石墨烯/银纳米复合材料的制备及抗菌性能研究

采用改进的Hummers法制备氧化石墨(GO),加入一定量的聚乙烯亚胺和硝酸银(PEI-Ag+)配位复合物,通过自组装法组装,利用硼氢化钠的还原性,制备石墨烯/银纳米复合材料。用紫外可见吸收光谱(UV-Vis)、红外吸收光谱(FT-IR)、X射线衍射(XRD)、循环伏安法(CV)、扫描电镜(SEM)、拉曼光谱(Raman)等手段对所制备的石墨烯/银纳米复合材料进行表征。以金黄色葡萄球菌和大肠杆菌为模型对纳米复合材料的抗菌性能进行研究。结果表明:银纳米粒子负载在石墨烯表面形成石墨烯/银纳米复合物材料,石墨烯/银纳米复合材料对金黄色葡萄球菌和大肠杆菌生长具有较好的抑制作用,且抗菌性能稳定。当石墨烯/银纳米复合材料浓度为4和15 mg/m L时,分别对金黄色葡萄球菌和大肠杆菌的抑菌效果好。     

Gr/NiFe2O4纳米复合材料的制备与形成机理研究

以氧化石墨烯(GO)、Fe2(SO4)3和NiSO4为初始反应物,利用一步水热法合成了Gr/NiFe2O4纳米复合材料。采用X射线衍射(XRD)、透射电子显微镜(TEM)和拉曼光谱(RS)等分析手段对Gr/NiFe2O4样品进行了表征。结果表明:经过水热反应GO被还原的同时,纳米NiFe2O4成功地负载到石墨烯上,二者之间存在较强的界面相互作用,而且NiFe2O4纳米粒子增加了石墨烯片层间的距离避免了其再次堆垛,实现了石墨烯与NiFe2O4的良好复合。初步讨论了Gr/NiFe2O4纳米复合材料的形成机制,Ni2+、Fe3+在GO的含氧基团处非均相成核,在水热条件下不断长大,其生长过程遵循Ostwald熟化理论,即小尺寸的NiFe2O4粒子由于其较高的表面能而逐渐溶解,被那些尺寸较大的粒子消耗。     

石墨烯-硒化银纳米复合材料的制备、表征及光学性能研究

运用简单的一步反应水热法制备了石墨烯-硒化银(G-Ag2Se)纳米复合材料。用X射线粉末衍射(XRD)、傅里叶变换红外光谱(FTIR)和透射电子显微镜(TEM)等手段对所得产物进行了系统的表征。结果表明,反应体系中,硒化银纳米粒子的形成与氧化石墨烯的还原同时进行。石墨烯氧化物被充分地还原为石墨烯,并且Ag2Se纳米粒子均匀地分布在石墨烯的片层上,形成纳米复合材料。对所制备的G-Ag2Se纳米复合材料的光学性质也进行了研究。     

Facile sonochemical synthesis and photocatalysis of Ag nanoparticle/ZnWO_4-nanorod nanocomposites

A facile sonochemical method was developed to synthesize metallic Ag spherical nanoparticles on the surface of ZnWO_4 nanorods by forming heterostructure Ag/ZnWO_4 nanocomposites.The Ag/ZnWO_4 nanocomposites were characterized by X-ray powder diffraction(XRD),Fourier transform infrared spectroscopy(FTIR),field emission scanning electron microscopy(FESEM),transmission electron microscopy(TEM)and X-ray photoelectron spectroscopy(XPS).The experimental results showed that fcc metallic Ag nanoparticles were supported on surface of monoclinic sanmartinite ZnWO_4 nanorods.The Ag3d_(3/2) and Ag 3 d_(5/2) peaks have well-separated binding energies of 6.00 eV,certifying the existence of metallic Ag.The Ag/ZnWO_4 nanocomposites were evaluated for photodegradation of methylene blue(MB)induced by ultraviolet-visible(UV-Vis)radiation.In this research,heterostructure 10 wt% Ag nanoparticle/ZnWO_4-nanorod composites have the highest photocatalytic activity of 99%degradation of MB within 60 min.The increase in photocatalytic activity was the result of photoinduced electrons in conduction band of ZnWO_4 that effectively diffused to metallic Ag spherical nanoparticles and the inhibition of electron-hole recombination process.     

