重油残渣基新型碳功能材料的研究进展

综述了以重油残渣为原料,采用化学气相沉积法、共炭化法和微波等离子体法可控制备气相生长碳纤维、碳微球、内包铁洋葱状富勒烯、纳米碳管、内包金属碳微米颗粒及定向碳纳米薄膜等各种高附加值碳材料;采用等离子体氧化法、酸处理法、化学还原法等方法对气相生长碳纤维和碳微球进行表面修饰,在产物表面引入含氧官能团,解决了可溶性碳材料的制备问题;在碳微球表面引入Pt纳米颗粒,使重油残渣基新型碳材料在表面修饰和功能化后可望成为性能优异的吸附和催化材料.     

纳米碳颗粒在催化中的应用及前景

概述了多壁富勒烯和新型纳米碳结构(纳米碳球)的表面修饰方法以及在催化中的应用研究现状,结果表明,化学氧化法对纳米碳颗粒进行表面修饰是有效的方法,可以改善其惰性表面,使其功能化.由于结构的独特性,纳米碳颗粒作为载体材料在电催化和某些脱氢反应中已经显示了较好的催化性能.预测了纳米碳在合成低碳烯烃中的潜在应用前景并为其在能源、化工领域中的应用提供了新的思路.     

碳微球表面功能化对镁基复合材料的增强作用

纳米碳材料增强相与镁基体间的两相界面结合程度直接影响着复合材料性能的提高,而使用化学改性法对增强相进行表面功能化可以有效改善两相间的界面结合度.为了进一步研究表面功能化在提升复合材料性能上所起的作用,本研究选用CVD法和水热法制备的碳微球(CVD-CMSs和HT-CMSs)为增强相,一是使用一步改性法(即使用表面活性剂PVP直接处理)对增强相进行表面功能化处理,制备出CVD-CMSs/Mg和HT-CMSs/Mg,考察CMSs上接枝的含氧官能团对表面功能化处理的效果;二是使用两步改性法(即先使用化学沉积法将MgO颗粒裹附到碳球表面,再用PVP进行处理)对增强相HT-CMSs进行功能化处理,并制备出HT-CMSs@MgO/Mg,与HT-CMSs/Mg对比来考察HT-CMSs上负载MgO纳米颗粒的作用.采用傅里叶红外光谱仪、X射线衍射仪、光学显微镜、高分辨透射电子显微镜和拉伸性能测试仪等对复合材料样品的组织、界面结构和力学性能进行表征和分析.结果表明:CMSs上携带的含氧官能团对表面功能化处理的效果以及增强相的分散性都具有积极作用,且经PVP一步改性后制得的复合材料的增强相与基体间有MgO薄膜生成,改善了增强相与基体的相容性;经两步改性后,负载在HT-CMSs表面的MgO纳米颗粒使两相间的MgO膜增厚,进一步提升了两相间的界面结合度,起到有效连接增强相与基体界面的作用,并最终使复合材料的拉伸性能得到提高.     

H_2O_2处理碳包覆铁纳米颗粒的表面特性及分散行为

采用体积分数30%的H2O2处理碳包覆铁纳米粒子外层的非晶态类石墨碳层,并将其超声分散于水介质中,通过改变pH值分析测定碳包覆铁纳米粒子表面zeta电位和粒径。结果表明:碳包覆铁纳米粒子非晶碳层的特殊结构可通过双氧水化学处理使其表面产生羧基和羟基;在强碱性介质下,羟基和羧基可强化颗粒间的静电斥力,提高碳包覆铁纳米粒子在水介质中的分散性能。当pH值约为11.5时,碳包覆铁纳米粒子表面zeta电位为48 mV,水合粒子粒径可达到110 nm。     

纳米碳颗粒负载碳化钼复合物的制备及其催化性能研究

利用爆炸辅助的化学气相沉积法成功地制备了纳米碳颗粒负载碳化钼的复合物,并利用TEM和XRD对合成纳米复合物的形貌和结构进行了表征;以环己烷脱氢反应为探针对其催化性能进行了评价,考察了钼含量对碳化钼复合物催化性能的影响.结果表明,纳米碳颗粒由有序度较低的石墨片层组成,形貌近似球形,粒度分布均匀,大小约为20nm,原位修饰的六方碳化钼分散在碳颗粒表面;钼含量不同,复合物对环己烷脱氢催化性能有较大差异,当钼含量为15%时,催化性能最好.     

