氮掺杂多孔石墨烯对硝基和偶氮化合物的催化还原性能——化学相关专业综合实验的设计与实践

针对溶有常见含硝基和偶氮化合物废水处理的问题，设计了无金属碳基催化剂制备及其对此类化合物催化还原的综合实验。实验以氧化石墨烯为原料，经水热法合成碳基催化剂氮掺杂多孔石墨烯或氮掺杂石墨烯，通过扫描电子显微镜、透射电子显微镜、比表面分析仪、X射线光电子能谱等对其结构、形貌和元素组成等进行表征，并研究其对硼氢化钠还原硝基和偶氮化合物的性能。该实验涉及碳基催化剂制备、表征和废水处理等多个实验环节，涵盖了物理化学、材料化学和环境化学等多个学科领域。通过该实验可以培养学生的科研思维，提高学生的科研动手能力和用化学知识解决实际问题的能力。     

氟化氢溶液无电沉积法制备W掺杂Ag树枝晶

应用无电沉积在氟化氢溶液制备W掺杂Ag树枝晶,样品由XPS,XRD,SEM和TEM表征,结果表明在Ag-W二元体系中,Ag的生长起主导作用,不受钨酸根离子而改变。提出W元素的掺杂方式,即W元素的掺杂是在银的沉积过程中通过化学吸附—钨酸根二聚体的氧原子与银原子的化学作用力而实现的。循环伏安法用于检测银氧间的化学键能的强弱。     

导电聚苯胺的合成、结构、性能和应用

概述了中国科学院长春应用化学研究所对导电聚苯胺合成、结构、性能和应用的研究.从合成可溶性的聚苯胺入手,阐明了聚苯胺的若干基本化学和结构问题,提出并证明了掺杂态聚苯胺的结构模型和掺杂机理;除了质子酸掺杂外,发现了聚苯胺的碘氧化掺杂、光助氧化掺杂和K+注入还原掺杂;开发了分别以环氧树脂和聚氨酯为载体的聚苯胺防腐涂料;运用掺杂剂诱导的溶解性,通过合成带聚乙二醇链的膦酸掺杂剂,实现了导电态聚苯胺的水体系加工.其中的聚苯胺树脂及防腐涂料的生产技术,已经完成中试,正在走向产业化.     

聚乙炔的离子注入法掺杂

<正> 离子注入是一种物理摻杂方法,在半导体器件的制备中已得到广泛的应用,它与常规的化学、电化学或热扩散掺杂相比具有一些特点:可以通过质量分析器选取单一的注入离子,故掺杂杂质的纯度高;根据注入离子的剂量和能量,精确控制到掺人杂质的数量和深度等等。近年来,采用离子注入技术进行掺杂,改变聚合物或其它绝缘材料表面性质的研究已逐步引起重视真视。     

氮、 硼掺杂石墨烯活性位点及其在氧化反应中作用的研究进展

随着绿色化学的逐渐推广,碳材料作为最有前途的绿色无金属催化剂而备受关注。通过对石墨烯引入杂原子进行化学掺杂是目前最常用于改良碳材料催化活性的有效方法。从结构上看,掺杂石墨烯内特定活性物种在催化过程中起到活性位点的作用,且催化剂的催化活性随活性位点含量增加而增强。且其内部活性位点含量可通过改变制备方法中制备条件实现调控,这有助于开发具有高催化活性的掺杂石墨烯催化剂。本文综述了氮掺杂石墨烯和硼掺杂石墨烯内可作为活性位点的官能团,提出制备方法对活性位点含量的影响,并讨论了内部活性位点在氧化反应中的作用。最后对未来研究方向提出了建议和展望,为开发更高效掺杂石墨烯催化剂提供了思路。     

