贵金属纳米材料生物还原制备技术的研究进展

综述了国内外利用生物还原技术制备贵金属纳米材料及贵金属催化剂的研究进展,并展望了该研究领域的发展方向.     

纳米Fe_3O_4微晶电磁波吸收性能的神经网络研究

应用基于人工神经网络的计算机模拟的方法 ,研究了粒度在 10 nm和 10 0 nm之间的多种 Fe3O4纳米材料分别在 ( a) 1～ 10 0 0 MHz和 ( b) 10 0 0～ 10 0 0 0 MHz频率范围内的电磁波吸收效能 .结果表明 ,在频率范围 ( a)内 ,平均粒度小的 Fe3O4磁导率虚部 μ"(即磁损耗 )大于平均粒度大的 Fe3O4的 μ",且 Fe3O4对电磁波的吸收能力逐渐增强 ,这与实验结果吻合良好 ;根据频率范围 ( a)的所得结果 ,利用人工神经网络 ,预测了在频率范围 ( b)内可能出现的情况 .文中就其物理本质也作了简单的分析和探讨     

多步沉淀法制备纳米无机复合抗菌粉体

目的研究一种以银、钛和锡为组分的新型纳米无机复合抗菌粉体的制备工艺。方法采用多步沉淀法,并通过单因素实验和正交实验确定最优工艺条件。结果最终产品的基本化学组成式为Ag0.03Sn0.16Ti0.35P0.11O0.34;产率达95.5%;粉体平均粒径50 nm;无外加光照、粉体浓度80mg/L时,30 min内其对大肠杆菌、金黄色葡萄球菌和白色念珠菌的抗菌率均达100%;粉体颜色浅,耐候性好。结论该方法制备的粉体具有较强的广谱抗菌效果,解决了银系抗菌剂易变色、对真菌作用效果不佳及钛系抗菌剂必须有光照才能起作用等问题。     

水热法制备二氧化锡纳米材料实验的改进

针对“水热法制备二氧化锡纳米材料”实验教学中存在的问题进行了改进.利用平行反应仪代替传统的水热反应釜,在反应条件明确、可控的同时提高了实验效率;将透射电子显微镜等大型分析仪器引入实验中对实验产品进行表征,让学生在更加直观地了解纳米材料的形貌与结构的同时自行设计和优化实验环节,培养和提高了学生的基本操作技能、创新意识及综合实践能力,取得了良好的教学效果.     

空心纳米SiO_2为涂层的整体式催化剂的制备及催化性能

整体式催化剂能够解决纳米级催化剂在固定床加氢反应器中应用的缺陷,并进一步提高催化剂的催化性能。采用多次浸涂法制备了以Pd基蛋壳型SiO2纳米催化剂为涂层,铝溶胶为无机粘合剂、堇青石为结构化基体的整体式催化剂,并进一步研究了该整体式催化剂对乙炔选择性加氢反应的催化性能。研究结果表明:该整体式催化剂具有较高的比表面积和宏观的孔道结构,提高了活性组分的分散性并降低了气体的扩散阻力,在乙炔转化率接近100%时,乙烯选择性可以达到47.5%;此外,该催化剂良好的机械稳定性能,提高了催化加氢性能的稳定性。     

Compound-fluidic electrospray: An efficient method for the fabrication of microcapsules with multicompartment structure

Microcapsules with multiple compartments are of significant importance in many applications such as smart drug delivery, microreactor, complicated sensor, and so on. Here we report a novel compound-fluidic electrospray method that could fabricate multicompartment microcapsules in a single step. The as-prepared microcapsules have multiple compartments inside. The compartments are separated from each other by inner walls made from shell materials, and different content can be independently loaded in each of them without any contact. We assemble a hierarchical compound nozzle by inserting certain numbers of metallic inner capillaries separately into a blunt metal needle. The particular configuration of the compound nozzle induces a completely and independently envelope of core fluids by shell fluid, as a result of which mulicomponent microcapsules with multicompartment structure can be obtained. And also, the number of inner compartments and the corresponding encapsulated components can be controlled by rationally designing the configuration of the compound nozzle. This general method can be readily extended to many other functional materials, especially for the effective encapsulation of active ingredients, such as sensitive and reactive materials.     

21世纪最有前途的材料Ⅱ——纳米材料的制备与应用

主要介绍了二维纳米薄膜、三维纳米晶体材料和纳米复合材料的制备方法。探讨了各种方法的特点与适用性,并展望了纳米材料在催化、光学、电学、磁学,传感器、陶瓷及生物医学等领域的应用前景。     

Morphological structure and physicochemical properties of nanotube TiO2

Morphological structure and physicochemical properties of nanotube TiO₂ were investigated. It was found that the TiO₂ nanotube consisted of 2–5 monolayers of TiO₂ molecules, and its inner diameter was between 4.2 and 5.9 nm. The nanotube TiO₂ powder had high specific surface area and pore volume (379 m²/g and 1.431 cm³/g respectively) and its decolorization activity for Reactive Brilliant Red X-3B was 2 times higher than that of raw TiO₂ (p-25). This new type of TiO₂ was hopeful for application in photocatalysis and composite nanomaterial.     

多孔阳极氧化铝模板制备金属/合金纳米管的研究进展

阳极氧化铝(AAO)模板具有纳米级的高密度孔阵列,孔直径、长度可调,在一维纳米材料的制备中得到广泛应用。本文介绍了利用AAO模板制备金属/合金纳米管的五种制备方法,并对其优缺点作了相应的概括和评价。     

提升Pd基电催化剂氧还原活性的策略

氧还原反应(ORR)是许多电化学相关技术的核心反应,许多研究致力于制备同时具备高活性、高稳定性和低成本的催化剂.Pd基纳米材料由于其相对较优的催化性能和相对丰富的储量,有望成为Pt的替代品,受到了广泛关注,但要达到商品化程度,其性能需进一步提高.本文以Pd基催化剂应用于ORR电催化为背景,综述了近年来Pd基催化剂ORR...