Ｃ_（６０）、Ｃ_（７０）与过氧苯甲酰反应的动力学研究胡波，薛万华，张法义，尚振锋，马克勤，臧雅茹，赵学庄（南开大学化学系，天津，３０００７１）关键词Ｃ_（６０），Ｃ_（７０），动力学Ｋｒａｔｓｃｈｍｅｒ等人［１］的发现使制备宏观量的Ｃ（６０）和Ｃ（７０...     

C_（60）－PNVC光电导功能材料的形态与结构研究

用高分辨~（１３）Ｃ核磁共振技术与扫描电镜法研究了Ｃ_（６０）修饰的聚乙烯咔唑（ＰＮＶＣ）光电导功能材料。结果表明，Ｃ_（６０）与ＰＮＶＣ共混时彼此间存在快速动态电荷转移行为；Ｃ_（６０）含量对化学修饰的ＰＮＶＣ结构影响显著。最后比较了Ｃ_（６０），ＰＮＶＣ及用金属有机化学法制备Ｃ_（６０）－ＰＮＶＣ共聚物的亚微观形态结构差异。     

C60（OH）x的简便合成及性质

Ｃ_（６０）（ＯＨ）_ｘ的简便合成及性质孙大勇，刘子阳，郭兴华，佘益民，周雨，刘淑莹（中国科学院长春应用化学研究所应用谱学开放实验室，长春，１３００２２）关键词Ｃ_（６０），水溶性富勒醇，钾，不稳定性，溶解度水溶性Ｃ６０化合物的合成及性质研究作为Ｃ６０?..     

C_（60）［Pd（PPh_3）_2］的合成及其对1－庚烯氢化反应的催化性能研究

在无水无氧氮气保护的条件下，制备Ｃ_（６０）的过渡金属络合物Ｃ_（６０）［Ｐｄ（ＰＰｈ_３）_２］，对其进行了表征．以此新络合物为催化剂，研究它对１－庚烯氢化反应的催化性能．结果表明，Ｃ_（６０）［ｐｄ（ＰＰｈ_３）_２］具有使１－庚烯环化生成１，２－二甲基环戊烷的独特催化活性．     

C_（60）~＋的Jahn－Teller结构畸变

用ＩＮＤＯ系列方法对Ｃ_（６０）的阳离子自由基Ｃ_（６０）~＋进行几何构型优化，得到Ｄ_（５ｄ）对称性的构型，表明Ｃ_（６０）~＋确实发生了Ｊａｈｎ－Ｔｅｌｌｅｒ结构畸变，形成７种键和４种不等同Ｃ原子，且单键变短，双键变长，键长趋于平均化，体系的正电荷和单电子主要分布在赤道附近，从而导致了赤道附近Ｃ原子的高反应活性。     

Atomic structure of highly ordered pyrolytic graphite doped with boron

Boron-doped carbon was prepared by the high-temperature reaction of B₂O₃ with the highly ordered pyrolytic graphite (HOPG). In order to reveal the effect of the boron doping on the HOPG structure, several experimental tools were employed such as X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning tunneling microscopy (STM), and atomic force microscopy (AFM). While the interlayer spacing of the graphite plane remains virtually unchanged, the boron doping makes the graphite plane of HOPG more disordered. Both the STM and the AFM studies show that the boron-doped HOPG surface is deformed not only in its bonding geometry, but also in its electronic structure. The overall results imply that the boron atom is substituted for the carbon atom rather than is intercalated into the graphite layers.     

Density functional study of methyl chemisorption on polycyclic aromatic hydrocarbons.

The reactions of methyl radicals with large (up to C(96)H(24)) polycyclic aromatic hydrocarbons (PAHs) are studied by density functional calculations to shed light on the experimentally observed deposition of carbon on highly oriented pyrolytic graphite (HOPG), which occurs when hot HOPG (decorated by nanometre-sized defects) is exposed to methyl radicals. The equilibrium structures of the reaction products, together with transition structures for PAHs up to the size of phenanthroperylene, are determined using the density functionals B3LYP, TPSSh, BP86 and TPSS. The structures are analysed by computing the pi orbital axis vector (POAV) and the altitude of the reactive carbon above the molecular plane of the PAH. The strongest C-CH(3) bonds are found at the edges of the PAHs, where the s character of the C orbital involved in the bond is roughly 25 % (sp(3) hybrid orbital). Carbon atoms inside the PAH form bonds with the methyl radical through atomic orbitals with about 16 % s character in the POAV analysis. These bonds are much weaker than those at the edges of the PAH, while the reactive carbon has moved about 40 pm above the molecular plane. At the edges, the PAH carbon atoms do not leave the molecular plane to this extent. The computed barrier heights and geometrical parameters of the transition structures are in agreement with Hammond's postulate, and the relative energies of all of the equilibrium structures can be rationalized by Hückel molecular orbital (HMO) theory.     