碳微球负载钌纳米颗粒复合材料的化学镀制备

以碳微球(CMSs)为研究对象,首先通过不同的氧化方法对CMSs进行表面改性,再利用SnCl2敏化溶液对改性CMSs进行敏化.最后采用化学镀的方法制备Ru纳米颗粒/碳微球(Ru/CMSs)复合材料.考察了不同改性方法和敏化液用量对CMSs表面化学镀Ru的影响.采用场发射扫描电子显微镜、X射线衍射、X射线光电子能谱、热重分析和红外光谱等对产物的结构和形貌进行了表征和分析.结果表明,经400"C空气氧化改性后的CMSs制备出的Ru/CMSs样品纳米金属粒子均匀细小且加载率也较高;在其它条件不变的情况下,经0.5mol/L敏化液敏化处理制备的Ru/CMSs样品形貌最好.约15nm的钌纳米颗粒均匀地加载到碳微球表面.     

直流碳弧法制备碳包覆铁纳米颗粒机理研究

采用直流碳弧等离子体法成功制备了碳包覆铁纳米颗粒,利用透射电子显微镜和高分辨透射电子显微镜、X射线衍射、X射线能谱仪对样品的形貌、物相结构、化学成分和粒度进行表征分析,并对碳包覆纳米金属颗粒的形成机理进行初步探讨。结果表明:直流碳弧等离子体技术制备的碳包覆纳米金属颗粒具有明显的铁核(bcc-Fe)/碳壳(石墨层片)包覆结构,颗粒大多呈球形和椭球形,粒径分布在20~60nm范围,平均粒径为44nm,铁粒子外碳层的厚度为5~8nm。碳包覆铁纳米铁颗粒是通过颗粒内部固态形式的碳自行扩散至颗粒表面和颗粒外部气态形式的碳沉积到颗粒表面形成的。     

CeO2@SiO2纳米复合磨料的制备及其对光学石英玻璃的抛光性能

以无水乙醇为溶剂、氨水为催化剂,利用正硅酸乙酯水解所得的SiO2微球为内核,以硝酸亚铈为铈源、六亚甲基四胺为沉淀剂,采用化学沉淀法制备了具有草莓状包覆结构的CeO2@SiO2复合颗粒.利用X射线衍射仪、透射电子显微镜、场发射扫描电镜、能谱仪、X射线光电子能谱仪、纳米激光粒度分布仪等对所制备样品的结构进行了表征.将所制备的包覆结构CeO2@SiO2复合磨料用于光学石英玻璃的化学机械抛光,采用原子力显微镜观察了抛光表面的微观形貌,并测量了表面粗糙度.结果表明,所制备的CeO2@SiO2复合颗粒呈规则球形,粒度分布均匀,粒径为150～200nm,且具有明显的草莓状包覆结构,大量纳米CeO2颗粒紧密包覆在SiO2表面.AFM测量结果表明,抛光后玻璃表面划痕得到明显改善,在10μm×10μm范围内表面粗糙度RMS值由1.65nm降至0.484nm.     

多元醇法合成高比表面积纳米碳颗粒

提出了一种多元醇法敞开体系下制备具有高比表面积的非晶态纳米碳颗粒的方法.以三甘醇作为高沸点溶剂溶解溴化铵,将溶解有二茂铁的无水乙醇在200℃有氧气氛下滴入三甘醇中,利用溴化铵与二茂铁在溶剂中反应制备尺寸均匀的纳米碳颗粒.通过X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和氮气吸附-脱附等温线对纳米碳颗粒的微观结构进行了表征.结果表明碳颗粒近似为等轴状,尺寸分布在30～70nm之间,是完全的非晶态结构,比表面积为578.68m2/g,孔容为0.39cm3/g.反应物在三甘醇中的均匀溶解、反应是生成尺寸均一的纳米碳颗粒的主要因素.     

