ZnIn2S4/Au纳米片阵列的制备及其可见光响应光电化学固氮特性

采用简单的水热法合成出单晶ZnIn₂S₄纳米片阵列以实现可见光响应光电化学固氮。并采用光沉积法将超细Au纳米颗粒（5 nm）沉积于ZnIn₂S₄纳米片的棱角位置处,实现了可见光俘获和载流子分离能力的同时增强。当负载合适含量的Au纳米颗粒,ZnIn₂S₄纳米片阵列的光电固氮活性由1.092 μg·cm^-2·h^-1提升至2.262 μg·cm^-2·h^-1。我们还提出一个简单模型用以阐明其性能增强机制,这也被光致发光（PL）谱和光电化学（PEC）性能结果所证实。     

柠檬酸辅助水热法制备可见光高效去除甲基橙的Bi2WO6纳米片

以Bi(NO3)3·5H2O和Na2WO3 ·2H2O为原料,以柠檬酸为络合剂,采用辅助水热法制备了Bi2WO6纳米片,运用X射线衍射、扫描电镜、场发射高分辨透射电镜、拉曼光谱、红外光谱和紫外-可见漫反射光谱等手段对样品进行了表征,并考察了该催化剂光催化去除甲基橙反应性能.结果表明,通过调节体系的pH值可制得结晶度良好...     

Cyclodextrin-graphene hybrid nanosheets as enhanced sensing platform for ultrasensitive determination of carbendazim

In this paper, cyclodextrin-graphene hybrid nanosheets (CD-GNs) for the first time have been used as an enhanced material for ultrasensitive detection of carbendazim by electrochemistry method. The peak currents of carbendazim on the GNs modified glassy carbon electrode (GNs/GCE) and the CD-GNs/GCE are increased by 11.7 and 82.0 folds compared to the bare GCE, respectively. This indicates the nanocomposite film not only shows the excellent electrical properties of GNs but also exhibits high supramolecular recognition capability of CDs. At the CD-GNs/GCE, the peak currents increase linearly with the concentration of carbendazim in the range of 5 nM-0.45 μM. The detection limit of carbendazim reached to 2 nM on the basis of the signal-to-noise characteristics (S/N = 3) and the recoveries were between 98.9% and 104.5%. The developed electrochemical sensor exhibited good stability and reproducibility for the detection of carbendazim. And the CD-GNs based electrochemical sensor was also successfully demonstrated for the detection of carbendazim in water sample with satisfactory results. Furthermore, this simple sensing platform can in principle be extended to the detection of other benzimidazole fungicide which can form host-guest complexes with cyclodextrin.     

Non-isothermal crystallization of ethylene-vinyl acetate copolymer containing a high weight fraction of graphene nanosheets and carbon nanotubes

The effect of the different geometrical dimensionality of two dimensional graphene nanosheets(2D GNSs) and one dimensional carbon nanotubes(1D CNTs) on the non-isothermal crystallization of an ethylene-vinyl acetate(EVA) copolymer at high loading(5 wt%) was studied.Transmission electron microscopy indicated a homogeneous dispersion of GNSs and CNTs in EVA obtained by a solution dispersion process.Fourier-transform infrared spectroscopy and differential scanning calorimetry measurements showed that 1D CNTs and 2D GNSs acted as effective nucleating agents,with a noticeably increased onset crystallization temperature of EVA.A high weight fraction of nano-fillers slowed the overall crystallization rate of composites.At the same crystallization temperature,the crystallization behavior of GNS/EVA composites was slowed compared to that of the CNT/EVA ones owing to larger nucleus barrier and activation energy of diffusion.Dynamic mechanical relaxation and rheology behavior of CNT/EVA and GNS/EVA composites demonstrated that the planar structure of the GNSs had an intensively negative effect on EVA chain mobility due to interactions between nanofillers and polymer chains,as well as spatial restriction.     

二硫化钼纳米片修饰聚氨酯海绵及吸油性能研究

以二硫化钼( MoS2)粉末为原料,采用超声辅助液相剥离法制备了MoS2纳米片,通过MoS2纳米片和聚二甲基硅氧烷( PDMS)依次修饰聚氨酯( PU)海绵,制备了疏水亲油性质的PU-MoS2吸油材料,并测试了其接触角和吸油性能。结果表明,所制备的PU-MoS2海绵有着优良的疏水亲油性能和较强的吸油能力。对不同的有机液体,PU-MoS2海绵分别能够吸取自身重量12~86倍的有机溶剂。尺寸较小MoS2纳米片修饰制备的PU-MoS2海绵具有较高的吸油能力。此外,PU-MoS2海绵在重复使用20次后仍能保持强的吸油能力,表明其可循环利用,具有良好的应用前景。     

类石墨烯C3N4纳米片光催化分解水制氢中的量子限域效应

从层状化合物获得的纳米片是一类新型纳米结构材料,这种二维各向异性的纳米甚至亚纳米级的材料具有独特的物理化学性能,其中最好的一个例证就是从石墨烯C₃N₄到石墨烯C₃N₄纳米片的转变。通过高温氧化热刻蚀方法将体相g-C₃N₄剥离成g-C₃N₄纳米片,应用于染料敏化可见光分解水产氢,表现出了较体相g-C₃N₄高于2.6倍的产氢速率。通过X射线衍射（XRD）、傅里叶变换红外（FTIR）光谱、扫描电子显微镜（SEM）、Brunauer-Emmett-Teller（BET）、荧光光谱和光电化学等表征研究了g-C₃N₄纳米片的结构及曙红（EY）和g-C₃N₄纳米片之间的电子迁移过程。热剥离后的g-C₃N₄纳米片具有较高的比表面积,不仅可以更为有效地吸附染料分子,还因其量子限域效应大大增强了光生电荷的分离效率和电子转移效率,改善了电子沿平面方向的传输能力以及光生载流子的寿命,从而显著提高g-C₃N₄纳米片的光催化产氢活性。     