2-D self-assembly of the bis(phthalocyaninato)terbium(III) single-molecule magnet studied by scanning tunnelling microscopy

The presence of alkoxyl chains on the single-molecule magnet [(Pc')2Tb(III)] and its planar character favour its 2-D self-assembly on HOPG with the molecular plane parallel to the graphite surface, enabling us to control and/or predict the orientation of the preferential magnetization axis on the surface.     

Growth and reactions of SiOx/Si nanostructures on surface-templated molecule corrals

Surface-templated nanostructures on the highly oriented pyrolytic graphite (HOPG) basal plane were created by controlled Cs+- or Ga+)ion bombardment, followed by subsequent oxidation at high temperature, forming molecule corrals. The corrals were then used for template growth of SiOx/Si nanostructures. We demonstrate here that, for SiOx/Si nanostructures formed in controlled molecule corrals, the amount of silicon deposited on the surface is directly correlated with the corral density, making it possible to generate patterned SiOx/Si nanostructures on HOPG. Since the size, depth, position, and surface density of the nanostructures can be controlled on the HOPG, it is possible to produce surfaces with patterned or gradient functionalities for applications in fields such as biosensors, microelectronics, and biomaterials (e.g., neuron pathfinding). If desired, the SiOx structures can be reduced in size by etching in dilute HF, and further oxidation of the nanostructures is slow enough to provide plenty of time to functionalize them using ambient and solution reactions and to perform surface analysis. Organosilane monolayers on surface-templated SiOx/Si nanostructures were examined by X-ray photoelectron spectroscopy, time-of-flight secondary ion mas spectrometry, and atomic force microscopy. Silanes with long alkyl chains such as n-octadecyltrichlorosilane (C18) were found to both react on SiOx/Si nanostructures and to condense on the HOPG basal plane. Shorter-chain silanes, such as 11-bromoundicyltrimethoxysilane (C11) and 3-mercaptopropyltrimethoxysilane (C3) were found to react preferentially with SiOx/Si nanostructures, not HOPG. The SiOx/Si nanostructures were also found to be stable toward multiple chemical reactions. Selective modification of SiOx/Si nanostructures on the HOPG basal plane is thus achievable.     

Influence of ultrathin poly-(3,4-ethylenedioxythiophene) (PEDOT) film supports on the electrodeposition and electrocatalytic activity of discrete platinum nanoparticles

Coating a carbon electrode surface, specifically highly oriented pyrolytic graphite (HOPG) with an ultrathin film of poly-(3,4-ethylenedioxythiophene), PEDOT, provides a support on which a high density of uniformly dispersed Pt nanoparticles (NPs) can readily be formed by electrodeposition. The NPs tend to be much smaller, have a higher surface coverage, better dispersion and show a much lower tendency to aggregate, than Pt NPs produced under identical electrochemical conditions on HOPG alone. The electrocatalytic activity of the NPs was investigated for methanol (MeOH) and formic acid (HCOOH) oxidation. Significantly, for similarly prepared particles, Pt NP-PEDOT arrays exhibited higher catalytic activity (in terms of current density, based on the Pt area), towards MeOH oxidation, by an order of magnitude, and towards HCOOH oxidation at high potentials, than Pt NPs supported on native HOPG. These findings can be rationalised in terms of the enhanced oxidation of adsorbed CO, a key reaction intermediate and a catalyst poison. This research provides strong evidence that employing conducting polymers, such as PEDOT, as a support substrate, can greatly improve particular catalytic reactions, allowing for better catalyst utilisation in fuel cell technology.     

Influence of ultrathin poly-(3,4-ethylenedioxythiophene) (PEDOT) film supports on the electrodeposition and electrocatalytic activity of discrete platinum nanoparticles

Coating a carbon electrode surface, specifically highly oriented pyrolytic graphite (HOPG) with an ultrathin film of poly-(3,4-ethylenedioxythiophene), PEDOT, provides a support on which a high density of uniformly dispersed Pt nanoparticles (NPs) can readily be formed by electrodeposition. The NPs tend to be much smaller, have a higher surface coverage, better dispersion and show a much lower tendency to aggregate, than Pt NPs produced under identical electrochemical conditions on HOPG alone. The electrocatalytic activity of the NPs was investigated for methanol (MeOH) and formic acid (HCOOH) oxidation. Significantly, for similarly prepared particles, Pt NP-PEDOT arrays exhibited higher catalytic activity (in terms of current density, based on the Pt area), towards MeOH oxidation, by an order of magnitude, and towards HCOOH oxidation at high potentials, than Pt NPs supported on native HOPG. These findings can be rationalised in terms of the enhanced oxidation of adsorbed CO, a key reaction intermediate and a catalyst poison. This research provides strong evidence that employing conducting polymers, such as PEDOT, as a support substrate, can greatly improve particular catalytic reactions, allowing for better catalyst utilisation in fuel cell technology.