Corrosion behavior of GO-reinforced TC4 nanocomposites manufactured by selective laser melting

To improve the corrosion resistance of Ti–6Al–4V (TC4) matrix, the influence on the corrosion behavior, microhardness, and microstructure of graphene oxide (GO)-reinforced TC4 nanocomposites manufactured by selective laser melting was systematically investigated in this study. Microhardness tester, profilometer, X-ray diffractometer, scanning electron microscopy, and electrochemical workstation were used to characterize the association between microhardness, pore microstructures, hard phases, and corrosion resistance of GO/TC4 nanocomposites. It can be observed that the incorporation of GO promotes the in situ formation of hard phases, such as TiC, TiO₂, Al₂O₃, and so forth, and it also changes the microstructure of the matrix as well as increases its porosity. Nevertheless, GO/TC4 nanocomposites perform the best corrosion resistance when the mixing content of GO is 0.5 wt%, and its microhardness is greatly improved with the addition of GO. All experimental results suggest the efficacy of added GO.     

Ag2S/rGO纳米复合材料的细菌还原制备及光电性能研究

以一种革兰氏阴性菌(S. oneidensis MR-1)为生物还原剂,Na2S2O3为电子受体,在氧化石墨烯(GO)表面原位合成了Ag2S/rGO纳米复合材料,对其进行了表征和光电性能测试。结果表明,细菌还原得到粒径约10 nm的Ag2S纳米粒子,均匀分布在还原氧化石墨烯(rGO)上;光电性能测试表明,与纯Ag2S相比,Ag2S/rGO纳米复合材料电极的光电流密度约提高了3倍,光生电子-空穴对的分离效率更高,表现出更加优异的光电化学性能。     

Influence of Ag doped graphene on electrochemical behaviors and specific capacitance of polypyrrole-based nanocomposites

In this work, silver (Ag) nanoparticles were deposited on graphene sheets by chemical reduction and Ag-doped graphene (Ag-GR)/polypyrrole (PPy) nanocomposites were prepared by oxidation polymerization. The effect of the Ag-GR incorporation on the electrochemical properties of the PPy nanocomposites was investigated. It was found that highly dispersed Ag nanoparticles (2–5 nm) could be deposited onto the GR and that Ag-GR was successfully coated by PPy. From the cyclic voltammograms, Ag-GR showed higher electrocatalytic activity than that of pristine GR. Furthermore, the Ag-GR/PPy showed remarkably increased current density, quicker response, and better specific capacitance compared with GR/PPy. This indicates that, due to their high electrocatalytic activity, the Ag nanoparticles deposited onto the GR serve as an efficiency catalyst to improve electrochemical performance of the GR/PPy and that they resulted in the increase of the charge transfer between GR and PPy by bridge effect.     

石墨烯负载纳米LaF_3复合材料的摩擦学性能

采用液相超声直接剥离法制备了石墨烯负载纳米LaF_3复合材料,用SEM、TEM对其形貌进行了表征,利用多功能往复摩擦磨损试验仪考察了石墨烯负载纳米LaF_3复合材料在纯水中的摩擦磨损性能。通过SEM、XPS分别分析了磨痕表面的形貌、典型元素的化学状态,初步探讨了石墨烯负载纳米LaF_3复合材料在纯水中的润滑机理。结果表明:纳米LaF_3均匀分布于多层石墨烯片层表面和层间,其粒径为5~50 nm;其作为纯水添加剂具有良好的减摩抗磨性能,如试验载荷10 N,添加剂浓度0.01%(质量分数)时,与纯水润滑时相比,石墨烯负载纳米LaF_3复合材料水分散体系润滑下平均摩擦系数和磨损体积分别下降34.35%和52.40%,这主要是由于复合材料在磨损表面形成的吸附膜、摩擦化学反应膜发生协同作用,改变了水的磨损机理,抑制了Fe的氧化,使得摩擦表面的摩擦磨损得到减轻。     