La或N掺杂SiC纳米线的制备、场发射性能及第一性原理计算

采用化学气相沉积法和气相掺杂法, 分别制备了La 或N掺杂的SiC 纳米线. 利用场发射扫描电子显微镜(FE-SEM)、透射电子显微镜(TEM)、选区电子衍射(SAED)、高分辨透射电子显微镜(HRTEM)、X射线能量色散谱(EDS)分析和X射线衍射(XRD)等测试手段对两种产物的微观形貌、元素组成和物相结构进行了系统表征. 以合成产物作为阴极, 对其场发射性能进行测试, 结果表明: SiC 纳米线的开启电场值和阈值电场值由未掺杂的2.3、6.6 V·μm^-1分别降低为1.2、5.2 V·μm^-1(La 掺杂)和0.9、0.4 V·μm^-1(N 掺杂). 采用Material Studio 软件中的Castep 模块建立(3×3×2)晶格结构模型, 对未掺杂、La 或N掺杂SiC 的能带结构和态密度进行计算, 结果显示: La或N掺杂后, 在费米能级附近产生了新的La 5d或N 2p掺杂能级, 导致禁带宽度(带隙)变窄, 使得价带电子更容易跨越禁带进入导带, 从而改善SiC纳米线的场发射性能.     

离子掺杂氧化锌光催化纳米功能材料的制备及其应用

氧化锌是一种氧化还原电位高、激子结合能大（~60 meV）、物理和化学稳定性较好、廉价且无毒的半导体光催化剂。本文综述了掺杂氧化锌光催化剂的掺杂离子类型、制备方法、光催化效果及其作用机理。掺杂氧化锌的离子类型主要包括非金属离子单掺杂、金属离子（包括过渡金属离子和稀土金属离子）单掺杂和双离子共掺杂。离子掺杂后可在氧化锌晶格中引入更多的氧空穴或缺陷,为光致氧化反应提供更多的活性位点;或者引入杂质能级,扩大光吸收范围,增强可见光吸收能力。同时,掺杂的离子也可作为电子捕获中心,阻止光生电子-空穴对的复合,从而提高氧化锌光催化剂的性能。此外,文中还对掺杂氧化锌光催化剂在有机污染物降解、抗菌和光催化制氢等方面的应用进行了系统概述,并对其发展趋势作了展望。     

Rietveld全谱拟合表征掺杂ZnO陶瓷

通过Ｒｉｅｔｖｅｌｄ合谱拟合对掺杂多物相ＺｎＯ陶瓷的物相定量组成，所含尖晶石相的化学配比、晶粒大小和残余应和等结构参数同时进行了表征，即快又准，研究结果表明，掺杂ＺｎＯ陶瓷以保持原晶格常数和没有其它元素掺杂的较大颗粒的ＺｎＯ相淡主体，主分散的Ｂｉ２Ｏ３相与尖晶石相晶粒分散于ＺｎＯ晶粒间，尖晶石相的元素随产的掺杂组分配比不同而不同，利用全谱拟合精修确定了它们的元素组成。     

草酸根掺杂立方体溴化银乳剂颗粒的增感效应研究

使用反馈式微机控制双注乳化仪,在晶体生长过程中一定时间内,加入一定量的草酸盐,制得了草酸根离子处于晶体颗粒次表面的立方体溴化银微晶乳剂.对其实验过程的考察和感光性能的测试结果表明,(1)草酸根掺杂于次表面的溴化银乳剂与未掺杂乳剂相比较,无论是原始乳剂,还是经过化学增感,或用染料进行光谱增感后的乳剂,感光度都有明显提高(Sd/S0≥1.5),有明显的增感效应;(2)无论是原始乳剂,还是经过化学增感,或光谱增感后的乳剂,草酸根掺杂立方体溴化银乳剂颗粒的灰雾水平都不高;(3)草酸根掺杂立方体溴化银颗粒与甲酸根掺杂的溴化银乳剂相比,产生的增感效应相差不大;(4)与甲酸根掺杂立方体溴化银颗粒相比,草酸根掺杂立方体溴化银颗粒的制备方法明显较前者要简单得多,颗粒形状也优于前者.     

Pd/N共掺杂TiO_2的制备及其光催化活性

将纳米管TiO2浸入含尿素和硝酸钯的乙醇溶液中,将乙醇超声挥发后所得样品先在空气中600℃下煅烧,再在H2气氛中400℃中热还原,得到Pd/N共掺杂TiO2.分别采用DRS、X射线衍射仪及X射线光电子能谱仪分析了掺杂TiO2样品的光吸收能力、晶体结构及表面化学组成;并评价了其对紫外光和可见光照下丙烯降解反应的催化活性.结果表明,共掺杂TiO2样品的活性优于单一Pd或N掺杂TiO2.其原因在于,Pd和N共掺杂具有协同作用,从而共同提高了TiO2的光催化活性.     

