Study of the pitch change of carbon coils during their growth

AbstractIn the present paper, carbon coils (CCs) were prepared by CVD. Their morphology, particularly pitch changes of the carbon coils prepared in different conditions were observed. It was found that the carbon source flow plays an important role in carbon coil growth and its morphology evolution. The appropriate atmosphere and flow rate is beneficial to the steady reactivity of catalyst particles. As such each carbon coil can grow well and have an exact growth rate. When the carbon supply is sufficient, the CCs exhibit close spiral and small coil diameter. When carbon supply decreases, small carbon supply leads to large pitch and coil diameter. CCs can be synthesized with different coil pitch under different carbon supply. This may be of great significance for the controllable preparation of carbon coil and its application

Study on catalyst for carbon nanotubes with special shape and its application for catalytic hydrogenation

摘要 几个世纪以来，在科学研究发展的道路上，几乎每一次的重大突破都与新材料的发现密切相关。自从1991年碳纳米管在高分辨率透射电镜下被发现以来，世界各国科学家掀起了纳米材料的研究热潮，由于这种新型碳材料特殊的管状结构和量子尺寸效应，使其具有良好机械力学性能和独特的电学性质。短短十年间，它已经广泛地影响了化学、物理、材料等众多科学领域并显示出巨大的应用前景。因此在如何温和条件下，大规模地、稳定地合成碳纳米管就成了当前研究的热门课题。 从目前的文献报道来看，合成碳纳米管的方法有电弧法、化学气相沉积法离子或激光溅射法、热解聚合物法、固相热解法等。但是，大量的碳纳米管主要采用电弧放电法及化学气...Abstract Every important breakthrough is related to development of new material in way to get knowledge for several centuries. Since carbon nanotubes(CNTs) was discovered by HRTEM in 1991, many scientist have dedicated to investigate nano-material. Because of their special tubular structure and effect of quantum size, they have many excellent properties, such as mechanistic and electronic prope...学位：理学硕士院系专业：化学化工学院_物理化学(含化学物理)学号：19992503

Structure and Performance of Cu-Fe Bimodal Support for Higher Alcohol Syntheses

Copper-iron modified bimodal support (M) with different mass fractions of Cu and Fe elements were prepared by an ultrasonic impregnation method. The catalytic performance for higher alcohol syntheses (HAS) was investigated in a fixed-bed flow reactor. Several techniques, including N-2 physical adsorption, temperature-programmed reduction/desorption of hydrogen, (H-2-TPR/TPD) and X-ray diffraction (XRD) were used to characterize the catalysts. The results indicated that the bimodal pore support was formed by the addition of small-pore silica sol into the macroporous silica gel. Increased amounts of small pore silica sol caused a decrease in pore size in the bimodal carrier. An increase in the Fe/Cu molar ratio facilitated the dispersion of CuO, promoted the reduction of CuO and Fe2O3 on the surface layers, and enhanced the interaction between the copper and iron species as well as the bimodal support inside the large pores. The copper was well-dispersed on the catalyst and the amount of iron carbides formed was high in catalysts with a high Fe/Cu molar ratio. Increasing the Fe/Cu mass ratio promoted the catalytic activity and thus facilitated the synthesis of higher alcohols. When the Fe/Cu molar ratio was increased to 30/20, the CO conversion and the yield of higher alcohols increased to 46% and 0.21 g . mL(-1) . h(-1), respectively. At the same time, the mass ratio of C2+OH/CH3OH reached 1.96.</p

Material and Energy Conversion of Integrated 100,t/a-Scale Bio-Jet Fuel-Range Hydrocarbon Production System via Aqueous Conversion of Biomass