氧化石墨烯化学接枝提高纳米银的负载效果

目的 分别使用酰氯法和氨基开环法接枝修饰氧化石墨烯(GO),利用接枝分子的"锚定效应"提高纳米银颗粒在GO表面的分散效果.方法 先对GO-Cl-DA(GO经酰氯化后接枝对苯二胺)和GO-DA(采用"一锅法"对GO和对苯二胺直接混合接枝)进行比较,之后又比较了先接枝后沉积纳米粒子(两步法)和接枝/沉积同时进行(一步法)得到的杂化材料.采用红外光谱、X射线衍射谱、X射线光电子能谱和热失重曲线等,分析了材料的组成、热稳定性、接枝方式、银纳米颗粒的负载效果等.结果 在氨基与环氧基开环反应或酰胺键的作用下,对苯二胺分子能有效地接枝在GO表面,其中,"一锅法"(即氨基开环法)的接枝效率较高,操作简便.在沉积银的过程中,两步法对基底还原程度更彻底,纳米银的负载量从一步法的1.01％(原子数分数)提高到了7.22％,且分散性更好,并由此提出了接枝小分子对纳米颗粒的锚定效应.结论 含有氨基的分子对氧化石墨烯进行修饰时,采用氨基开环法既简单,又高效,接枝分子通过锚定效应改善原位沉积的无机纳米粒子,可获得负载效果优异的杂化材料.     

Ag/TiO2纳米管的制备及其光催化性能

对纯钛片进行阳极氧化,得到长度约2 μm的TiO_2纳米管,在AgNO_3溶液中TiO_2纳米管在紫外光照射下,成功的将Ag~+离子还原为Ag单质,并沉积在TiO_2纳米管表面;用XRD,SEM和XPS对制备的样品进行表征,结果显示:Ag微粒(10～120 nm)是以单质的形式,不均匀的分布在TiO_2纳米管表面,并具有很好的化学稳定性;Ag/TiO_2纳米管光电催化效率随Ag量的增加而增加,但超过最佳值后降解效率就会下降:实验显示Ag含量为1.15%的Ag/TiO_2纳米管降解效率最高,紫外光照射3 h后,初始浓度为10×10~(-6)mol/L的亚甲基蓝溶液降解率达到100%,比未掺杂Ag的TiO_2纳米管降解效率提高了22.98%.     

多孔钛表面聚多巴胺层修饰及其载银研究

通过多巴胺自聚合在碱热处理多孔钛表面构建了聚多巴胺(PDA)膜层,利用聚多巴胺自身的还原性,成功将纳米银颗粒载入聚多巴胺修饰多孔钛表面,并探讨了沉积时间对纳米银颗粒负载量的影响。利用傅里叶变换红外光谱仪(FTIR)、场发射扫描电镜(FE-SEM)、能谱仪(EDS)、接触角测定仪和X射线光电子能谱(XPS)对聚多巴胺修饰及其载银多孔钛表面进行表征。研究结果表明,多巴胺能够在多孔钛表面自聚合形成聚多巴胺层,保留了钛表面的多孔结构;纳米银颗粒均匀沉积在PDA修饰的多孔钛表面,随着沉积时间的增加,多孔钛表面纳米银颗粒的负载量增加。     