Insights on Luminescent Micro- and Nanospheres of Infinite Coordination Polymers

Coordination polymers have been extensively studied in recent years. Some of these materials can exhibit several properties such as permanent porosity, high surface area, thermostability and light emission, as well as open sites for chemical functionalization. Concerning the fact that this kind of compounds are usually solids, the size and morphology of the particles are important parameters when an application is desired. Inside this context, there is a subclass of coordination polymers, named infinite coordination polymers (ICPs), which auto-organize as micro- or nanoparticles with low crystallinity. Specifically, the particles exhibiting spherical shapes and reduced sizes can be better dispersed, enter cells much easier than bulk crystals and be converted to inorganic materials by topotactic transformation. Luminescent ICPs, in particular, can find applications in several areas, such as sensing probes, light-emitting devices and bioimaging. In this review, we present the state-of-the-art of ICP-based spherical particles, including the growth mechanisms, some applications for luminescent ICPs and the challenges to overcome in future commercial usage of these materials.     

A comparison of INAA and ICP-MS/ICP-AES methods for the analysis of meteorite samples

Instrumental neutron activation analysis (INAA), inductively coupled plasma atomic emission spectrometry (ICP-AES) and ICP mass spectrometry (ICP-MS) (hereafter, ICPs) were applied to meteorite samples for the determination of elemental content. The analytical applicability and suitability of the three methods have been compared. Those comparisons led to the refinement of our analytical procedures for INAA and ICPs, yielding more reliable data. Our INAA data proved to be reliable enough for classifying meteorites, while the ICPs, especially ICP-MS, can characterize elemental abundance features in detail, as demonstrated by REE abundance patterns for the Allende meteorite. In this manner, INAA and ICPs can be used in a complementary fashion in cosmochemical studies.     

Formation of α-helix-based twisted ribbon-like fibrils from ionic-complementary peptides

Ionic-complementary peptides (ICPs) are well known for their strong propensity to form amyloid-like β-sheet fibrils. Here, we present the first example that α-helical based ICPs can self-assemble into a highly ordered fibrillar structure. Intriguingly, the individual α-helices in such fibrils are arranged shoulder-to-shoulder, making them distinct from conventional coiled-coil-based fibrils.     

Intrinsically conducting polymers for electromagnetic interference shielding

This paper summarizes and reviews the research on electromagnetic interference (EMI) shielding with intrinsically conducting polymers (ICPs), mainly polyaniline (PANI) and polypyrrole (PPY), and their composites in various frequency ranges. ICPs are new alternative candidates for EMI shielding applications due to their lightweight, corrosion resistance, ease of processing, and tunable conductivities as compared with typical metals. More importantly, the dominant shielding characteristic of absorption other than that of reflection for metals render ICPs more promising materials in applications requiring not only high EMI shielding effectiveness but also shielding by absorption, such as in stealth technology. Copyright © 2005 John Wiley & Sons, Ltd.     

Comment on a proposed excitation mechanism in argon ICPs

The author points to experimental results, published in the literature, which provide indirect evidence of overpopulations of highly excited levels of both argon and analyte species, with respect to the LTE populations, in the analytically favourable, non-thermal zone of toroidal ICPs. Considering this evidence and a mechanism proposed in the literature to explain results of measurements of spatial emission characteristics in ICPs, the author suggests the likeliness that the collisional-radiative model of Bates, Kingston, and MmcWhirter as elaborated by fujimoto for a so-called predominantly recombining plasma, might provide a key for understanding some basic phenomena in the non-thermal region of argon ICPs. The dominant mechanisms would then involve Penning ionisation by excited argon atoms (not exclusively metastables) and three-body ion-electron recombination.     

A computer-controlled direct sample insertion device for inductively coupled plasma-mass spectrometry

A direct sample insertion (DSI) device has been developed for application to inductively coupled plasma-mass spectrometry (ICP-MS). In a DSI device for use with ICPs, the sample is placed into or onto a probe with subsequent introduction of the sample carrying probe, via the central tube of the ICP torch, into the plasma. A mechanical, stepper-motor driven, computer controlled DSI device and software support system has been designed and developed that can easily be attached to a commercial ICP-MS system (Perkin-Elmer/SClEX Elan). This system allows the direct introduction of microliter volumes of liquids and milligram quantities of powdered/solid samples into the ICP-MS with little or no sample pre-treatment.     