以农业废弃物生物质为原料，利用水相转化技术，进行了百吨/年规模生物航油类烃(C8~C15)合成试运行.过程中采用两步酸解法分别将玉米秸秆中半纤维素和纤维素转化为糠醛和乙酰丙酸，作为生物质基平台化合物.在碱性条件下糠醛与乙酰丙酸经Aldol缩合反应实现碳链增长，生成的长链含氧中间体经过低温预加氢、高温加氢脱氧及精制，生成C8~C15范围内液态烃，可作为生物航油组分.以试运行实验结果为基础，进行了过程的物质与能量转化分析.结果表明，该路线获得液态烃类的基本性质满足合成航油ASTM-7566标准要求，并充分利用了原料中纤维素和半纤维素组分，是一条基于生物质的长链液态烃合成路线，1t航油约需10~12t干基玉米秸秆

A combined theoretical and experimental study on higher alcohol synthesis over Alkali-promoted Cu/ZnO/Al2O3 catalysts

在合成气制备低碳混合醇（C2+OH）领域，一系列不同类型的催化剂相继被开发出来，但是C2+OH的工业生产仍旧面临着很大的困难与挑战。比如，对于目前所开发的催化剂，C2+OH的选择性较低、副产物过多，从而导致碳资源利用率太低等等。本文的研究目标是提高合成气转化过程的碳资源利用率，因此本工作不仅需要考虑产物中C2+OH的选择性，同时还要兼顾副产物（比如，低碳烷烃以及CO2等）的生成。 本文首先考察了反应温度、两种常用的碱金属助剂K2O以及Cs2O的用量、反应空速以及原料气中CO2的浓度等一系列的反应参数对Cu/ZnO/Al2O3催化剂上C2+OH合成的影响，筛选出最佳的反应温度、碱金属助剂的用量...A variety of catalysts for higher alcohol（C2+OH）synthesis from syngas have been under development for potential commercial application, which are still facing challenges, including poor carbon efficiency due to low selectivity to desired products. In this contribution, we systematically studied the effects of temperature, loading of K2O and Cs2O, space velocity, and CO2 addition on the alkali-prom...学位：理学博士院系专业：化学化工学院_物理化学学号：2052013015387

Experimental Boosting of the Oxygen Reduction Activity of an Fe/N/C Catalyst by Sulfur Doping and Density Functional Theory Calculations

向Fe/N/C非贵金属催化剂中再引入S掺杂是进一步提高其氧还原催化活性的有效方法。为了探究活性提高的原因,本文以三聚氰胺-甲醛树脂为前驱体,氯化; 钙为模板,氯化铁为铁源,通过添加硫氰化钾(KSCN)来控制热解催化剂的S掺杂量。通过对比分析催化剂的物化性质,结合密度泛函理论(DFT)计算,分; 析S掺杂促进Fe/N/C催化剂氧还原活性的原因。透射电子显微镜(TEM)和N_2吸脱附等温线测试结果表明,S元素可抑制含铁纳米粒子的形成,促使形; 成多孔碳结构,提高比表面积。X射线光电子能谱(XPS)结果表明,适量S前驱体可实现较高的S掺杂含量,得到最优的活性,过量的S反而会导致Fe和S的; 掺杂量同时降低,影响活性。DFT计算结果表明在Fe-N_4大环中引入S掺杂,可增强O_2分子和中间体OOH与Fe-N_4结构中的Fe的相互作用,; 促进形成Fe―O键,从而导致O―O键的键能显著降低,为后续反应O―O键的断裂提供可能,促进ORR反应的进行。S doping in Fe/N/C non-precious metal catalysts is an effective approach to further improve their catalytic activity for the oxygen reduction reaction (ORR). However, the enhancement mechanism is not yet clear. Here, we synthesized an Fe/N/C catalyst using melamine-formaldehyde resin as the N and C precursors, CaCl2 as the template, and FeCl3 as the Fe precursor. The effects of S doping on the morphology, textural property, composition, and ORR catalytic activity were investigated by adding various amounts of KSCN as a precursor. Transmission electron microscopy (TEM) and N-2 adsorption-desorption isotherm results revealed that S prevented the growth of Fe-containing nanoparticles, and facilitated the formation of a porous structure, which increased both the catalyst surface area and mass transfer rate. X-ray photoelectron spectroscopy (XPS) results indicated that a suitable amount of S precursor led to a high doping level of S and provided the highest ORR activity. However, too much S in the precursor decreased the doping levels of both Fe and S, due to the formation of FeS, which could be completely removed by acid leaching. Density functional theory (DFT) calculations showed that the addition of S in an Fe-N-4 macrocycle could enhance the interaction strength of the Fe-O bond between the O-2 molecule or the intermediate OOHspecies and Fe in the Fe-N-4 structure, resulting in a significant decrease in the O-O bond energy, and may help in bond breaking in subsequent reactions, facilitating the ORR process.National Natural Science Foundation of China [21373175, 21621091