氧化石墨烯对锂基润滑脂摩擦学性能的影响

目的 研究氧化石墨烯(GO)作为添加剂对润滑脂摩擦性能的影响.方法 将鳞片石墨利用经典的Hummers氧化法氧化得到GO,并表征了GO,再分别以不同的质量分数(0.1％、0.3％、0.5％、1.0％、1.5％)与润滑脂复配.同时增加了空白润滑脂与石墨粉复配的润滑脂作为对比.利用Optimol SRV型摩擦磨损试验机评价其摩擦学性能.利用非接触三维表面轮廓仪、扫描电子显微镜(SEM)观察磨斑表面和深度.通过特征X射线能谱仪(EDS)和X射线光电子能谱仪(XPS),对磨斑表面的元素化学状态分布进行分析.结果 与空白锂基润滑脂相比,添加了石墨粉的锂基润滑脂在经过钢/钢摩擦副的摩擦后,其摩擦因数均有降低,但随着试验的进行,其摩擦因数均逐渐提高,摩擦副表面出现了润滑失效的现象,而添加GO的锂基润滑脂其摩擦因数迅速降低至0.13左右,降低了35％,且在试验时间内没有出现润滑失效的现象.SEM及三维轮廓图显示,在添加GO的润滑脂润滑后,其钢块磨斑最低,磨痕最浅;EDS显示其润滑后的磨痕有较多的氧元素,说明具有含氧官能团的GO能够牢固地吸附在基体表面,形成润滑层.XPS证实了分别添加有石墨和GO的润滑脂在摩擦试验过程中均与基体发生了摩擦化学反应,由铁的氧化物形成了一层润滑薄膜.结论 GO作为润滑脂添加剂可以有效降低摩擦因数,减少磨损量,延长润滑时间,提高润滑性能.     

氧化铜纳米棒/氧化石墨烯的制备及催化性能测试

氧化铜纳米棒/氧化石墨烯（CuO-NRs/GO）新型复合材料通过在氧化铜纳米棒上静电吸附氧化石墨烯而制备出来。通过XRD、TEM、SEM以及FT-IR对其结构和形貌进行了表征,并研究了其在超声条件下对罗丹明B的催化降解性能。结果表明：CuO-NRs/GO对罗丹明B有很好的催化降解性能。     

Ag/AgCl-decorated polypyrrole nanotubes and their sensory properties

A facile method to prepare Ag/AgCl-decorated polypyrrole nanotubes (PPy/Ag–AgCl nanocomposites) has been demonstrated. PPy nanotubes were assembled on the reactive self-degraded template of a fibrillar complex of FeCl₃ and methyl orange (MO). By introducing PPy nanotubes into AgNO₃ solution, Ag and AgCl nanoparticles could be uniformly decorated onto the PPy nanotube surface in situ by the reaction of PPy and AgNO₃. The morphology and structure of the nanocomposites were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The possible application of PPy/Ag–AgCl nanocomposites as a vapor sensor has also been reported. The responses of these nanocomposites were observed to be reversible by monitoring the change in the resistance of the nanocomposites upon exposure to ammonia vapor. PPy/Ag–AgCl composite nanotubes sensors showed enhanced chemiresistor sensitivity compared with PPy nanotubes.     

Au/CdTe纳米复合材料的静电作用制备及表征(英文)

将相反电荷的纳米Au和纳米CdTe通过静电作用得到纳米复合Au/CdTe粒子。在水溶液中分别用二甲氨基吡啶和巯基丙酸稳定纳米Au和CdTe粒子,使其表面分别带有正电荷与负电荷。Au/CdTe纳米复合材料的表面等离子体吸收光谱随着Au含量的增加而红移,表明纳米复合Au/CdTe粒子的长大是由于配位形成而引起的。纳米Au和纳米CdTe的比影响纳米复合Au/CdTe粒子的结构。复合纳米Au/CdTe粒子的尺寸和形状是影响金属/半导体纳米复合材料性能的重要参数。用小角X射线散射技术、透射电子显微镜、循环伏安法和X射线光电子能谱来表征纳米复合Au/CdTe粒子。     