Comparative study of analytical inductively-coupled argon-plasma discharges using different outer gases

The analytical capabilities of high power (2-4 kW) ICPs with argon as inner and intermediate gas and different outer gases (argon, nitrogen, oxygen and air) were studied under optimum and compromise operating conditions. Under the optimum conditions, the lowest detection limits for elements with sensitive atom lines (C, B, Zn) or ion lines (Mg, Mn, Fe, Cr, Ti, V) were achieved with argon as outer gas and an observation height of 13 mm. Under compromise conditions (3 kW, aerosol gas gauge-pressure 3 bar) the lowest detection limits for the atom lines were also found with a pure argon plasma at an observation height of 13 mm. For ion lines, however, the argon/oxygen and argon/nitrogen plasmas and an observation height of 8 mm were better. The detection limits were poorer in the presence of an aluminium matrix; under the optimum operating conditions, the relative increase in detection limit was smaller with the argon/oxygen and argon/air ICPs than with the pure argon or argon/nitrogen ICPs. It was found that the interferences arising from an easily ionizable matrix are lower with a diatomic gas than with argon as outer gas. The interferences when the argon/nitrogen, argon/oxygen and argon/air plasmas are used are similar and practically independent of the nebulizer-gas pressure applied.     

Investigation of the electroactivity of polymethylthiophene film for the corrosion protection of mild steel

The protection mechanism of intrinsically conducting polymers (ICPs) is still under discussion. Most of the discussions concentrate on the effect of the redox behavior and electroactivity of ICPs on the corrosion protection. In the present paper it is shown that polymethylthiophene (PMT) films electropolymerized on mild steel, with 2-(3-thienyl)ethylphosphonic acid used as adhesion promoter, show the desired redox activity. The interaction between the PMT film and some conventional coatings, and the influence of the pH of electrolyte, were investigated. It was shown that the electroactivity of PMT film is lost by the interaction with coatings of high nucleophilicity and is markedly decreased by immersion in an aqueous solution of pH 11.     

Microplasmas for chemical analysis: analytical tools or research toys?

An overview of the activities of the research groups that have been involved in fabrication, development and characterization of microplasmas for chemical analysis over the last few years is presented. Microplasmas covered include: miniature inductively coupled plasmas (ICPs); capacitively coupled plasmas (CCPs); microwave-induced plasmas (MIPs); a dielectric barrier discharge (DBD); microhollow cathode discharge (MCHD) or microstructure electrode (MSE) discharges, other microglow discharges (such as those formed between “liquid” electrodes); microplasmas formed in micrometer-diameter capillary tubes for gas chromatography (GC) or high-performance liquid chromatography (HPLC) applications, and a stabilized capacitive plasma (SCP) for GC applications. Sample introduction into microplasmas, in particular, into a microplasma device (MPD), battery operation of a MPD and of a mini- in-torch vaporization (ITV) microsample introduction system for MPDs, and questions of microplasma portability for use on site (e.g., in the field) are also briefly addressed using examples of current research. To emphasize the significance of sample introduction into microplasmas, some previously unpublished results from the author's laboratory have also been included. And an overall assessment of the state-of-the-art of analytical microplasma research is provided.     

Some theoretical and practical considerations to the application of linear photodiode arrays for inductively coupled plasma emission spectrometry

Expressions are developed and used to predict the performance of a linear photodiode array when used with a conventional dispersive spectrometer for inductively coupled plasma (ICP) atomic emission spectrometry in the 200 to 450 nm region. The photon flux from the ICP and the relative standard deviation (RSD) at high concentrations are used in the equations to calculate the degradation of performance to be expected at and above the detection limit for integration times up to 10 s. Significant degradation is predicted only below 230 nm, and this degradation is less than a factor of 10 at 200 nm for an ICP with an RSD of 0.2 %. One-second integration times are possible with noiser ICPs or at longer wavelengths without significant performance degradation by the photodiode array.