常压辉光放电等离子体制备荧光碳纳米粒子

采用常压辉光放电等离子体制备了超细荧光碳纳米粒子。分别采用聚乙二醇(PEG)2000和聚乙烯吡咯烷酮(PVP)20000作为表面活性剂和表面修饰剂,利用辉光放电等离子体射流产生的大量高能电子等活性粒子分解乙醇溶液制备碳纳米粒子。采用透射电子显微镜和荧光分光光度计对生成物的形貌和荧光特性进行了检测。结果表明,生成物为石墨相的荧光碳纳米颗粒。随着反应时间的延长,生成物的荧光强度增强;采用PEG-2000修饰后产物的荧光强度比采用PVP-20000更强;丝状放电模式下生成物的荧光强度高于辉光放电模式。制备的碳纳米颗粒的荧光量子产率为46.58%。     

Self-assembly of the Ag deposited ZnO/carbon nanospheres: A resourceful photocatalyst for efficient photocatalytic degradation of methylene blue dye in water

Carbon nanospheres (CNSs) are synthesized by pyrolysis of benzene at 1000?°C. Various UV-light photocatalysts of ZnO/CNSs and Ag-ZnO/CNSs (AZCN) composites are synthesized on the surface of CNSs using a facile chemical precipitation method. Morphological and optical properties of the as-synthesized photocatalysts are characterized by scanning electron microscopy, X-ray diffraction, energy dispersive spectroscopy, UV-Vis spectroscopy, photoluminescence and Raman spectroscopy. Photocatalytic degradation efficiency of methylene blue dye is investigated to examine the photocatalytic activity of synthesized photocatalysts. It is found that as-synthesized ZnO/CNSs composite can degrade higher methylene blue dye (～85.6%) after 25?min of UV irradiation in comparison with that of CNSs. A prominent improvement in the photodegradation is attained by depositing metal (Ag) particles on the surface of ZnO/CNSs composite. AZCN composite displays the enhanced photocatalytic degradation performance (～95% after 15?min of UV light) in high concentration of methylene blue dye. Furthermore, stability performance is studied by recycling the AZCN composite photocatalyst. It is found that the photocatalytic activity of AZCN composite is only slightly decreased even after five cycles. Present work demonstrates that AZCN composite show a great potential in the treatment of organic pollutants for wastewater treatment.     

Carbon nanoscrolls: synthesis and applications

Carbon nanoscrolls (CNSs), as an emerging family member of carbon nanomaterials, are a spirally wrapped 2D graphene sheet with a 1D tubular structure resembling that of multi-walled carbon nanotube. Due to its unique topological structure, CNSs not only share the remarkable mechanical, electronic properties and thermal conductivity exhibited by carbon nanotubes and graphene but also are expected to exhibit novel features. So they have attracted much attention from material scientists, chemists and physicists. Here, we review the research advances of preparative strategies of 1D CNSs with arc-discharge, CVD, self-scrolling, freeze-drying, cold quenching, functional groups/nanoparticles modification, mechanical ball milling, ultrasound-assisted and Langmuir–Blodgett methods, and potential applications in lithium ion/sulfur bateries, fuel Cells, supercapacitors, hydrogen storage, sensors, oscillators, photocatalytic materials and the other applications. We believe that CNSs will become another bright star after CNTs and graphene in the foreseeable future.     