微波原位制备作为锂离子电池电极材料的石墨烯/TiO2 纳米复合物

通过改造的家用微波炉,实现了原位高效制备石墨烯/TiO₂纳米复合物。结果表明：微波辅助法能够在商用锐钛矿型TiO₂纳米颗粒表面均匀制备石墨烯纳米片,通过SiO₂/Si的剧烈电晕放电,其制备时间仅需数分钟（最短3 min）。石墨烯纳米片的尺寸大约为50 nm且缺陷很少。TiO₂晶体结构仍为锐钛矿型,主要归功于极短的制备周期和较低的反应温度（600~700 ℃）。石墨烯具有优异的电导率,可以提升锂离子扩散速率、提高电子传输速率并降低接触电阻。在1 C（170 mA·g^-1）条件下石墨烯/TiO₂纳米复合物的电池放电比容量提高了2倍。与商业化锐钛矿型TiO₂纳米颗粒相比,在1 C到5 C的不同充放电倍率下,石墨烯/TiO₂纳米复合物的比容量差距显著扩大。     

钴纳米粒子改性石墨烯复合材料的电磁性能

采用化学镀的方法,先后用氯化亚锡敏化、氯化钯活化,在石墨烯表面沉积钴纳米粒子。XRD、TEM结果显示钴在石墨烯表面的晶体结构和含量因钴前驱体盐和还原剂浓度而异。电磁测试结果表明:钴含量的增加和石墨烯的还原均能提升Co-RGO的电导率;同时,Co-RGO纳米复合材料由于具有磁损耗和大量界面引入的介电损耗,吸波性能优异,Co-RGO*1在1~18 GHz频段内反射率低于-10 d B的频宽约为4 GHz,Co-RGO*2在26.5~40 GHz频段内反射率均小于-23 d B。     

Effect of Ag nanoparticles on the electron energy structure and electrical properties of poly(p-phenylene vinylene) (PPV)

The effects of inorganic nanoparticles on a conjugated polymer were investigated by measuring the electronic properties of poly(p-phenylene vinylene) (PPV) and PPV/Ag nanocomposites. Through hybridization, an enhancement in current density was achieved with PPV/Ag nanocomposites due to an increase in the electron affinity with Ag nanoparticle content. Furthermore, roughening of the surface morphology was observed with incorporation of Ag nanoparticles. This roughness induces an enhanced applied field at the thinner region of the film and an increase in the surface area with a resulting increase of electron injection, leading to current enhancement.     

LaNiO3/石墨烯复合薄膜的制备及光催化性能

采用改进的Hummer法制备出薄层石墨烯材料,采用溶胶-凝胶法结合旋转涂膜技术以玻璃基底制备出石墨烯基LaNiO3复合薄膜。采用X射线衍射(XRD)仪,透射电镜(TEM),扫描电镜(SEM),拉曼光谱,X射线衍射光电子能谱(XPS)、紫外-可见(UV-Vis)吸收光谱和荧光光谱(PL)等测试手段对复合薄膜进行表征。结果表明,晶粒粒径约为20 nm的LaNiO3较均匀地生长在了石墨烯片上。光催化性能研究表明,LaNiO3/石墨烯复合薄膜的光催化活性显著优于LaNiO3薄膜,当石墨烯的含量约为4%时,复合薄膜4 h内对酸性红的降解效率比LaNiO3薄膜提高了1倍。     

一种无铼二代镍基单晶高温合金蠕变机制研究

利用层层静电自组装技术将聚乙烯亚胺(PEI-Ag+)、PdCl42-交替沉积在基底上,然后用硼氢化钠还原,构筑了含银/钯复合纳米粒子的PEI-Ag/Pd纳米复合薄膜.通过扫描电子显微镜(FESEM),X射线光电子能谱(XPS)和循环伏安(CV)等手段对复合膜的成分、微结构和性质进行了测试分析.膜上生成了不规则和立方体状的银/钯纳米复合物,导致膜表面有一定的粗糙度.结果表明,双金属{PEI-Ag/Pd}n复合膜比单金属{PEI/Pd}n或{PEI-Ag/PSS}n膜对多巴胺的氧化有更好的电催化活性.