纳米碳化钨的制备及电化学催化性能研究

以新制备的过氧钨酸和酚醛树脂为原料合成碳化钨(WC)前驱体,分别以H2和Ar为还原及保护气体,原位碳化制备纳米WC粉体.使用FTIR、XRD及SEM对试样的理化特性进行表征,并采用循环伏安法测试Pt/WC复合材料的电化学催化活性及其稳定性.结果表明,实现了低温原位碳化制备纯度高的纳米WC粉体,粉体颗粒粒径为15～100nm,颗粒形貌近似球形.WC可与Pt协同作用加强H2的电催化氧化作用,10%Pt/WC(质量分数)展现了较好的催化稳定性和活性,其电流密度可达49.58mA/cm2.     

碳化细菌纤维素/石墨烯(CBC/CCG)复合材料的制备及电化学性能研究

将氧化石墨烯(GO)与碳化细菌纤维素(CBC)(7∶3,质量比)超声复合,用水合肼原位还原制得碳化细菌纤维素/石墨烯(CBC/CCG)复合材料。利用动态力显微镜(DFM)、扫描显微镜(SEM)、X射线衍射(XRD)、激光拉曼光谱(Raman)对其形貌、结构进行表征。并通过循环伏安、交流阻抗、恒流充放电测试等方法比较了CBC/CCG复合材料和石墨烯(CCG)作为超级电容器电极在6mol/L KOH溶液中的电容性能。结果表明,在10mA/cm2电流密度下,CCG比容量为87.79F/g,CBC/CCG复合材料的比容量达到168.99F/g,CBC/CCG复合材料的电化学性能要优于CCG,具有良好应用前景。     

武术训练对多巴胺在纳米金修饰微玻碳电极上的电化学行为变化研究

目的：建立运动活性物质多巴胺（DA）在纳米金修饰微玻碳电极（NG／GCE）上的检测技术在武术训练中的应有。方法：应用循环伏安法（CV）研究人体运动应急激素DA在纳米金修饰微玻碳电极上的电催化反应及定量测定。     

异鼠李素的电化学行为及其测定

采用循环伏安法研究异鼠李素在电极上的电化学行为,建立差示脉冲伏安法测定其含量的电化学分析新方法。在pH 4.0醋酸盐缓冲液中,氧化峰电流与异鼠李素浓度在2.0×10~(-7)～1.2×10~(-6)mol·L~(-1)范围内呈良好的线性关系,检测限为3.0×10~(-8)mol·L~(-1)。玻碳电极可有效消除样品中其它组分对异鼠李素测定的干扰,已成功用于实际样品中异鼠李素含量的直接测定。该方法灵敏度高、检测范围宽,结果令人满意。     

表面沉积铜纳米颗粒的细菌纤维素/壳聚糖交联复合膜的制备及其抗菌性能研究

通过戊二醛交联制备了细菌纤维素/壳聚糖复合材料,并采用磁控溅射技术在交联复合膜表面沉积铜(Cu)纳米颗粒。利用扫描电子显微镜观察纳米纤维膜表面形貌,采用傅里叶红外光谱仪、热重分析仪和X射线衍射仪比较交联复合前后以及镀铜前后复合膜基本化学结构、热稳定性和晶面结构的变化。通过能量色散X射线光谱对壳聚糖和铜在复合膜表面的分布情况进行表征。同时借助抗菌实验探究复合膜对金黄色葡萄球菌和大肠杆菌的抗菌能力。结果表明:壳聚糖与细菌纤维素发生了有效交联,改变了细菌纤维素的基本形貌、化学结构、晶体形态以及热学性能,并且镀铜后交联复合膜的抗菌性能得到了明显的提升(膜与细菌接触20min,对金黄色葡萄球菌和大肠杆菌的抗菌效果均达到了99.999%)。     

细菌纤维素纳米棒阵列的制备

室温下,以细菌纤维素为基础材料,在其二甲基乙酰胺和溴化锂混合溶剂中,用溶剂挥发法,制得细菌纤维素纳米棒阵列。探讨了基底对形成细菌纤维素纳米棒阵列的影响。初步研究了细菌纤维素纳米棒阵列的形成机理。     

武术运动员体内多巴胺在模拟生理缓冲溶液中电化学实验研究

多巴胺（DA）存在于神经组织和体液中，是脑功能的物质基础，哺乳动物和人类中枢神经重要的信息传递物质。其代谢障碍会引起含量变化，从而导致某些疾病的发生。对于其测定方法的研究，将为其在武术运动中的应用具有重要的实际意义。     

