Exoelectron Emission of a Carbon Nanomaterial

The exoemission properties of a Taunite carbon nanomaterial consisting of nanosized multiwalled nanotubes and nanofibers were investigated by thermally stimulated exoelectron emission (TSEE). The TSEE spectra of the carbon nanomaterial differed from the spectra of pressed graphite. It was assumed that defect—adsorbate complexes were emission-active centers on the surface of the nanomaterial     

激光辐照对二茂铁掺杂单壁碳纳米管的影响

以单壁碳纳米管和二茂铁为原料, 采用气相扩散法合成填充率较高的二茂铁掺杂单壁碳纳米管(Fc@SWNTs)的复合材料. 考察激光辐射对样品的影响, 结果表明, 当激光功率达到20 mW时, 对样品进行10 s辐照, 样品的拉曼光谱出现了稳定的新峰. 对比分析发现, 二茂铁在激光辐照后形成了碳化铁, 同时部分碳源转化成碳管形成了双层碳管. 表明碳化铁是二茂铁裂解向内层碳管转化的中间产物.     

Cyclic Voltammetric Studies of a Pyrolytic Carbon Film Electrode and the Effect of Laser Irradiation

The effects of laser irradiation with a small N₂ laser on the reactivation of a pyrolytic carbon (PC) film electrode were investigated. Cyclic voltammetry, Raman spectroscopy and scanning electron microscopy (SEM) were used to characterize the electrode. The electrode response decayed during the solution exposure but could be restored to a good performance via this reactivation method. It was found that the effect of laser to promote electron transfer was desorption the physisorbed impurities to exposure more active sites on the surface. Also, the electrochemical results were compared to the results of organic solvent washing and anodization.     

Photochromic Transformations of Spiro Compounds: 2. The Kinetics of Photocoloration under Continuous Irradiation

The kinetics of photocoloration of spiro compounds under continuous UV irradiation were analyzed. Using spirooxazine as an example, it was shown that the shape of the kinetic curve of spirooxazine absorbance in the course of photocoloration is the most sensitive to the photocoloration quantum yield and the molar decadic absorption coefficient of the colored form in the visible spectral region. The photocoloration rate was found to increase with increasing temperature as a result of the temperature dependence of the photocoloration quantum yield. The activation energies for photocoloration E _col and for thermal bleaching E _bleach were determined for a series of spiropyrans, and it was found that E _col < E _bleach.     

Elemental Boron for Efficient Carbon Dioxide Reduction under Light Irradiation

The photoreduction of CO₂ is attractive for the production of renewable fuels and the mitigation of global warming. Herein, we report an efficient method for CO₂ reduction over elemental boron catalysts in the presence of only water and light irradiation through a photothermocatalytic process. Owing to its high solar‐light absorption and effective photothermal conversion, the illuminated boron catalyst experiences remarkable self‐heating. This process favors CO₂ activation and also induces localized boron hydrolysis to in situ produce H₂ as an active proton source and electron donor for CO₂ reduction as well as boron oxides as promoters of CO₂ adsorption. These synergistic effects, in combination with the unique catalytic properties of boron, are proposed to account for the efficiency of the CO₂ reduction. This study highlights the promise of photothermocatalytic strategies for CO₂ conversion and also opens new avenues towards the development of related solar‐energy utilization schemes.     

Pulsed TEA CO2 Laser Irradiation of Titanium in Nitrogen and Carbon Dioxide Gases

Surface changes created by interaction of transversely excited atmospheric carbon dioxide (TEA CO₂) laser with titanium target/implant in nitrogen and carbon dioxide gas were studied. TEA CO₂ laser operated at 10.6 μm, pulse length of 100 ns and fluence of ∼17 J/cm² which was sufficient for inducing surface modifications. Induced changes depend on the gas used. In both gases the grain structure was produced (central irradiated zone) but its forms were diverse, (N₂: irregular shape; CO₂: hill-like forms). Hydrodynamic features at peripheral zone, like resolidified droplets, were recorded only in CO₂ gas. Elemental analysis of the titanium target surface indicated that under a nitrogen atmosphere surface nitridation occurred. In addition, irradiation in both gases was followed by appearance of plasma in front of the target. The existence of plasma indicates relatively high temperatures created above the target surface offering a sterilizing effect.