     

Investigation of modified basal plane pyrolytic graphite electrodes: definitive evidence for the electrocatalytic properties of the ends of carbon nanotubes

The basis of the electrocatalytic nature of multi-wall carbon nanotubes is suggested to reside in electron transfer from the ends of nanotubes, which structurally resemble the behaviour of edge plane (as opposed to basal plane) graphite, and is demonstrated via the comparison of the electrochemical oxidation of epinephrine and the electrochemical reduction of ferricyanide at nanotube-modified electrodes using different types of graphite electrodes and with C(60)-modified electrodes.     

The scattering of low energy C60 on graphite (0001) surfaces

The interaction between C₆₀ molecules with a graphite (0001) surface has been investigated by means of molecular dynamics simulations. The initial energies of the C60 molecules are 90 and 270 eV, respectively. An empirical model potential suggested by Takai et al. is used to describe the interaction between carbon atoms in the C₆₀ molecule and between the atoms forming the graphite substrate. The interaction between the C₆₀ atoms and the graphite atoms is modeled by a suitable Lennard-Jones potential. The resilience of scattered C₆₀ molecules is observed and its energy distribution is in reasonable agreement with available experimental data, showing no significant dependence of the rebounding translational energy on the incident kinetic energy. The energy partition in the collision has been analyzed in detail and a two-step collision model speculated in the experiments has been discussed based on the simulation results.     

Scanning tunneling microscopic investigations of the adsorption and segregation of carbon and sulfur on nickel single crystal surfaces

The adsorption and segregation of carbon or sulfur on Ni single crystal surfaces have been investigated by scanning tunneling microscopy (STM) and Auger electron spectroscopy (AES). Different adsorbate(segregate)-induced surface modifications have been detected in dependence on the original Ni surface orientation and the kind of nonmetal atoms: i) Adsorption of carbon from ethylene on Ni(111) at 6.7×10^–4 Pa and 1000K leads to the epitaxial growth of a graphitic carbon monolayer which exhibits the structure of the hexagonal basal plane of graphite. However, as is found for highly oriented pyrolytic graphite (HOPG), only three of six carbon atoms of the (0001) graphite plane are imaged by STM. In contrast, on Ni(771) at 663 to 1000 K carbon islands have been formed but no graphite monolayer formation is detected. This behavior can be understood by considering the aspects that no large-area epitaxy between the graphite basal plane and the Ni(110) terraces exists and that the surface carbon activity was too low to initiate substrate restructuring. ii) Segregation of sulfur (from the Ni bulk containing 5 to 7 ppm S) on Ni(110) at 1043K and _s0.4 ML initiates the growth of sulfur islands which show a c(2×2)-S overlayer structure, whereas on Ni(111) at 823K and _s0.2 ML (average value) a reconstructed surface phase is forming which can be described as an adsorbed two-dimensional sulfide Ni₂S.     

Structure and reactivity of Ru nanoparticles supported on modified graphite surfaces: a study of the model catalysts for ammonia synthesis

Supported ruthenium metal catalysts have higher activity than traditional iron-based catalysts used industrially for ammonia synthesis. A study of a model Ru/C catalyst was carried out to advance the understanding of structure and reactivity correlations in this structure-sensitive reaction where dinitrogen dissociation is the rate-limiting step. Ru particles were grown by chemical vapor deposition (CVD) via a Ru(3)(CO)(12) precursor on a highly oriented pyrolytic graphite (HOPG) surface modified with one-atomic-layer-deep holes mimicking activated carbon support. Scanning tunneling microscopy (STM) has been used to investigate the growth, structure, and morphology of the Ru particles. Thermal desorption of dissociatively adsorbed nitrogen has been used to evaluate the reactivity of the Ru/HOPG model catalysts. Two different Ru particle structures with different reactivities to N(2) dissociation have been identified. The initial sticking coefficient for N(2) dissociative adsorption on the Ru/HOPG model catalysts is approximately 10(-6), 4 orders larger compared to that of Ru single-crystal surfaces.