Fe-N共掺杂纳米碳材料的形貌对电化学还原反应的影响

众所周知,石墨烯片（GS）和碳纳米管是能源转化和储存应用中有效的催化剂. 然而,过渡金属基氮（N）掺杂的体系中经常形成GS和碳纳米管的复合物,使得该体系内的构效关系研究变得十分困难. 为了可控制备出含有理想物种的催化剂,作者尝试通过利用氮对碳纳米管生长的效应调节生成产物的形貌. 本文中,作者采用一步法制备了一系列Fe-N共掺杂的GS、GS/竹节碳纳米管(BCNTs)复合物及BCNTs催化剂. 为了评估碳形貌对催化剂性能的影响,作者采用氧气还原反应（ORR）及二氧化碳还原反应（CO₂RR）作为模型反应. 电化学测试结果表明,所有的样品当中仅含BCNTs的催化剂表现出最好的ORR活性（起始电位E_onset = 1.02 V_RHE）及CO₂RR活性（CO生成法拉第效率FE_CO = 91.1%,-0.6 V_RHE）. 进一步的研究表明,优异的活性与独特的BCNTs中存在的缺陷、较大的比表面积、高含量的吡啶N及FeN_x相关. 该工作加深了作者对形貌相关的ORR及CO₂RR过程的认识和理解.     

具有水下超疏油性能的MXene高效油水分离膜

基于二维材料MXene(Ti₃C₂T_x)的化学组成和纳米片状结构, 在不锈钢网上制备了具有MXene微纳结构表面的新型亲水和水下超疏油分离膜. 对于不同类型的油-水混合物, 该膜材料可实现重力驱动的高效油水分离, 收集的水中残油量小于4 mg/L, 具有高分离效率(>99.99%), 水通量高达57.52 L·m^-2·s^-1. 此外, 经高温处理和多种有机溶剂浸泡后MXene膜仍具有高效的油水分离性能, 并表现出优异的稳定性和循环性.     

A novel nano‐cotton‐like bismuth oxyfluoride (NC‐BiOF) and a novel nanosheet heterogeneous compound BiOF@ZIF‐8 as catalyst for the selective and green oxidation of benzylic alcohols

We describe here for the first time a new morphology of BiOF nanoparticles with a cotton‐like structure, made using a hydrothermal synthesis method. We also prepared heterogeneous nanosheets of BiOF@ZIF‐8 by a one‐pot synthesis under hydrothermal conditions. We demonstrate that in this method the morphology of BiOF and one‐pot synthesis conditions are the main factors for the preparation of the nanosheet BiOF@ZIF‐8. Fourier transform infrared (FTIR), X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy‐dispersive X‐ray (EDX), thermogravimetry‐differential thermal analysis (TG‐DTA), and BET surface area were used to characterize the samples prepared. XRD, SEM, and adsorption–desorption analysis showed that the structure of ZIF‐8 and BiOF form intact only in one‐pot synthesis of BiOF (with nano‐cotton‐like morphology) with Zn(NO₃)₃, while spectral techniques show the successful encapsulation of the sheet BiOF on ZIF‐8. Nanosheet BiOF@ZIF‐8 was found to be a highly efficient heterogeneous catalyst for the selective oxidation of alcohols. BiOF@ZIF‐8 could be reused several times although it got less active with recycling.     

氮掺杂TiO2/HTi2NbO7纳米片复合材料的制备及其可见光催化性能

首先采用高温固相法制备层状前驱体CsTi_2NbO_7,通过与硝酸进行质子交换反应可得到层状HTi_2NbO_7,然后将HTi_2NbO_7分散在四丁基氢氧化铵(TBAOH)溶液中进行剥离反应,得到HTi_2NbO_7纳米片悬浮液,并进行冷冻干燥处理。以尿素为N源,将冷冻干燥的HTi_2NbO_7纳米片与TiO_2前驱体(钛酸异丙酯)混合物进行高温焙烧处理,成功地合成了新型氮掺杂Ti O_2/HTi_2NbO_7纳米片(N-TTN)复合材料。采用扫描电子显微镜(SEM)、高倍透射电子显微镜(HRTEM)、X射线衍射(XRD)、N_2吸附-脱附测试、X射线光电子能谱(XPS)、紫外可见吸收光谱(UV-Vis)及电化学测试等对材料的形貌、晶体结构、比表面积、孔分布和光吸收性能等进行表征与分析。研究发现锐钛矿型TiO_2纳米颗粒均匀地分散在HTi_2NbO_7纳米片表面,在两组分间形成异质结结构。通过在可见光下降解有机污染物罗丹明B(RhB)来评价不同样品的光催化活性。结果表明,N-TTN复合材料具有最优的光催化降解活性,活性的增强主要归功于N元素的掺杂、异质结的构筑、增大的比表面积和丰富的介孔结构。