     

Ionization and Dissociation of Benzene and Aniline under Deep Ultraviolet Laser Irradiation

We report a study on photo-ionization of benzene and aniline with incidental subsequent dissociation by the customized reflection time-of-flight mass spectrometer utilizing a deep ultraviolet 177.3 nm laser. Highly efficient ionization of benzene is observed with a weak C\begin{document}$ _4 $\end{document}H\begin{document}$ _3 $\end{document}\begin{document}$ ^+ $\end{document} fragment formed by undergoing disproportional C\begin{document}$ - $\end{document}C bond dissociation. In comparison, a major C\begin{document}$ _5 $\end{document}H\begin{document}$ _6 $\end{document}\begin{document}$ ^{+\cdot} $\end{document} fragment and a minor C\begin{document}$ _6 $\end{document}H\begin{document}$ _6 $\end{document}\begin{document}$ ^{+\cdot} $\end{document} radical are produced in the ionization of aniline pertaining to the removal of CNH\begin{document}$ ^\cdot $\end{document} and NH\begin{document}$ ^\cdot $\end{document} radicals, respectively. First-principles calculation is employed to reveal the photo-dissociation pathways of these two molecules having a structural difference of just an amino group. It is demonstrated that hydrogen atom transfer plays an important role in the cleavage of C\begin{document}$ - $\end{document}C or C\begin{document}$ - $\end{document}N bonds in benzene and aniline ions. This study is helpful to understand the underlying mechanisms of chemical bond fracture of benzene ring and related aromatic molecules.     

Decoration of Carbon Nanomaterial Powders with Dispersed Platinum Metal Particles

Russian Journal of Applied Chemistry - Carbon nanomaterials (fullerite, detonation nanodiamonds, Taunit, fullerenol, fullerene-containing black) were decorated with platinum group metal...     

Interfacing High-Energy Charge-Transfer States to a Near-IR Sensitizer for Efficient Electron Transfer upon Near-IR Irradiation

Push–pull systems comprising of triphenylamine–tetracyanobutadiene (TPA-TCBD), a high-energy charge-transfer species, are linked to a near-IR sensitizer, azaBODIPY, for promoting excited-state CS. These systems revealed panchromatic absorption owing to intramolecular CT and near-IR absorbing azaBODIPY. Using electrochemical and computational studies, energy levels were established to visualize excited state events. Fs-TA studies were performed to monitor excited state CT events. From target analysis, the effect of solvent polarity, number of linked CT entities, and excitation wavelength dependence in governing the lifetime of CS states was established. Electron exchange between two TPA-TCBD entities in 3 seem to prolong lifetime of the CS state. We have been successful in demonstrating efficient CS upon both high-energy CT and low-energy near-IR excitations, signifying importance of these push–pull systems for optoelectronic applications operating in the wide optical window.     

碳纳米粒子:合成及可见光催化降解萘酚绿

以酒石酸和酪氨酸为起始反应物,乙二醇为溶剂,采用溶剂热法一步合成了高发光强度的碳纳米粒子。利用XRD、TEM、FTIR和荧光光谱对碳纳米粒子的物相、形貌和粒径、表面基团及发光性能进行了表征。结果表明,合成的碳纳米粒子为粒径分布集中的球形,粒径10~30 nm,分散性好,表面富含-COOH、-OH等官能团,具有激发波长依赖的光致发光特性。考察了反应温度、酒石酸与酪氨酸质量比对碳纳米粒子发光性能的影响。研究了碳纳米粒子/H2O2催化体系对萘酚绿的降解性能,结果表明:130 mg·L-1的萘酚绿溶液,可见光照射3.5 h降解率可以达到96%。荧光光谱法表征指明降解过程中有羟基自由基生成。     

Fe-N共掺杂纳米碳材料的形貌对电化学还原反应的影响

众所周知,石墨烯片（GS）和碳纳米管是能源转化和储存应用中有效的催化剂. 然而,过渡金属基氮（N）掺杂的体系中经常形成GS和碳纳米管的复合物,使得该体系内的构效关系研究变得十分困难. 为了可控制备出含有理想物种的催化剂,作者尝试通过利用氮对碳纳米管生长的效应调节生成产物的形貌. 本文中,作者采用一步法制备了一系列Fe-N共掺杂的GS、GS/竹节碳纳米管(BCNTs)复合物及BCNTs催化剂. 为了评估碳形貌对催化剂性能的影响,作者采用氧气还原反应（ORR）及二氧化碳还原反应（CO₂RR）作为模型反应. 电化学测试结果表明,所有的样品当中仅含BCNTs的催化剂表现出最好的ORR活性（起始电位E_onset = 1.02 V_RHE）及CO₂RR活性（CO生成法拉第效率FE_CO = 91.1%,-0.6 V_RHE）. 进一步的研究表明,优异的活性与独特的BCNTs中存在的缺陷、较大的比表面积、高含量的吡啶N及FeN_x相关. 该工作加深了作者对形貌相关的ORR及CO₂RR过程的认识和理解.     