Ultraviolet Photoluminescence of Carbon Nanospheres and its Surface Plasmon‐Induced Enhancement

Ultraviolet (UV) light can be used in versatile applications ranging from photoelectronic devices to biomedical imaging. In the development of new UV light sources, in this study, stable UV emission at ≈350 nm is unprecedentedly obtained from carbon nanospheres (CNSs). The origin of the UV fluorescence is comprehensively investigated via various characterization methods, including Raman and Fourier transform infrared analyses, with comparison to the visible emission of carbon nanodots. Based on the density functional calculations, the UV fluorescence is assigned to the carbon nanostructures bonded to bridging O atoms and dangling –OH groups. Moreover, a twofold enhancement in the UV emission is acquired for Au‐carbon core‐shell nanospheres (Au‐CNSs). This remarkable modification of the UV emission is primarily ascribed to charge transfer between the CNSs and the Au surface.     

Influence of architecture on the Raman spectra of acid-treated carbon nanostructures

Raman spectroscopy was used to characterise 11 varieties of carbon nanostructures (CNSs) consisting on seven varieties of commercial multi-walled carbon nanotubes, two types of carbon nanofibres and two types of lab-synthesised single-walled carbon nanotubes. The Raman spectra of these CNSs provided information on the structural ordering of the as-received (or as-synthesised) material. Additionally, the CNSs were chemically treated by two mixtures of nitric and sulphuric acids at markedly different concentrations and then characterised by Raman spectroscopy. The features of the G and D Raman bands of the CNSs were used to assess structural modifications and generation of defects induced by the acid treatments. Changes in the Raman spectra before and after acidic treatment depend strongly on the initial intensity ratio of the G to D bands and the architecture (number of layers or diameter) of the CNSs.     

Effect of the nature the carbon precursor on the physico-chemical characteristics of the resulting activated carbon materials

Carbon materials, including amorphous carbon, graphite, carbon nanospheres (CNSs) and different types of carbon nanofibers (CNFs) [platelet, herringbone and ribbon], were chemically activated using KOH. The pore structure of carbon materials was analyzed using N₂/77 K adsorption isotherms. The presence of oxygen groups was analyzed by temperature programmed desorption in He and acid–base titration. The structural order of the materials was studied by X-ray diffraction and temperature programmed oxidation. The morphology and diameter distribution of CNFs and CNSs were characterized by transmission electron microscopy. The materials were also characterized by temperature-desorption programmed of H₂ and elemental composition. The ways in which the different structures were activated are described, showing the type of pores generated. Relationships between carbon yield, removed carbon, activation degree and graphitic character were also examined. The oxygen content in the form of oxygen-containing surface groups increased after the activation giving qualitative information about them. The average diameter of both CNFs and CNSs was decreased after the activation process as consequence of the changes produced on the material surface.     

Effect of activated carbons modification on porosity, surface structure and phenol adsorption

The primary objective of this work was the examination of modified activated carbons with tailored adsorption capacity properties. Production of activated carbons with desired properties was accomplished by modification of surface functional groups and introduction of acidic/basic properties. Modification of an activated carbon was performed using partial oxygen gasification, nitric acid treatment, urea impregnation followed by pyrolysis and pyrolysis in a urea saturated stream. The surface properties of the produced samples were estimated by the multibasic titration method of Boehm and by the CO/CO2 gas evolution profiles, while pore structure development was measured by the N2 and CO2 gas adsorption isotherms. Oxygen gasification resulted in samples with surface area slightly lower that the raw activated carbon; the introduction of surface functional groups depended upon the severity of the treatment: carbonylic and phenolic type groups were introduced in all partially gasified samples, while low temperatures and short reaction times enhanced the basic character of the carbon. However, nitric acid treatment resulted in the introduction of high nitrogen amounts in the samples, the reduction of surface area and the development of a surface containing carboxylic, lactonic, phenolic and carbonylic groups with negligible HCl neutralization capacity. Treatment of activated carbon by urea supported the formation of basic groups and carbonyls. The presence of surface functional groups affected the adsorption capacity of the produced samples for the removal of specific pollutants such as phenols. Urea treated samples with a basic character and high nitrogen content presented the highest phenol uptake capacity; nitric acid treated carbons and oxygen gasified samples presented an acidic surface functionality and a low phenol adsorption capacity. The beneficial role of nitrogen on phenol adsorption was attributed to adsorbate-adsorbent interactions.     

