氮化硼纳米管的合成与表征

以氧化铁和无定型硼粉为原料,反应气氛为碳气氛,在1 400℃下利用化学气相沉积法（CVD）制备出氮化硼纳米管。X射线研究表明,对应着六方氮化硼晶面的特征衍射峰非常清晰。采用扫描电子显微镜（SEM）对样品的结构与形貌进行表征,结果表明,样品属于一端开口的竹节状BN纳米管。     

Reaction and Formation of Crystalline Silicon Oxynitride in Si–O–N Systems under Solid High Pressure

Oxidized amorphous Si₃N₄ and SiO₂ powders were pressed alone or as a mixture under high pressure (1.0–5.0 GPa) at high temperatures (800–1700°C). Formation of crystalline silicon oxynitride (Si₂ON₂) was observed from amorphous silicon nitride (Si₃N₄) powders containing 5.8 wt% oxygen at 1.0 GPa and 1400°C. The Si₂ON₂ coexisted with β-Si₃N₄ with a weight fraction of 40 wt%, suggesting that all oxygen in the powders participated in the reaction to form Si₂ON₂. Pressing a mixture of amorphous Si₃N₄ of lower oxygen (1.5 wt%) and SiO₂ under 1.0–5.0 GPa between 1000° and 1350°C did not give Si₂ON₂ phase, but yielded a mixture of α,β-Si₃N₄, quartz, and coesite (a high-pressure form of SiO₂). The formation of Si₂ON₂ from oxidized amorphous Si₃N₄ seemed to be assisted by formation of a Si–O–N melt in the system that was enhanced under the high pressure.     

TiO2/MS(M=Cd,Zn,Cu)纳米复合光催化剂的制备及光催化活性研究

在室温下,以正丁胺为模板剂[1],通过简单的化学方法合成ZnS,CdS,CuS纳米颗粒.以钛酸丁酯为主要原料,用溶胶-凝胶法制备了TiO2/ZnS,TiO2/CdS,TiO2/CuS的纳米复合物,采用UV-Vis对其进行简单表征.并通过测定甲基橙的脱色速率,评价所有样品的光催化活性.结果表明:不同的硫化物在同一复合量时...     

In2O3/CdS复合物的制备及光催化性能

以氧化铟(In_2O_3)纳米球作为基体,采用水热法制备了氧化铟/硫化镉(In_2O_3/CdS)复合光催化剂,并利用XRD、SEM等对所制备复合光催化剂进行了表征。结果表明:复合光催化剂由立方相的In_2O_3纳米球和六方相CdS棒状结构组成,且In_2O_3纳米球附着于CdS棒状结构表面上。光学性能测试和光降解实验发现:所得复合光催化剂与纯In_2O_3和纯CdS相比,不仅光响应范围增加,而且光催化亚甲基蓝(MB)的活性也得到显著改善。当In_2O_3/CdS中n(In_2O_3)∶n(CdS)=1∶4时,光催化效率改善尤为明显,当复合催化剂的质量为0.05 g时,MB转化率达到96.2%;这可能是由于CdS接受In_2O_3表面上的光生电子,减少了光生电子与空穴的复合机会,因而提高了光催化降解能力。     

可见光响应的铁掺杂二氧化钛的制备及其光催化性能研究

以硝酸铁、硫酸氧钛为出发原料,通过直接化学法合成了锐钛矿型的Fe掺杂的Ti O2纳米光催化剂;通过X射线衍射仪、傅里叶红外光谱仪、紫外-可见-近红外分光光度计、热差热重分析仪对样品的结构以及性能进行了表征。结果表明:Fe掺杂的纳米Ti O2光催化剂的紫外吸收光谱和纯Ti O2相比,吸收带边发生红移,光响应范围拓展到在可见光区域;Fe的掺杂可以提高Ti O2的光催化性能,其中1%的Fe-Ti O2对亚甲基蓝的光催化活性最高。在模拟可见光条件下,Fe-Ti O2表现出了较优的光催化性能,光照10 min后,降解率高达83.9%。     

钨酸铋-腈纶复合纤维制备及其光催化性能研究

利用湿法纺丝制备了一种易分离、易回收、具有可见光催化性能的钨酸铋-腈纶复合纤维,通过SEM、XRD等分析工具对制备的合成纤维进行表征,探讨其制备反应温度、升温梯度、光照时间等因素对光催化降解亚甲基蓝的影响。研究结果表明:反应温度为150℃,升温梯度为1℃/min时,钨酸铋-腈纶复合纤维具有良好的光催化效果,6.5 h对亚甲基蓝水溶液的降解率能达到83.56%。     

Ag-TiO_2光催化剂的直接化学合成及光催化性能研究

在醇水溶液体系中采用直接化学合成了Ag-TiO_2光催化剂,利用X射线衍射、红外光谱、氮气吸附-脱附和UV-Vis等方法对样品的结构及光学性能进行了表征。结果表明:Ag-TiO_2光催化剂为锐钛矿相TiO_2,Ag的掺杂不改变TiO_2的晶相并可以细化晶粒,晶粒尺寸平均约为10 nm,并可以扩展其可见光响应范围;Ag-TiO_2光催化剂为介孔结构,比表面积为248 m2/g,平均孔直径为7 nm;0.5%的Ag-TiO_2为最佳光催化剂,相比较TiO_2样品,其降解性能提高了135%,光催化性能提高了127%。     