Structural Study of Inclusion Complex of Andrographolide with β-Cyclodextrin Prepared under Microwave Irradiation

Andrographolide (Andro) (Figure 1) is a diterpene lactone isolated from Andrographis paniculate Nees1. It has showed several biological activities including analgesic, antipyretic and anti-inflammatory effects2. However, its poor water solubility and unstability towards oxygen restrained its application. In pharmaceutics, b-CD is used to increase solubility and stability3. We have prepared the inclusion compound of Andro/b-CD (Figure 2) under microwave irradiation4. It has been found…     

Structural and Morphological Transformations of Covalent Organic Nanotubes

Covalent organic nanotubes (CONTs) are porous one-dimensional frameworks connected through imine bonds via Schiff base condensation between aldehydes and amines. The presence of two amine groups at the ortho position in the structurally demanding tetraaminotriptycene (TAT) building block leads to multiple reaction pathways between the ditopic aldehyde and the tetratopic amine. We have synthesized five different monomers of CONT-1 by the Schiff base condensation reaction between TAT and o-anisaldehyde. The conversion of imine to imidazole bonding in a monomer is probed using NMR, mass spectrometry, and X-ray diffraction techniques. Solid-state NMR provide insights into the CONTs’ structural connectivity. A theoretical investigation suggests that the π-π stacking could be the driving force for rapid imine to imidazole conversion within the CONT-1. Microscopic imaging sheds further light on the self-assembly process of the CONTs, indicating both head-to-head and side-by-side assembly.     

Adsorption of 1,2-Dichlorobenzene on a Carbon Nanomaterial Prepared by Decomposition of 1,2-Dichloroethane on Nickel Alloys

Russian Journal of Applied Chemistry - Concept of complex processing of chlorinated hydrocarbons, involving catalytic decomposition of 1,2-dichloroethane on Ni–M alloys to obtain a carbon...     

碳自掺杂石墨相氮化碳纳米片的制备及其在可见光照射下的光解水产氢性能

石墨相氮化碳(g-C3N4)由于具有对可见光吸收范围较窄和光生载流子分离效率低等缺陷,其光解水产氢活性较差.我们采用简单的一步热共聚法,以尿素和2,4,6-三氨基嘧啶(TAPD)混合物为前驱物,制备碳自掺杂纳米片(CNNS-x,xmg代表掺入TAPD的质量).X射线衍射(XRD)、元素分析(EA)和X射线光电子能谱(X...     

On the Theory of Structural Transformations in Magnetic Fluids

Results of studying a new scenario of condensation phase transition in the ensemble of ferrofluid particles are reported. Phase transition in this ensemble starts with the formation of chain clusters. Chains whose length exceeds a certain critical value dependent on temperature and magnetic field undergo collapse and are transformed into very dense globules. The globule evolution leads to the separation of ferrofluid into two phases with different particle density. Initial (chain collapse) and final (equilibrium) stages of phase transition are investigated. Calculations of the critical length of a chain corresponding to its collapse, as well as the characteristics of dense phase at the final separation stage are in good agreement with the results of known experiments.     

微波辐照下泡沫陶瓷担载镍催化剂上CH4/CO2重整制合成气反应

制备了吸波性良好的泡沫陶瓷担载镍的甲烷／二氧化碳重整催化剂,并考察了催化剂在微波场中的升温行为;研究了微波加热与常规加热对甲烷／二氧化碳重整制合成反应的影响,发现微波辐照下能有效地消除反应积炭;同时,在达到相同转化率和选择性时,微波加热方式下催化剂床层的温度远低于常规加热方式下催化床床层的温度;在微波加热方式下,８００℃反应时产物中Ｈ２／ＣＯ体积比接近于１。