碳纤维表面金属覆银及其场发射特性研究

文章采用化学镀银对碳纤维（carbon fibers,CNFs）表面金属化,研究表面金属化碳纤维的场发射性能。实验结果表明,碳纤维表面金属化后体电阻率明显降低,场发射性能显著提高。当化学镀时间为15min,覆银碳纤维增重率AG／G约74％时,碳纤维体电阻率ρ降至4．09×10^-4Ω·cm,场发射性能最优;当电压为968V时出现亮点;电压为1,733V时,亮度最高达1,357cd／m^2。     

碳纤维表面金属化及其场发射特性研究

采用化学镀镍对碳纤维(Carbon fibers,CNFs)表面金属化,研究不同厚度的表面金属化碳纤维的场发射性能。实验结果表明,碳纤维表面金属化后体电阻率明显降低,场发射性能显著提高;厚度不同的金属化碳纤维的场发射性能不同。当化学镀时间为30 min,镍金属膜厚约3.25μm时,碳纤维体电阻率ρ降至1.35×10-4Ω.cm,场发射性能最优,当电压为638 V时出现亮点,电压为1 425 V时,亮度最高达988 cd/m2。     

Chemically Functionalized Natural Cellulose Materials for Effective Triboelectric Nanogenerator Development

Cellulose, the most abundant natural polymer, is renewable, biodegradable, and cost competitive. This paper reports the development of a high‐performance triboelectric nanogenerator (TENG) with both contacting materials made from cellulosic materials. Cellulose nanofibrils (CNFs) are used as the raw material, and chemical reaction approaches are employed to attach nitro groups and methyl groups to cellulose molecules to change the tribopolarities of CNF, which in turn significantly enhances the triboelectric output. Specifically, the nitro‐CNF possesses a negative surface charge density of 85.8 µC m^?2, while the methyl‐CNF possesses a positive surface charge density of 62.5 µC m^?2, reaching 71% and 52% of that for fluorinated ethylene propylene (FEP), respectively. The figure of merit of the nitro‐CNF and methyl‐CNF is quantified to be 0.504 and 0.267, respectively, comparable to or exceeding a number of common synthetic polymers, such as Kapton, polyvinylidene fluoride, and polyethylene. The TENG fabricated from nitro‐CNF paired with methyl‐CNF demonstrates an average voltage output of 8 V and current output of 9 µA, which approaches the same level obtained from TENG made from FEP. This work demonstrates a successful strategy of using environmentally friendly, abundant cellulosic materials for replacing the synthetic polymers in TENG development.     

The NADH Electrochemical Detection Performed at Carbon Nanofibers Modified Glassy Carbon Electrode

In this work, the capability of carbon nanofibers to be used for the design of catalytic electrochemical biosensors is demonstrated. The direct electrochemistry of NADH was studied at a glassy carbon electrode modified using carbon nanofibers. A decrease of the oxidation potential of NADH by more than 300 mV is observed in the case of the assembled carbon nanofiber‐glassy carbon electrode comparing with a bare glassy carbon electrode. The carbon nanofiber‐modified electrode exhibited a wide linear response range of 3×10^?5 to 2.1×10^?3 mol L^?1 with a correlation coefficient of 0.997 for the detection of NADH, a high specific sensitivity of 3637.65 (μA/M cm²), a low detection of limit (LOD=3σ) of 11 μM, and a fast response time (3 s). These results have confirmed the fact that the carbon nanofibers represent a promising material to assemble electrochemical sensors and biosensors.     

Application of carbon-based nanomaterials in sample preparation: A review

In this paper, a broad overview on the applications of different carbon-based nanomaterials, including nanodiamonds, fullerenes, carbon nanotubes, graphene, carbon nanofibers, carbon nanocones-disks and nanohorns, as well as their functionalized forms, in sample preparation is provided. Particular attention has been paid to graphene because many papers regarding its application in this research field are becoming available. The distinctive properties, derivatization methods and application techniques of these materials were summarized and compared. According to their research status and perspective, these nanomaterials were classified in four groups (I: graphene and carbon nanotubes; II: carbon nanofibers; III: fullerenes; and IV: nanodiamonds, carbon nanocones/disks and carbon nanohorns) and characteristics and future trends of every group were discussed.     

