共查询到18条相似文献,搜索用时 93 毫秒
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本文采用改进的Hummers法对天然鳞片石墨进行氧化处理制备氧化石墨,并采用机械研磨还原法,制备了还原的氧化石墨样品,研究了机械研磨时间对还原性氧化石墨导电性的影响。采用XRD、红外光谱和紫外光谱对样品进行了结构,谱学和化学成分表征,发现机械研磨能使氧化石墨的含氧官能团减少;在一定时间内研磨能还原氧化石墨,研磨时间过长又会重新氧化;机械研磨20h,还原性氧化石墨样品的导电性最高,为26S/cm,继续研磨,还原性氧化石墨样品的导电性又会下降。结果表明,机械研磨法能够还原氧化石墨,且与研磨时间有关,为还原氧化石墨的研究提供了新的参考。 相似文献
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氧化还原法制备石墨烯因原材料价格低廉、制备工艺简单,被认为是一种适应大规模制备石墨烯的途径,其中氧化石墨的还原是制备电学性能、力学性能与热稳定性优异的石墨烯的关键,而不同的还原方法对石墨烯的结构和性能影响较大。综述了氧化还原法制备石墨烯的还原方法,以及将石墨烯引入到陶瓷材料中所存在的问题和相应的解决方法。探讨了石墨烯对耐火材料在改善材料的强度和热震性的应用前景,并且指出了今后石墨烯在耐火材料中的应用需要重视的几个关键性问题。 相似文献
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基于高能微波处理技术,在强烈的非稳态条件下对氧化石墨进行剥离/还原,实现了石墨烯的快速制备。结果表明,经功率为6kW微波辐照,在≤35kPa的低真空谐振腔中,只用10s左右即可实现氧化石墨片层快速彻底的剥离,并可实现原位还原。通过SEM,TEM,TG-DSC等的微观结构表征显示,多数产物层数在2~3层之间,且样品中残留的含氧基团非常少。但也由于强烈的非稳态过程,石墨烯的制备效果存在着一定的分散性,样品中也夹杂有极少量层数约为10~20层的石墨烯微片。结果表明,采用高能微波辐照,并结合施加的真空环境,有助于强化或促进碳环片层的剥离/还原效果,实现高质量石墨烯的高效快速获取。 相似文献
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化学还原石墨烯薄膜的制备及结构表征 总被引:1,自引:1,他引:0
以天然鳞片石墨为原材料,采用Hummers法成功制备了氧化石墨,并采用化学还原方法制备石墨烯薄膜材料,分别应用X射线衍射(XRD)、能谱分析(EDS)、拉曼光谱分析(Raman)、傅里叶变换红外光谱(FTIR)和扫描电镜(SEM)对氧化石墨和化学还原石墨烯薄膜的性能、结构和形貌进行了表征。实验结果表明,通过控制溶液的pH值为10可防止石墨烯团聚,石墨烯溶液的分散性非常好,碳氧比达到了8.8∶1,扫描电镜图片观察到了较薄的片层。通过XRD图谱可以看出,石墨烯薄膜比原始石墨的层间距变大。拉曼光谱表明,石墨烯薄膜相对氧化石墨的ID/IG值更大,样品在还原的过程中无序度增加。石墨烯薄膜的微观结构研究为其在超级电容器电极或重金属废水过滤膜等方面的应用提供了理论基础。 相似文献
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用Hummers法制备了氧化石墨烯,将其在氯化镍溶液中分散均匀,采用水合肼还原氧化石墨烯和镍离子,制备出石墨烯负载纳米镍磁性复合材料。采用FTIR、XRD、SEM、Raman和VSM观察分析了氧化、还原过程中样品的结构演变及静态磁性能,结果表明,氧化石墨烯表面含有大量氧化基团,其晶间距较鳞片石墨大,并呈现出非晶特征。还原后纳米镍颗粒分布在石墨烯表面和层间,当镍添加量从10%(w)增加至50%时,复合材料的饱和磁化强度从0升高至50 emu/g,矫顽力从25 Oe升高至205 Oe。 相似文献
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通过优化Hummers法制备了氧化石墨烯,并用水合肼还原法制备了石墨烯,且对自制的石墨烯和氧化石墨烯进行了测试及分析;然后通过溶液插层法制得纳米级聚乳酸/石墨烯和聚乳酸/氧化石墨烯复合材料,并对其分散性、热学性能以及力学性能进行了分析。对石墨烯和氧化石墨烯的表征结果说明,水合肼可以还原氧化石墨,所制备的石墨烯纯度较高。对聚乳酸/石墨烯和聚乳酸/氧化石墨烯复合材料的性能分析结果表明,在聚乳酸的结晶度、结晶速率和对聚乳酸的结晶成核上,石墨烯比氧化石墨烯具有更优异的表现,但在热稳定性能方面,氧化石墨烯比石墨烯优异;在力学性能方面,有增强和降低两种影响,添加少量氧化石墨烯时聚乳酸的力学性能降低,而含质量分数为0.5%的石墨烯复合材料在拉伸实验和冲击实验中的增强效果较为明显。 相似文献
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Qin X Lu W Luo Y Chang G Asiri AM Al-Youbi AO Sun X 《Journal of nanoscience and nanotechnology》2012,12(4):2983-2989
In this paper, a stable aqueous dispersion of graphene nanosheets (GNs) has been prepared by chemical reduction of graphene oxide (GO) with hydrazine hydrate in the presence of poly [(2-ethyldimethylammonioethyl methacrylate ethyl sulfate)-co-(1-vinylpyrrolidone)] (PQ11). Taking advantages of the fact that PQ11 is a positively charged polymer exhibiting reducing ability, we further demonstrated the subsequent decoration of GN with gold nanoparticals (AuNPs) by in-situ chemical reduction of HAuCl4. It was found that such nanocomposites exhibit good catalytic activity toward 4-nitrophenol (4-NP) reduction and the GN supports also enhance the catalytic activity via a synergistic effect. 相似文献
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M SELVAM K SAKTHIPANDI R SURIYAPRABHA K SAMINATHAN V RAJENDRAN 《Bulletin of Materials Science》2013,36(7):1315-1321