纤维素制备碳材料的工艺与机理研究

以纤维素作原料,利用水热碳化法,在一定的温度和压强下制备碳纳米材料。通过单因素实验考察了反应温度、反应时间对产物表观形貌的影响。采用扫描电子显微镜(SEM)、X射线衍射仪(XRD)及红外光谱仪(FT-IR)对所得碳材料的微观形貌和表面生成的官能团进行表征与测试。结果表明:纤维素水热碳化的起始温度为230℃,290℃为最佳碳化温度;当T=290℃时,反应时间的延长可增大碳颗粒的球化趋势,而对粒径影响较小;经水热碳化制备的碳材料表面含有羟基、羰基和羧基等官能团。     

碳包铜纳米颗粒的制备及其性能研究

采用碳弧法制备出碳包铜纳米粒子,并用透射电子显微镜(TEM)、X射线衍射仪(XRD)和DSC对产物的形貌、尺寸、物相结构组成以及抗氧化性能进行了表征分析,同时对碳包铜纳米粒子的导电性能进行了测量.测试结果表明碳包铜纳米粒子为核壳型结构,内部为金属铜核,外部为碳层.在铜核的周围碳以类石墨状形式存在,离铜核较远处碳以非晶态...     

纳米碳颗粒负载碳化钼复合物的制备及其催化性能研究

利用爆炸辅助的化学气相沉积法成功地制备了纳米碳颗粒负载碳化钼的复合物,并利用TEM和XRD对合成纳米复合物的形貌和结构进行了表征;以环己烷脱氢反应为探针对其催化性能进行了评价,考察了钼含量对碳化钼复合物催化性能的影响.结果表明,纳米碳颗粒由有序度较低的石墨片层组成,形貌近似球形,粒度分布均匀,大小约为20nm,原位修饰的六方碳化钼分散在碳颗粒表面;钼含量不同,复合物对环己烷脱氢催化性能有较大差异,当钼含量为15%时,催化性能最好.     

Optical properties of chalcogenide glasses with ion-synthesized copper nanoparticles

Substrates of chalcogenide glassy semiconductors As₂S₃ and Ge_15.8As₂₁S_63.2 are implanted with Cu⁺ ions (energy 40 keV, radiation dose 1.5 × 10¹⁷ ion/cm², fixed current density in the ion beam 1 μA/cm²). The composite layers are analyzed by measuring linear optical transmittance and recording nonlinear optical absorption using the Z-scan technique at 780 nm (probe laser radiation with 150-fs pulses; intensity of 25–100 mW). It is ascertained for the irradiated materials that (1) the linear transmission characteristic of the optical surface plasmon resonance (SPR) band, which indicates the formation of copper nanoparticles in the near-surface region, has emerged and (2) there are simultaneously saturated and two-photon nonlinear absorption types; the latter prevails as the intensity of laser irradiation is increased.     

Influence of copper nanoparticles on copper requiring enzyme

This study describes the influence of copper nanoparticles (CNPs) on activity and kinetic properties of a Cu²⁺ requiring sorghum oxalate oxidase (OxO). CNPs were synthesised by citrate-induced reduction of CuCl₂ and their size (range 13–58?nm) was determined by transmission electron microscopy. The CNPs were characterised by scanning electron microscopy and X-ray diffraction studies. These CNPs enhanced OxO activity by 30%. Thermal and storage stability were increased, while Km value for oxalate decreased in the presence of CNPs. CNPs protected OxO against chelation by diethyldithiocarbamate, a Cu²⁺ specific chelator. The analytic use of OxO in the presence of CNP for determination of oxalate in food stuff is demonstrated.     

Bacterial synthesis of copper/copper oxide nanoparticles

A bacterial mediated synthesis of copper/copper oxide nanoparticle composite is reported. A Gram-negative bacterium belonging to the genus Serratia was isolated from the midgut of Stibara sp., an insect of the Cerambycidae family of beetles found in the Northwestern Ghats of India. This is a unique bacterium that is quite specific for the synthesis of copper oxide nanoparticles as several other strains isolated from the same insect and common Indian mosquitoes did not result in nanoparticle formation. By following the reaction systematically, we could delineate that the nanoparticle formation occurs intracellularly. However, the process results in the killing of bacterial cells. Subsequently the nanoparticles leak out as the cell wall disintegrates. The nanoparticles formed are thoroughly characterized by UV-Vis, TEM, XRD, XPS and FTIR studies.     

Synthesis of copper ferrite nanoparticles

Pseudospherical copper ferrite particles 20 to 90 nm in average size were prepared by an aerosol method through condensation of iron and copper vapors in an inert-gas flow, followed by the oxidation of the resulting two-phase powder under heterogeneous combustion conditions to an almost single-phase product. The nanoparticles were characterized by scanning electron microscopy, X-ray diffraction, BET measurements, and vibrating-sample magnetometry. Analysis of the X-ray diffraction data and the behavior of the magnetization of reaction intermediates and final synthesis products in the range 400–1100 K made it possible to propose models for the nanostructure of the particles and establish the likely sequence of the observed phase transformations.     

