共查询到19条相似文献,搜索用时 104 毫秒
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利用改进的Hummer法制备氧化石墨,然后分别采用化学还原法和热还原法将氧化石墨还原制得功能化石墨烯。采用X-射线衍射(XRD)、扫描电镜(SEM)、傅立叶红外(FT-IR)和热重(TG)等表征手段对功能化石墨烯制备过程中的原料石墨、氧化石墨和石墨烯进行了表征。结果表明,化学还原法和热还原法都能还原氧化石墨制得功能化石墨烯,但还原程度不同。与化学还原法相比,热还原法制备的功能化石墨烯含有较少含氧基团,且工艺简单,耗时少,是一种高效制备大量功能化石墨烯的方法。 相似文献
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还原氧化石墨烯横向尺寸分布影响因素初探 总被引:3,自引:0,他引:3
化学还原剥离氧化石墨法制备的还原氧化石墨烯具有诸多优异性能,但所得还原氧化石墨烯横向尺度差异较大.利用化学还原法制备了还原氧化石墨烯,基于还原氧化石墨烯的AFM观测结果,初步统计分析了静置、磁力搅拌、离心和超声处理及它们的次序对还原氧化石墨烯横向尺寸分布的影响,结果表明后述3个步骤及次序是影响斑点状(横向尺寸<100nm×100nm)和树叶状(横向尺寸>500nm×500nm)还原氧化石墨烯横向尺寸分布的主要因素. 相似文献
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采用改进的Hummers法制备氧化石墨(GO),氧化石墨经高剪切分散乳化机高速剪切处理后进行超声波处理剥离得到氧化石墨烯,然后经水合肼还原得到石墨烯。利用激光粒度仪、扫描电子显微镜(SEM)、X射线衍射仪(XRD)、傅里叶变换红外光谱仪(FT-IR)、热重分析仪(TGA)、激光拉曼光谱仪(Raman)和四探针测试仪等对氧化石墨和石墨烯的形貌及结构进行表征。将高剪切处理制备的石墨烯和未经高剪切处理制备的石墨烯进行对比,结果表明,高速剪切作用对氧化石墨的减薄和剥离有明显促进作用,有利于氧化石墨的还原,提高了石墨烯的制备效率和质量。 相似文献
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目的探究和比较制备石墨烯的两种常见方法,即氧化还原法和液相剥离法。方法采用液相剥离法,在N-甲基吡咯烷酮中超声剥离膨胀石墨制备单层和多层石墨烯,与氧化还原法制备得到的石墨烯在微观形貌和结构表征方面进行比较,并在此基础上比较不同有机溶剂液相剥离制备的石墨烯分散液的浓度和稳定性。结果液相剥离法得到的石墨烯具有更好的片层结构,分子结构含有较少的杂团和含氧基团,石墨烯片层间距较宽,热稳定性更好。在N-甲基吡咯烷酮中液相剥离制备的石墨烯质量浓度可达0.15 mg/m L,稳定性相对较好,该方法在一系列应用中也更易制备导电薄膜和复合材料。结论相较氧化还原法,液相剥离法制备的石墨烯性能更好。 相似文献
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以天然鳞片石墨为原料,氧化插层制备可膨胀石墨,微波热解膨胀后,对膨胀石墨进行二次氧化插层并微波膨胀,采用超声剥离法制备出包含大量少层数碳原子的石墨烯纳米片。采用傅里叶红外光谱(FT-IR)、X射线衍射(XRD)、扫描电镜(SEM)、原子力显微镜(AFM)和拉曼光谱(Raman)对其结构和形貌进行分析。结果表明,氧化插层增大了石墨层间距,膨胀石墨更易于进一步氧化插层引入含氧基团;在微波作用下,石墨内部含氧基团热分解放出气体,进一步增大石墨层间距,甚至部分剥离;对二次膨胀处理的石墨薄片进行超声剥离可得到石墨烯纳米片,大部分石墨烯层数低于5层。 相似文献
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Kim S Zhou S Hu Y Acik M Chabal YJ Berger C de Heer W Bongiorno A Riedo E 《Nature materials》2012,11(6):544-549
Graphene oxide potentially has multiple applications. The chemistry of graphene oxide and its response to external stimuli such as temperature and light are not well understood and only approximately controlled. This understanding is crucial to enable future applications of this material. Here, a combined experimental and density functional theory study shows that multilayer graphene oxide produced by oxidizing epitaxial graphene through the Hummers method is a metastable material whose structure and chemistry evolve at room temperature with a characteristic relaxation time of about one month. At the quasi-equilibrium, graphene oxide reaches a nearly stable reduced O/C ratio, and exhibits a structure deprived of epoxide groups and enriched in hydroxyl groups. Our calculations show that the structural and chemical changes are driven by the availability of hydrogen in the oxidized graphitic sheets, which favours the reduction of epoxide groups and the formation of water molecules. 相似文献