Graphene has superior electrical conductivity than graphite and other allotropes of carbon because of its high surface area and chemical tolerance. Electrochemically processed graphene sheets were obtained through the reduction of graphene oxide from hydrazine hydrate. The prepared samples were heated to different temperatures such as 673 and 873 K. X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDXS), transmission electron microscopy (TEM), Raman spectra and conductivity measurements were made for as-prepared and heat-treated graphene samples. XRD pattern of graphene shows a sharp and intensive peak centred at a diffraction angle (2θ) of 26·350. FTIR spectra of as-prepared and heated graphene were used to confirm the oxidation of graphite. TEM results indicated that the defect density and number of layers of graphene sheets were varied with heating temperature. The hexagonal sheet morphology and purity of as-prepared and heat treated samples were confirmed by SEM–EDX and Raman spectroscopy. The conductivity measurements revealed that the conductivity of graphene was decreased with an increase in heating temperature. The present study explains that graphene with enhanced functional properties can be achieved from the as-prepared sample. 相似文献
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采用水合肼还原氧化石墨烯(GO)制备了还原氧化石墨烯(RGO),以RGO作为分散介质加入到天然橡胶(NR)和丁腈橡胶(NBR)基体中,通过乳液共混法制备了RGO/NR-NBR复合材料。采用FTIR、Raman、XRD及SEM等手段表征了RGO的结构和形貌,测试结果表明,水合肼还原GO效果较好,基本除去含氧官能团,同时RGO还保留了GO的片层结构。RGO/NR-NBR复合材料的SEM测试结果显示,纳米尺寸的RGO均匀分散在橡胶基体中,且复合材料的拉伸断面粗糙程度显著增加。RGO/NR-NBR复合材料的硫化性能测试结果表明,随RGO的含量增加,复合材料的交联密度、最大扭矩及扭矩差均增大。RGO/NR-NBR复合材料的力学性能随RGO含量的增加而提高,当RGO含量为3.0%时,材料的拉伸强度、100%定伸强度和邵氏硬度分别提高了65.7%、90.3%和21.1%,断裂伸长率降低了13.1%。 相似文献
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Graphene oxide (GO) was successfully prepared by a modified Hummer's method. The reduction effect and mechanism of the as-prepared GO reduced with hydrazine hydrate at different temperatures and time were characterized by x-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), elemental analysis (EA), x-ray diffractions (XRD), Raman spectroscopy and thermo-gravimetric analysis (TGA). The results showed that the reduction effect of GO mainly depended on treatment temperature instead of treatment time. Desirable reduction of GO can only be obtained at high treatment temperature. Reduced at 95?°C for 3 h, the C/O atomic ratio of GO increased from 3.1 to 15.1, which was impossible to obtain at low temperatures, such as 80, 60 or 15?°C, even for longer reduction time. XPS, 13C NMR and FTIR results show that most of the epoxide groups bonded to graphite during the oxidation were removed from GO and form the sp(2) structure after being reduced by hydrazine hydrate at high temperature (>60?°C), leading to the electric conductivity of GO increasing from 1.5 × 10(-6) to 5 S cm(-1), while the hydroxyls on the surface of GO were not removed by hydrazine hydrate even at high temperature. Additionally, the FTIR, XRD and Raman spectrum indicate that the GO reduced by hydrazine hydrate can not be entirely restored to the pristine graphite structures. XPS and FTIR data also suggest that carbonyl and carboxyl groups can be reduced by hydrazine hydrate and possibly form hydrazone, but not a C = C structure. 相似文献