基于稀土离子介导石墨烯量子点荧光开关的凝血酶生物传感器

稀土离子(Er3+)可与荧光石墨烯量子点(GQDs)表面的含氧基团发生配位,在Er3+介导下形成高配位数的GQDs/Er3+配合物,引起GQDs聚集而使其荧光减弱.凝血酶(Tb)中的氮和氧等原子可与Er3+发生配位作用,从而与GQDs竞争结合Er3+,减弱了GQDs与Er3+的作用而使其荧光恢复.通过检测GQDs的荧光即可实现对Tb活性的高灵敏分析,构建了基于Er3+介导GQDs荧光开关的Tb传感方法,采用透射电镜、原子力显微镜、红外吸收光谱以及荧光光谱等对传感机理进行了研究.本方法对Tb的检出限低至0.049 nmol/L,其它蛋白质对Tb检测无明显干扰,实际样品中Tb加标回收率为98.0%~105.3%,相对标准偏差为0.6%~4.2%.     

Fiber-reinforced three-dimensional graphene aerogels for electrically conductive epoxy composites with enhanced mechanical properties

To enhance the mechanical properties of three-dimensional graphene aerogels with aramid fibers,graphene/organic fiber aerogels are prepared by chemical reduction of graphene oxide in the presence of organic fibers of poly(p-phenylene terephthalamide)(PPTA) and followed by freeze-drying. Thermal annealing of the composite aerogels at 1300 ° C is adopted not only to restore the conductivity of the reduced graphene oxide component but also to convert the insulating PPTA organic fibers to conductive carbon fibers by the carbonization. The resultant graphene/carbon fiber aerogels(GCFAs) exhibit high electrical conductivities and enhanced compressive properties, which are highly efficient in improving both mechanical and electrical performances of epoxy composites. Compared to those of neat epoxy, the compressive modulus, compressive strength and energy absorption of the electrically conductive GCFA/epoxy composite are significantly increased by 60%, 59% and 131%, respectively.     

Mechanically Strong Janus Poly(N-isopropylacrylamide)/Graphene Oxide Hydrogels as Thermo-responsive Soft Robots

Simple preparation of stimuli-responsive hydrogels with good mechanical properties and mild stimuliresponsiveness is essential for their applications as smart soft robots.Mechanically strong Janus poly(Nisopropylacrylamide)/graphene oxide (PNIPAM/GO) nanocomposite hydrogels with stimuli-responsive bending behaviors are prepared through a simple one-step method by using molds made of a Teflon plate and a glass plate.Residual oxygen in the air bubbles on the Teflon plate surface affects the polymerization and hence the cross-linking density,leading to the different swelling/deswelling rates of the two sides of the gels.Therefore,the hydrogels exhibit bending/unbending behaviors upon heating/cooling in water.The incorporation of GO nanosheets dramatically enhances the mechanical properties of Janus hydrogels.Meanwhile,the photo-responsive property of the GO nanosheets also imparts the hydrogels with remotecontrollable deformation under IR irradiation.The application of the Janus PNIPAM/GO hydrogels as thermo-responsive grippers is demonstrated.     

镁热还原CO2气体制备介孔石墨烯及其电容特性研究

以CO_2为原料,采用金属镁热还原法,制备出富含介孔结构的石墨烯材料。分别利用X射线衍射、扫描电镜、透射电镜、拉曼光谱和N_2吸附-脱附等测试手段对材料的微观结构进行了表征。通过在镁粉中加入不同质量的MgO,可以实现对石墨烯形貌和孔结构的调控,当MgO/Mg质量比为8∶1时,产物(MRG-8)具有均一的介孔结构(4nm)。并对材料的电化学性能进行了测试,在1mol/L KOH的电解液中,MRG-8具有最高的比电容(171F/g),同时具有非常好的倍率特性,循环测试12000周,比电容保持率为94%。当采用[EMIM][BF4]离子液体作为电解液,以MRG-8为电极材料组装成的对称型超级电容器显示出超高功率密度(175k W/kg),对应的能量密度为28.1Wh/kg。因此,采用此方法制备的介孔石墨烯材料在高功率的超级电容器领域具有潜在的应用前景。     

石墨烯导热性能及其测试方法

石墨烯以其独特的结构和优异的性能引起人们广泛的关注。本文通过总结近期国内外石墨烯导热工作研究进展,梳理了石墨烯的导热机理,根据导热机理指出缺陷、基底、石墨烯边缘是影响石墨烯热导率的主要因素。综述了采用分子动力学及非平衡态格林函数方法进行石墨烯热导率模型计算的研究成果,并在模型的基础上,全面阐述了实验方面针对不同层数石墨烯热导率的测试方法及结果。     