一维碳纤维承载AgX/TiO2(X=Br,I)三元复合材料的制备及光催化性能

利用静电纺丝技术结合高温煅烧过程制备碳纤维(CNFs)载体材料, 进一步通过溶剂热和化学反应过程获得AgX/TiO₂ /CNFs(X=Br, I)复合光催化剂. 利用X射线衍射(XRD)、 扫描电子显微镜(SEM)、 红外光谱(FTIR)等测试手段表征了材料的结构及形貌. 通过在可见光下降解甲基橙考察了催化材料的光催化性能. 结果表明, 该复合材料具有高吸附性、 良好的传导性以及较好的光敏性, 从而使其具有较好的可见光催化活性; 同时以一维碳纤维作为载体, 使其更容易分离、 回收, 更具有实际应用价值.     

Modelling the effects of nitrogen doping on the carbon nanofiber growth via catalytic plasma‐enhanced chemical vapour deposition process

An analytical model is developed to describe the effects of nitrogen doping on the growth of the carbon nanofibers (CNFs) and to elucidate the growth mechanism of nitrogen‐contained carbon nanofibers (N‐CNFs) on the catalyst substrate surface through the plasma‐enhanced chemical vapour deposition (PECVD) process. The analytical model accounts for the charging of CNFs, kinetics of all plasma species (electrons, ions, and neutrals) in the reactive plasma, generation of carbon species on the catalyst nanoparticle surface due to dissociation of hydrocarbons, CNF growth due to diffusion and precipitation of carbon species, and various other processes. First‐order differential equations have been solved for glow discharge plasma parameters for undoped CNFs (CNF growth in C₂H₂/H₂ plasma) and nitrogen‐doped CNFs (N‐CNF growth in C₂H₂/NH₃ plasma). Our investigation found that nitrogen‐doped CNFs exhibit lower tip diameters and smaller heights compared to the undoped CNFs. In addition, we have estimated that nitrogen‐doped CNFs have more enhanced field emission characteristics than the undoped CNFs. Moreover, we have also observed that N‐CNFs' growth rate increases and tip diameter decreases as the C₂H₂/NH₃ gas ratio decreases. The theoretical results of the present investigation are consistent with the existing experimental observations.     

碳纤维表面化学镀覆Ni纳米薄膜制备及其FED器件场发射特性

文章利用化学镀在碳纤维CNFs表面制备了镍金属纳米薄膜,并对其FED器件场发射特性进行测试。结果证明,碳纤维化学镀镍之后,其场发射特性显著提高。当化学镀时间为30分钟,pH值为4.6时,碳纤维化学镀镍的增重率ΔG/G为49.5%,扫描电子显微镜（SEM）和能谱分析（EDS）研究表明,碳纤维CNFs表面覆镀的Ni金属薄膜表面平整、致密。当电压为832V时,出现亮点,当电压为1,456V时,场发射电流强度I为0.65mA。数值计算可得,镀镍碳纤维CNFs的场增强因子β为1,376,是碳纤维场增强因子的4.83倍。     

基于纳米银/碳纳米纤维复合材料的增强效应电化学测定多贝斯

将银纳米粒子(AgNPs)电沉积在碳纳米纤维(CNFs)修饰玻碳电极表面制备纳米银/碳纳米纤维修饰玻碳电极(AgNPs/CNFs/GCE).采用扫描电镜考察其表面形态,在K3[Fe(CN)6]-K4[Fe(CN)6]体系中用循环伏安法和电化学阻抗法研究AgNPs/CNFs/GCE的电化学行为.采用循环伏安法和方波伏安法...     

The reinforcement ability of ozone-treated CNFs on mechanical properties of C–epoxy composites

Carbon nanofibers (CNFs) are ozone-treated for different time durations (45 and 90 min). Changes in surface characteristics of CNFs due to ozone treatment were studied with BET surface area analyzer and Raman spectroscopy. Raman spectroscopic studies showed that ozone treatment is imparting enhanced degree of disorder for CNFs. Changes in surface functional groups of CNFs due to ozone treatment were estimated using elemental analysis and thermogravimetric analysis. The influence of ozone-treated CNFs on the mechanical properties of laminated (2D) carbon fiber-reinforced epoxy matrix (CFRP) composites has been studied. Results indicate that ozone-treated CNFs can improve the mechanical properties of CFRPs significantly as compared to untreated CNFs due to enhanced interface compatibility between the ozone-treated CNFs to the matrix. Ozone treatment of CNFs proposed in this study has the potential to overcome the limitations of the conventional methods of generating functional groups.