Photocatalytic Properties and Electronic Structure of a Novel Series of Solid Photocatalysts, Bi2 RNbO7 (R = Y, Rare Earth)

The observation of photocatalytic properties and the electronic structure of a new series of rare earth photocatalysts, BiRNbO₇ (R = Y, rare earth), are reported for the firstly time. Polycrystalline samples of BiRNbO₇ were synthesized by a solid-state reaction and characterized by XRD and SEM-EDX. H₂ was evolved from pure water under UV irradiation on the BiRNbO₇ photocatalysts. The variation of ion radius r _R ³⁺ of R in Bi₂ RNbO₇ led to a change in the band structure and photocatalytic activity. The photocatalytic activity A _R ³⁺ decreased with increasing r _R ³⁺.     

氧氮化铝陶瓷的合成与应用

介绍了氧氨化铝的基本性能、合成研究的最新进展、烧结及其抗氧化性、热稳定性和应用。     

类竹节状氮掺杂碳纳米管的制备及性能的研究

本文以三聚氰胺（C3N6H6）为原料,通过高温热分解法成功的制备了氮掺杂碳纳米管（N—CNTs）。据SEM和TEM图像显示,所制备的N—CNTs呈竹节状,并且直径和壁厚统一。利用FTIR图谱分析了N—CNTs的结构和官能团组成。同时,对N—CNTs的发光特性进行了研究,发现样品在蓝紫光范围内具有发光特性,这使得其在光学纳米器件方面具有潜在的应用价值。     

Synthesis of N and S Co-doped TiO2 Nanotubes for Advanced Photocatalytic Degradation of Volatile Organic Compounds (VOCs) in Gas Phase

Topics in Catalysis - In this study, sol–gel combining with hydrothermal methods were successfully used to synthesize N and S co-doped TiO2 nanotubes (N@S-TiO2 NTT) for efficient...     

Copper(II) azide complexes of [Cu(acac)(N3)(dpyam)] and [Cu(μ-N3-κN1)(C2N3-κN1)(dpyam)]2: Synthesis,crystal structure and magnetism

Two new compounds, [Cu(acac)(N₃)(dpyam)] (1), (acac = acetylacetonate; dpyam = di-2-pyridylamine) and [Cu(μ-N₃-κ^N1)(C₂N₃- κ^N1) (dpyam)]₂ (2), have been synthesized and characterized by single-crystal X-ray diffraction and magnetic analyses. Compound 1 is a mononuclear compound in which each of two independent Cu(II) ions is penta-coordinated with a distorted square pyramidal geometry with distortion parameters τ = 0.21 and 0.16. In contrast, compound 2 is an azido-bridged dinuclear compound with monodentate dicyanamide anions and the Cu(II) ions display a distorted trigonal bipyramidal geometry with τ = 0.73 and end-on azido bridges providing an equatorial–axial position between the metal ions. The EPR spectra of powdered samples for 1 and 2 have also been investigated. Magnetic susceptibility measurements of compound 2 reveal a very weak ferromagnetic interaction between the Cu(II) ions with a J value of +5.8 cm⁻¹.     

Preparation,Characterization, and Anticorrosive Properties of Polyaniline Nanotubes

Self-assembled polyaniline nanotubes were synthesized using sodium dodecylbenzene sulfonate both as dopant and soft template by the oxidative polymerization of aniline. Electrical conductivity, electrochemical behavior, and solubility of polyaniline nanotubes were investigated and compared with that of conventional polyaniline synthesized similarly. Polyaniline nanotubes showed enhanced electrical, electrochemical, and solubility properties. Emeraldine base nanotube coating exhibited superior anticorrosion effect, especially in NaCl (3.5%w/w) solution. According to the results of Tafel slope analysis, the corrosion current of iron coupons coated with polyaniline nanotubes was much lower than that of coupons coated with conventional polyaniline in all studied corrosive environments.     

多孔普鲁士蓝类似物的合成及电催化析氧性能

采用一种简单易行的共沉淀法合成了前驱体镍铁普鲁士蓝类似物NiFe-PBA（NF）,然后通过溶剂热处理获得了镍铁普鲁士蓝纳米多孔材料（NFP）。通过XRD、SEM、TEM、XPS、BET及电化学方法对所得材料进行了结构表征和析氧性能测试。结果表明,NFP相对于前驱体NF,电化学比表面积增大、催化活性位点增多,电催化析氧反应（OER）性能显著提高。在浓度1 mol/L KOH水溶液中,达到10 mA/cm2电流密度时,NFP所需过电位仅为260 mV,比NF（320 mV）前驱体低18.75%,也优于大多数已报道的非贵金属催化剂和商用贵金属催化剂,显示出良好的应用前景。     