Solution synthesis and characterization of nickel nanosheets

具有形状各向异性的镍纳米晶在催化、磁记录、生物、电极材料等诸多领域具有重要的应用价值，因此探索一种简便可靠的合成方法来制备尺寸和形貌可控的镍纳米晶具有重要的研究意义。本论文通过有机液相法合成出了镍纳米片，研究了不同的制备参数对镍纳米晶的形貌、尺寸和结构的影响，并表征了其磁学性质和催化对硝基酚还原的性能。 本文首先以油胺作为溶剂和还原剂，乙酰丙酮镍作为镍前驱体，六羰基钨作为形核诱导剂，合成出了尺寸可控的镍纳米片。在较低的反应温度（160℃）和较短的保温时间下可以得到尺寸为15nm的镍纳米片，而升高反应温度至180℃并延长保温时间可以得到尺寸为70nm的镍纳米片。对样品进行XRD和选区电子衍射分...Ni nanocrystals with anisotropic shapes have important applications in many fields such as catalysis, magnetic recording, biology and electrode materials. Therefore, it has important research meanings to explore a simple and reliable synthetic method to prepare Ni nanocrystals with controlled size and morphology. In this thesis, we prepared Ni nanosheets by organic liquid phase method, investigate...学位：工学硕士院系专业：材料学院_材料加工工程学号：2072013115007

The study of chemical vapor deposition graphene growth mechanism based on isotope labelling technique

石墨烯是一种只由单个碳原子层构成的理想二维材料，自2004年首次被Novoselov等人采用胶带法从高定向热解石墨表面剥离出来后，其高电子迁移率，高热导，高硬度，高透光率等一系列独特优异的物理化学性质就不断被揭示，近十几年来一直保持着其研究热点的领先地位，同时还带动了其他二维层状材料的研究热潮。 目前石墨烯主要的制备方法分为以下四类：机械剥离法、氧化还原法、碳化硅外延法和化学气相沉积法；其中化学气相沉积法在生长高质量大面积石墨烯方面表现出很大的优势，尤其是在铜衬底上已获得30英寸的大尺寸单层石墨烯；再加上铜箔本身的低成本、易转移等特点，使得其成为实现石墨烯商业化生产的首要衬底；因此完善化学气...Graphene is an ideal two dimensional material with only one layer carbon atoms. Its unique physical and chemical properties such as high electronic mobility, high thermal conductivity, extreme mechanical hardness and high transparency have been revealed since it was first synthesized using the tape method in 2004. It has been keeping the leading research hotspot in recent years and has also motiva...学位：理学博士院系专业：物理科学与技术学院_凝聚态物理学号：1982012015389

Frontier Review of Inorganic Chemistry

作为化学学科里其它各分支学科的基础学科,近年来,无机化学的研究取得了较为突出的进展,主要表现在结构敏感催化材料的设计合成、高效能源材料、非线性光学晶体材料、分子筛及多孔材料、稀土化合物功能材料和先进碳材料等方面。本文就当代无机化学的上述前沿研究作以综述。As the basic discipline of other branches in the discipline of chemistry, inorganic chemistry has made impressing achievement in the recent years, which mainly lies in the fields of the designing and synthesis of structure-sensitivecatalytic materials, efficient energy materials, nonlinear optics crystalline material, molecular sieve and porous materials, rare earth compound function materials and advanced carbon materials, etc. This paper reviews above frontier research concerning contemporary inorganic chemistry