Synthesis and characterization of copper nanoparticles

Reduction of copper salt by sodium citrate/SFS and myristic acid/SFS leads to phase pure Cu nanoparticles. However, a similar reaction with hydrazine hydrate (HH) and sodium formaldehyde sulfoxylate (SFS) in polymer afforded only a mixture of Cu₂O and Cu. Copper nanoparticles so-prepared were characterized by UV-Visible spectroscopy, X-ray diffraction measurements (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Freshly prepared solutions showed an absorption band at about 600 nm due to surface plasmon resonance (SPR). XRD analysis revealed all relevant Bragg's reflection for fcc crystal structure of copper metal. The particle size by use of Scherrer's equation is calculated to be about 30 nm. TEM showed nearly uniform distribution of the particles in PVA.     

Nonaqueous phase synthesis of copper nanoparticles

Copper nanoparticles were synthesized in a nonaqueous solution of cetyltrimethylammonium bromide with isopropanol as a solvent. Cetyltrimethylammonium bromide in isopropanol is observed to play a role as a catalyst where isopropanol is the reducing agent. The surface plasmon band characteristic for Cu nanoparticles can be observed at approximately 560 nm in the UV-visible spectra at molar ratios for Cu2+: cetyltrimethylammonium bromide of 1:15 and 1:30. On the other hand, at molar ratios of 1:0.25 and 1:1 the presence of peak at approximately 310 nm can be attributed to oligomeric clusters of Cu0. Formation of Cu0 was further confirmed from the X-ray diffraction analysis. The diffractograms exhibited peaks at 2theta = approximately 41.6 degrees, approximately 51.6 degrees, and approximately 74.3 degrees, corresponding to Cu0. At lower concentration of cetyltrimethylammonium bromide (i.e., Cu2+: cetyltrimethylammonium bromide = 1:0.25) higher degree of size dispersity (particles between approximately 5-20 nm) can be noted from transmission electron micrograph. On the other hand, at the highest concentration of cetyltrimethylammonium bromide (i.e., Cu2+: cetyltrimethylammonium bromide = 1:30), formation of finer sized particles with a lower degree of size variation, approximately 2-10 nm, can be observed.     

Assessment of mechanical properties of concrete incorporating carbonated recycled concrete aggregates

An accelerated carbonation technique was employed to strengthen the quality of recycled concrete aggregates (RCAs) in this study. The properties of the carbonated RCAs and their influence on the mechanical properties of new concrete were then evaluated. Two types of RCAs, an old type of RCAs sourced from demolished old buildings and a new type of RCAs derived from a designed concrete mixture, were used. The chosen RCAs were firstly carbonated for 24 h in a carbonation chamber with a 100% CO₂ concentration at a pressure level of 0.1 Bar and 5.0 Bar, respectively. The experimental results showed that the properties of RCAs were improved after the carbonation treatment. This resulted in performance enhancement of the new concrete prepared with the carbonated RCAs, especially an obvious increase of the mechanical strengths for the concrete prepared with the 100% carbonated new RCAs. Moreover, the replacement percentage of natural aggregates by the carbonated RCAs can be increased to 60% with an insignificant reduction in the mechanical properties of the new concrete.     

Efficiency of surface modified Ti coated with copper nanoparticles to control marine bacterial adhesion under laboratory simulated conditions

Titanium (Ti) used as condenser material in nuclear power plants encounter severe biofouling in marine environment which in turn affects the efficiency of the metal. To reduce the biofouling by marine microorganisms, surface modification of the Ti was carried out by anodization process to obtain nanotubes (TiO₂-NTs). The electrolyte solution containing 1% of ammonium fluoride resulted in uniform growth of TiO₂-NTs. TiO₂-NTs were further coated with chemically synthesized copper nanoparticles (NT-CuNP) using 3-amino propyl triethoxy silane as a coupling agent. NT-CuNP was characterized by field-emission scanning electron microscopy (FE-SEM), energy-dispersive spectroscopy and X-ray diffraction. The stability of the coating was determined by the amount of Cu⁺ ions released into the surrounding using AAS. The microbial adhesion on the surface of Ti, TiO₂-NTs and NT-CuNP coupons were evaluated by sea water exposure studies using total viable count method and also characterized by FE-SEM for any morphological changes. The NT-CuNP coupons show a 60% reduction in microbial adhesion when compared to control Ti coupons.     

Low-macroscopic field emission properties of wide bandgap copper aluminium oxide nanoparticles for low-power panel applications

Field emission properties of CuAlO(2) nanoparticles are reported for the first time, with a low turn-on field of approximately 2 V μm(-1) and field enhancement factor around 230. The field emission process follows the standard Fowler-Nordheim tunnelling of cold electron emission. The emission mechanism is found to be a combination of low electron affinity, internal nanostructure and large field enhancement at the low-dimensional emitter tips of the nanoparticles. The field emission properties are comparable to the conventional carbon-based field emitters, and thus can become alternative candidate for field emission devices for low-power panel applications.