适用于室内空气净化的规整光催化剂的制备及性能

用酚醛树脂作前驱物,通过炭化方法在预先成形的金属网上直接制备了炭化物载体,并在其上负载TiO2,经烧结后成为规整型光催化剂。利用XRD、SEM技术对载体和催化剂样品进行了表征。考察了催化剂对气相中苯的光催化降解活性,同时还考察了载体制备过程中炭化温度和炭化时间对负载型规整催化剂活性的影响。结果表明,炭化物载体是一种无定型炭,有发达的复合孔隙结构。负载后的规整光催化剂有明显的光催化效果,气相中苯的初始质量浓度为300 mg/m3时,在规整光催化剂存在下,紫外光照100 min后苯质量浓度下降到约20 mg/m3。此外,确定了载体适宜的炭化温度为550~600℃、炭化时间为2 h。规整催化剂避免了粉体催化剂在处理气相系统中产生的粉尘污染,可望用于室内空气的治理。     

环氧化丁腈橡胶/羧基化碳纳米管复合材料的制备与性能研究

采用无溶剂反应性加工技术,以叔丁基过氧化氢为氧化剂、三氧化钼为催化剂,在哈克转矩流变仪中实施了原位催化环氧化反应。产物的全反射红外光谱证实了环氧化丁腈橡胶的生成,用化学滴定法测定了其环氧化度为3.6%;将环氧化丁腈橡胶与羧基化多壁碳纳米管(MWNT-COOH)直接共混制备复合材料,研究了MWNT-COOH对复合材料的硫化性能、动态力学性能、热性能的影响。结果表明,复合材料在150℃～190℃范围内表现出较好的硫化性能,MWNT-COOH含量提高可促进橡胶的交联;复合材料在温度低于Tg时,MWNT-COOH可显著提高材料的储能模量;复合材料的热稳定性能随MWNT-COOH用量的增加而提高,其中4份用量的MWNT-COOH可使环氧化丁腈橡胶的最大热失重速率温度由465℃提高到471℃。     

Synthesis and Photocatalytic Properties of HTaWO<Subscript>6</Subscript> Intercalated with Oxide Materials

Transition metal oxides (TiO₂, MnO₂, Cr₂O₃, Fe₂O₃, NiO, CuO) were intercalated into the interlayer of HTaWO₆ by (1) hydrothermal reaction on HTaWO₆ with 1 M soluble metal nitrate aqueous solution at 130C for 12 h followed by calcination at 250C for 3 h and (2) sol reaction on HTaWO₆/n-C₃H₇NH₂ precursor with metal oxide sol, followed by UV irradiation. The gallery height of transition metal oxide in the interlayer of HTaWO₆ is changed from 0.42 to 0.71 nm, the band gap energies of intercalated materials are less than 3 eV. HTaWO₆/Cr₂O₃, HTaWO₆/MnO, HTaWO₆/Fe₂O₃, HTaWO₆/NiO and HTaWO₆/CuO porous materials are capable of photocatalytic decomposing methyl orange, and the photocatalytic activity of HTaWO₆/TiO₂ is superior to that of unsupported TiO₂.     

SiO2/g-C3N4复合粉体制备及其光催化性能

以St?ber法制备出的二氧化硅(SiO2)微球和三聚氰胺为原料,两者按一定质量比混合后得到前驱体,通过煅烧该前驱体可成功获得SiO2/g-C3 N4复合粉体.利用XRD、SEM、UV-Vis和BET等表征手段对获得的复合粉体进行物相组成、形貌、可见光吸收性能以及比表面积大小等进行分析和测试.结果表明,改进的St?be...     

CeO_2-CdS/埃洛石纳米管的制备及可见光催化性能

采用微波辐射法制备埃洛石纳米管(HNTs)负载CeO_2-CdS复合材料CeO_2-CdS/HNTs。用X射线衍射、透射电子显微镜、紫外-可见漫反射光谱、Fourier变换红外光谱等对CeO_2-CdS/HNTs样品结构和形貌进行表征,考察了可见光下降解亚甲基蓝的光催化活性,讨论了CeO_2/CdS摩尔比对光催化剂活性的影响。结果表明:纳米颗粒CeO_2、CdS以紧密结合的形式牢固的负载在HNTs表面,二者具有协同催化作用。当CeO_2/CdS摩尔比为3:7时,80 min内亚甲基蓝的降解率可达95%。     

合成工艺对氮化硼纳米管显微结构和性能的影响

采用无定型B粉为原料,在催化剂Fe2O3和CaO辅助作用下,控制反应气氛氨气的流量(150~200 mL/min),在1200℃下于真空管式炉中保温4 h,制备氮化硼纳米管(BNNTs)。采用透射电子显微镜(TEM)、X射线衍射(XRD)和傅里叶转换红外光谱分析(FTIR)等手段对产物的结构和形貌进行了表征,结果表明:所得产物为竹节状氮化硼纳米管(BNNTs),其晶体结构为六方氮化硼,外径约为35~100 nm,长度为数微米至数十微米。