热处理活性半焦的表面性质和SO2脱除活性

前驱体和表面改性过程都影响着活性半焦脱除SO2的活性.在氮气中、800℃下对原料半焦进行热处理,并在固定床反应器上测试了其脱除SO2的活性.利用酸碱滴定、工业分析和元素分析、X-射线光电子能谱(XPS)、傅立叶转换红外光谱(FTIR)等表征原料半焦和活性半焦表面化学性质.结果表明:石墨碳是原料半焦和活性半焦样品表面的主要碳功能团.表面C=O基团(酮、内酯、羰和醌类中)和吡咯-N分别是原料半焦表面的氧、氮功能团.热处理导致半焦表面含氧基团分解、表面含氧和含氮基团分布改变、表面C=O基团(酮、内酯、羰和醌类中)明显下降;而化学吸附氧和水增加,吡咯-N变成类吡啶结构.醚类和π - π* 离域基团的增加提高了活性半焦表面的碱性.热处理提高了活性半焦脱除SO2的活性.影响SO2脱除活性的表面基团可能是具有碱性性质的醚类、π - π* 离域及含氮基团.     

Sustainable and high-quality synthesis of carbon nanospheres with excellent dispersibility via synergistic external pressure- and PSSMA-assisted hydrothermal carbonization

Strict control of the monodispersity and size of hydrothermal carbon nanospheres (CNSs) with a size less than 150 nm is a prerequisite for many applications. However, designing and achieving the mass production of high-quality glucose-derived CNSs have been very challenging. Herein, we successfully synthesize PCNSs-PSSMA through a simple method that is synergistically assisted by an external pressure (2.0 MPa) and a small amount of poly(4-styrenesulfonic acid-co-maleic acid) sodium salt (PSSMA). The mechanism of the external pressure and PSSMA effect on the synthesis of PCNSs-PSSMA is investigated. On the one hand, the pressure and PSSMA can increase the glucose hydrothermal carbonation (HTC) rate and increase the number of carbon nuclei. On the other hand, PSSMA adsorbs on the surface of the CNSs to inhibit their growth so that more raw materials can be used for nucleation. When limited by the raw materials, it is difficult for CNSs to continue to grow. Furthermore, we also verify that PCNSs-PSSMA is superior in terms of adsorption and catalysis to large carbon spheres prepared by traditional methods. Our findings provide potential guidance for the mass production of other small particle size nanomaterials.     

Surface properties of activated carbon treated by cold plasma heating

To modify the surface properties of activated carbon powders, we have applied the cold plasma treatment method. The cold plasma was used to be generated in the evacuated reactor vessel by 2.45 GHz microwave irradiation. In this paper, changes of surface properties such as distribution of acidic functional groups and roughness morphology were examined. By the cold plasma treatment, activated carbons with large specific surface area of ca. 2000 m²/g or more could be prepared in a minute. The amount of every gaseous organic compound adsorbed on the unit gram of treated activated carbons was more increased that on the unit gram of untreated carbons. Especially, the adsorbed amount of carbon disulfide was remarkably increased even if it was compared by the amount per unit surface area. These results suggest that the surface property of the sample was modified by the plasma treatment. It became apparent by observing SEM photographs that dust and impure particles in macropores of activated carbons were far more reduced by the plasma treatment than by the conventional heating in an electric furnace under vacuum. In addition, a bubble-like surface morphology of the sample was observed by AEM measurement. The amount of acidic functional groups at the surface was determined by using the Boehm's titration method. Consequently, the increase of lactone groups and the decrease of carboxyl groups were also observed.     

电感耦合等离子体对HDPE粉体的表面处理

用搅拌式电感耦合等离子体反应器对高密度聚乙烯（HDPE）粉体进行表面处理,采用水接触角、红外光谱（FT-IR）和X射线光电子能谱（XPS）对等离子体处理前后HDPE粉体的水接触角、表面成分的变化进行分析。实验结果表明,随着等离子体处理时间延长和放电功率增加,水接触角减小。在功率100W处理30min后,水接触角从处理前...