足球状CdS微米球的合成与发光性能的初步研究

应用化学水浴沉淀法，合成了具有特殊形貌的由纳米颗粒组成的Cds微米球，通过改变反应温度实现了对产物尺寸的控制．XRD测试结果表明生成产物为结晶良好的六角结构CdS，PL谱测试说明了产物有较好的光致发光性能．利用TEM，SAED，FEG-SEM和紫外吸收谱分析等测试手段对其结构和形成机理进行了研究．     

PEG辅助氧化锌纳米棒的水热法制备

采用PEG辅助水热法合成了ZnO纳米棒，XRD显示产物为结晶良好的六角结构晶体ZnO，PL谱表明适当退火处理后产物有较好的光致发光性能．利用TEM和SAED研究了纳米棒的形貌和生长机制，并研究了氢氧化钠浓度和反应时间对产物形态和尺寸的影响．     

载气气氛对Co/MgMoO4催化剂CVD法高效合成碳纳米材料的影响

High yield and quality mutli-walled carbon nanotube (MWNT) bundles and carbon nanofibers were synthesized by catalytic decomposition of methane over Co/MgMoO₄ catalyst at 1 000 ℃. TEM studies showed that the products were mainly carbon nanofibers without carrier gas and were all MWNT bundles with hydrogen or nitrogen as carrier gas. Thermal gravimetric analyses (TGA) on the raw product indicated that the purity of MWNT was higher than 95wt%. The growth mechanism of carbon nanofibers and MWNTs was also discussed.     

竖直浮动催化CVD法合成毫米级定向纳米碳纤维束

碳纳米管[1]和纳米碳纤维[2]的合成和应用是当前一维碳纳米材料理论和实验研究的焦点[3]。定向排列的碳纳米材料由于具有特殊的组织和性能[4~6],具有广泛的应用前景,例如,它可以作为优异的电子发射源,用于制作平板显示器等[6]。所有合成一维碳纳米材料的方法中[1,4,7],只有化学     

水热条件下坡缕石在NaOH溶液中的行为及结构变化

分别用1,2和3 mol·L^-1的NaOH溶液,在不同的温度条件下对坡缕石进行了侵蚀实验。对反应后的固相产物进行了XRD和SEM分析,对浸出液中的金属阳离子进行了原子吸收光谱分析。讨论了反应温度和碱溶液浓度对碱溶后产物的影响。XRD和SEM结果表明,c_NaOH≤2 mol·L^-1时,坡缕石经碱溶液侵蚀后,可以生成蒙脱石和方沸石,其中反应温度的升高有利于方沸石的形成,碱溶液浓度的升高有利于蒙脱石的形成。当碱溶液浓度达到3 mol·L^-1,反应温度为200 ℃时,最终产物为SiO₂。浸出液的定量分析结果显示,坡缕石与碱溶液的反应过程中,Na⁺对八面体阳离子的置换具有选择性,置换顺序为：Al³⁺＞Fe³⁺(Fe²⁺)＞Mg²⁺。     

化学气相沉积合成碳包裹镍纳米晶的初步研究

Nickel nanocrystals encapsulated in carbon shells were prepared by the large body knowledge developed for the growth of carbon nanotubes (CNTs), i.e. chemical vapor deposition. The products were characterized by transmission electron microscopy, XRD and FTIR. The results showed that the oxidization of CNT surface made it possible to interreact with nickel ions in solution. Ni-impregnated CNTs transformed into monocrystalline nickel nanoparticles supported on CNTs at 600 ℃ in nitrogen atmosphere. Subsequently, they would be covered with graphene layers during reaction with acetylene at 600 ℃. The formation mechanism has been preliminarily discussed on experimental results.     

镧掺杂对大洋锰结核制备铁氧体磁性的影响

大洋锰结核又称铁锰结核、多金属结核,常见于4 000～6 000 m的海底沉积物表层,在世界各大洋底均有分布,预计总储量超过3×1012 t[1].天然锰结核含有Mn和Fe,以及Cu、Co、Ni、铂族和稀土等60多种金属元素,其中锰占20%～30%,铁约占3～20%[2].从化学成分而言,大洋锰结核与Mn-铁氧体(铁酸锰)十分接近.以锰结核为原料合成Mn-铁氧体可以为这种天然资源的开发利用提供新思路.     

纳米CaCO3负载过渡金属CVD法制备多壁碳纳米管的研究

以纳米碳酸钙粉体为载体,用浸渍法制备了可用于化学气相沉积(CVD)法制备碳纳米管的高产率催化剂.应用FESEM,HRTEM,TEM,XRD和激光拉曼谱对产物进行了表征.结果表明,由于纳米碳酸钙具有较大的比表面积,可高密度地承载催化剂活性组分.在碳纳米管生长初期,处于缓慢分解状态的纳米碳酸钙才能有效地起到载体作用,且反应温度为700～750℃时,碳纳米管的产率较高.Fe-Co双金属催化剂在700℃,催化生长60min后,可增重10倍,而且产物中无定形碳含量极少.纳米碳酸钙载体易于提纯,用质量分数为30%的硝酸超声提纯粗产品1h,可使纯度提高到97%,且不破坏碳纳米管结构.     

化学溶液沉积法制备单分散氧化锌纳米棒阵列

在由溶胶凝胶法制备的纳米ZnO薄膜基底上, 采用化学溶液沉积法制备了单分散、高度取向的ZnO纳米棒阵列膜. 通过控制纳米ZnO薄膜的制备工艺, 可以调节氧化锌纳米棒的直径. 利用FESEM, TEM, HRTEM, SAED和XRD表征了氧化锌纳米棒阵列的形貌和晶体结构. ZnO纳米棒的室温PL谱具有很高的紫外带边发射峰, 在可见光波段无发射峰, 表明该方法制备的ZnO纳米棒晶体结构完整, 晶体中O空位的浓度很低.     

多壁碳纳米管包裹Fe3C单晶纳米线的初步研究

Multi-walled carbon nanotubes were fabricated by chemical vapor deposition with acetylene as carbon source and titanate modified palygorskite as catalyst at high temperature. A part of as-grown nanotubes was partially filled with foreign material in the shape of nanowire by transmission electron microscopy (TEM) observations. The en-capsulated nanowires was single crystalline iron carbide upon selected area electron diffraction(SAED)patterns and X-ray energy dispersive spectrum (EDS) results. Thermal gravimetric analyses (TGA) on the as-grown samples indicated that the yield of carbon nanotubes was largest at 750℃ and the content of amorphous carbon decreased with increasing temperature. Furthermore， the growth mechanism was discussed on the experimental results in the paper.