石墨烯基复合材料去除和检测重金属离子的研究进展

石墨烯具有超大的比表面积、较快的载流子迁移速率和优异的电催化活性,广泛用于环境保护与检测领域。过去几年,基于石墨烯的大批高效吸附剂和传感器均被开发并应用于重金属离子的污染治理。本文详细阐述了石墨烯基复合材料在重金属离子去除和检测方面的研究进展,同时比较了不同方法的优缺点,最后对后续研究方向进行了展望。     

微波调控石墨烯-碳纳米管协同增强聚氨酯损伤自修复研究

首先采用溶液共混法制备出石墨烯-碳纳米管(G-CNT)/聚氨酯(TPU)复合材料,然后通过拉伸实验及扫描电子显微镜(SEM)表征来考察该材料的拉伸强度和微波自修复特性,并从力学及材料与微波之间的相互作用等角度对其拉伸强度增强和微波修复机理进行研究.结果表明:在拉伸强度方面,与单一的石墨烯或CNT增强TPU相比,G-CNT之间形成的协同效应使TPU拉伸强度得到进一步提高,当石墨烯和CNT的质量比为3∶1时,G-CNT/TPU抗拉强度较纯TPU提高了67%,较G/TPU提高了18%,较CNT/TPU提高了25%;在材料裂纹的微波修复方面,石墨烯和CNT之间的协同效应使TPU材料自修复效果得到有效提高,当石墨烯和CNT的质量比为3∶1时,G-CNT/TPU修复效果达到最高值117%.     

SnS2纳米花/石墨烯纳米复合物的一步法合成及其增强的锂离子存储性能

SnS₂ is considered as an attractive anode material to substitute commercial graphite anodes of lithium-ion batteries due to its high specific capacity of 645 mAh·g^-1 as well as low cost. Nevertheless, it suffers poor large volume expansion during the lithiation/delithiation processes, leading to the loss of electrical contact and rapid capacity fading. Herein, by using a facile one-step solvothermal method, SnS₂ nanoflower/graphene nanocomposites (SnS₂ NF/GNs) were prepared, where flower-like SnS₂ hierarchical nanostructures consisting of ultrathin nanoplates, are tightly enwrapped in graphene nanosheets. As anode materials for lithium-ion batteries, the SnS₂ NF/GNs electrode exhibit superior electrochemical performance, with a reversible capacity of 523 mAh·g^-1 after 200 charge-discharge cycles. The enhanced Li storage performance was attributed to the synergistic effect of SnS₂ and graphene. The SnS₂ NF can effectively accommodate the volume change and shorten Li⁺ diffusion distance, while graphene nanosheets can further alleviate the volume expansion of SnS₂ and improve the electronic conductivity.     

Layer Dependence of Graphene for Oxidation Resistance of Cu Surface

We studied the oxidation resistance of graphene-coated Cu surface and its layer dependence by directly growing monolayer graphene with different multilayer structures coexisted, di-minishing the influence induced by residue and transfer technology. It is found that the Cu surface coated with the monolayer graphene demonstrate tremendous difference in oxidation pattern and oxidation rate, compared to that coated with the bilayer graphene, which is considered to be originated from the strain-induced linear oxidation channel in monolayer graphene and the intersection of easily-oxidized directions in each layer of bilayer graphene, respectively. We reveal that the defects on the graphene basal plane but not the boundaries are the main oxidation channel for Cu surface under graphene protection. Our finding indi-cates that compared to putting forth efforts to improve the quality of monolayer graphene by reducing defects, depositing multilayer graphene directly on metal is a simple and effective way to enhance the oxidation resistance of graphene-coated metals.     

Micro-droplet Trapping and Manipulation: Understanding Aerosol Better for a Healthier Environment

Understanding the physicochemical properties and heterogeneous processes of aerosols is key not only to elucidate the impacts of aerosols on the atmosphere and humans but also to exploit their further applications, especially for a healthier environment. Experiments that allow for spatially control of single aerosol particles and investigations on the fundamental properties and heterogeneous chemistry at the single-particle level have flourished during the last few decades, and significant breakthroughs in recent years promise better control and novel applications aimed at resolving key issues in aerosol science. Here we propose graphene oxide (GO) aerosols as prototype aerosols containing polycyclic aromatic hydrocarbons, and GO can behave as two-dimensional surfactants which could modify the interfacial properties of aerosols. We describe the techniques of trapping single particles and furthermore the current status of the optical spectroscopy and chemistry of GO. The current applications of these single-particle trapping techniques are summarized and interesting future applications of GO aerosols are discussed.