一步法制备铁氧化物/氮改性氧化石墨/碳纳米管异质结及其用于催化活化过一硫酸氢钾降解亚甲基蓝模型染料（英文）

随着较差的生物相容性和更高毒性有机染料的应用,如酚类化合物和抗生素,水污染和食品污染变得极其严重.这不仅危害人类健康,而且严重污染自然环境.过硫酸盐去污技术利用自由基活化降解过程,成为处理一系列污染物非常有效的方法;然而设计具有多功能性的高性能催化剂仍然面临着巨大的挑战.因此,本文借鉴铁基材料、氮改性石墨和碳纳米管独特的物化性质,以尿素、铁盐、氧化石墨、碳纳米管为原材料,通过一步水热法成功制备了三维多功能铁氧化物/氮改性氧化石墨/碳纳米管异质结,用作活化过一硫酸氢钾复合盐以降解有机模型污染物亚甲基甲蓝(MB),研究了高级氧化法(AOPs)作用机理和优化反应条件.XRD、红外光谱、SEM和XPS结果表明,铁氧化物通过物理静电作用力和化学键结合力已经被牢牢固定在了氮修饰的氧化石墨结构框架内.当加入了碳纳米管之后,它会与石墨形成类似于互穿聚合物网络的结构,从而具有三维材料的优点,且提升电子转移电导率,使得催化剂的结构和性能有了很大的改善.此外,优化了降解系统、PMS负载量、初始有机污染物浓度和催化剂用量等因素.结果表明,处于催化剂/PMS系统时,亚甲基蓝可以在12min之内有效地完全降解,可归结于碳、氮以及主要活性物质铁氧化物之间的协同作用.基于数据拟合分析,污染物氧化降解系统与拟一阶动力学相符合,其速率常数约为0.33 min~(-1).淬灭实验证明,硫酸根自由基和羟基自由基是主要的反应活性物种.这种同时富含铁/氮分级的多孔碳骨架异质结物质不仅可用作过渡金属催化剂,而且为制备其他异质结提供参考,以用于超级电容器、储能材料、电催化剂等领域     

Hydrogenated Bismuth Molybdate Nanoframe for Efficient Sunlight‐Driven Nitrogen Fixation from Air

Sunlight‐driven dinitrogen fixation can lead to a novel concept for the production of ammonia under mild conditions. However, the efficient artificial photosynthesis of ammonia from ordinary air (instead of high pure N₂) has never been implemented. Here, we report for the first time the intrinsic catalytic activity of Bi₂MoO₆ catalyst for direct ammonia synthesis under light irradiation. The edge‐exposed coordinatively unsaturated Mo atoms in an Mo?O coordination polyhedron can act as activation centers to achieve the chemisorption, activation, and photoreduction of dinitrogen efficiently. Using that insight as a starting point, through rational structure and defect engineering, the optimized Bi₂MoO₆ sunlight‐driven nitrogen fixation system, which simultaneously possesses robust nitrogen activation ability, excellent light‐harvesting performance, and efficient charge transmission was successfully constructed. As a surprising achievement, this photocatalytic system demonstrated for the first time ultra‐efficient (1.3 mmol g^?1 h^?1) and stable sunlight‐driven nitrogen fixation from air in the absence of any organic scavengers.     

Adsorption equilibrium,kinetics and mechanism of Pb(II) over carbon–silica composite biosorbent with designed surface oxygen groups

Research on Chemical Intermediates - Heavy metal contamination, especially contamination involving Pb(II), is a major environmental problem faced by modern society; hence, research on...     

Carbon–silica composite bio-sorbents with a high density of oxygen-containing sites for efficient methylene blue adsorption

Research on Chemical Intermediates - There is a growing trend to employ agricultural waste/by-products (AWBs) as substrates for the development of dye bio-sorbents, and surface modification plays a...     

具有垂直各向异性(Pt/Co)n/FeMn多层膜的交换偏置

采用磁控溅射方法制备了以Pt为缓冲层和保护层的具有垂直各向异性(Pt/Co)_n/ FeMn多层膜.研究结果表明，多层膜的垂直交换偏置场H_ex和反铁磁层厚度的关 系与其具有平面各向异性的交换偏置场随反铁磁层厚度变化趋势相近.随着铁磁层调制周期 数的增加，垂直交换偏置场H_ex相应减小，并且与铁磁层的调制周期数近似成反 比关系.(Pt/Co)₃/FeMn的垂直交换偏置场H_ex已经达到22.3kA/m.为 关键词： 交换偏置 垂直各向异性 多层膜     

取样光纤布拉格光栅

用传输矩阵法从理论上计算了取样光纤布拉格光栅的反射谱特性,提出了几种最高其谱特性的调制方案。用取样掩模版一次成栅的方法首次获得了波长间隔为０．８ｎｍ和１．６ｎｍ的取样光纤布拉格光栅。     

浅析图论教学

图论是《离散数学》课程的重要组成部分,也是数学专业高年级的选修课程.本文介绍了从事图论教学和研究的一些心得,探讨了如何在该课程的教学过程中激发学生的学习兴趣和培养学生的发现问题及解决问题能力,从而为学生今后作毕业论文或者进一步从事科学研究打下基础.