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通过改进石墨烯/银制备过程中的制备温度、pH值以及不同还原剂的选择,研究了反应条件对石墨烯/银复合材料导电性能的影响。结果表明:在氧化石墨烯制备过程中,实验温度对石墨的剥落起到了关键作用,相对于一步法,多步法制备的氧化石墨烯层数更低、纯度更高、导电性能更好;复合过程中pH值的调节能够改变银在氧化石墨烯表面的沉降率,当pH值为12时,银的沉降密度最大,产物的电导率更高,达5.3×10~2 S/m;在进行氧化石墨烯材料的还原时,同等条件下,NaBH_4的还原效果要优于柠檬酸三钠和Vc的还原效果,经NaBH_4还原的r GO和rGO/Ag的电导率分别为0.46×10~4,7.32×10~4 S/m,且经NaBH_4还原的rGO/Ag制备的导电油墨,具有与商业导电银浆相媲美的电阻值。 相似文献
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MXenes作为一种新兴的二维层状过渡金属碳化物、氮化物和碳氮化合物, 近年来被广泛应用于物理、化学、材料科学和纳米技术领域当中。MXenes制备过程中会不可避免地出现缺陷和—O, —OH, —F官能团, 同时具备高的电导率和大的比表面积, 使得MXenes具有良好的电子转移速率, 可作为一种优良的电化学催化剂。本文综述了MXenes在电催化领域的研究进展, 介绍了MXenes多种合成方法、不同掺杂类型的发展现状, 重点讨论了其在电催化产氢、产氧、氧气还原、CO2还原以及氮气还原过程中的应用及机理研究, 并指出目前MXenes制备方法应朝着环境友好、形貌可控、难以氧化和高的可调节性方向发展, 以便应用于不同的电催化反应中。 相似文献
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目的设计一种能提高一次剥净率、降低果肉破损率的柑橘自动剥皮设备。方法提出一种多方法融合创新设计模型,并将其应用于柑橘自动剥皮设备的创新设计中。首先,根据Kano模型得到柑橘自动剥皮设备的用户需求属性;然后,结合公理设计理论完成域间映射,得到设计矩阵;由独立公理判断出设计矩阵类型,得到设计矩阵是准耦合设计,运用TRIZ理论进行解耦设计,得到柑橘自动剥皮机的创新设计方案;最后,结合层次分析法和模糊综合评价法对设计方案进行评价。结果利用该创新设计模型得到的柑橘自动剥皮机创新设计方案,在功能属性、安全属性和经济属性等3个方面都要优于现有的柑橘自动剥皮设备。结论设计的柑橘自动剥皮设备满足设计要求,验证了该创新设计模型的可行性及合理性。 相似文献
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Hyun Kyu Shin Si Woon Lee Goo Pyo Hong Lee Sael Sang Hyo Lee Ha Young Kim 《计算机、材料和连续体(英文)》2021,66(3):2493-2507
The demand for defect diagnoses is gradually gaining ground owing to the growing necessity to implement safe inspection methods to ensure the durability and quality of structures. However, conventional manpower-based inspection methods not only incur considerable cost and time, but also cause frequent disputes regarding defects owing to poor inspections. Therefore, the demand for an effective and efficient defect-diagnosis model for concrete structures is imminent, as the reduction in maintenance costs is significant from a long-term perspective. Thus, this paper proposes a deep learning-based image object-identification method to detect the defects of paint peeling, leakage peeling, and leakage traces that mostly occur in underground parking lots made of concrete structures. The deep learning-based object-detection method can replace conventional visual inspection methods. A faster region-based convolutional neural network (R-CNN) model was used with a training dataset of 6,281 images that utilized a region proposal network to objectively localize the regions of interest and detect the surface defects. The defects were classified according to their type, and the learning of each exclusive model was ensured through test sets obtained from real underground parking lots. As a result, average precision scores of 37.76%, 36.42%, and 61.29% were obtained for paint peeling, leakage peeling, and leakage trace defects, respectively. Thus, this study verified the performance of the faster RCNN-based defect-detection algorithm along with its applicability to underground parking lots. 相似文献
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将石墨烯加入到富锌涂料中能增强锌粉对基体铁板的"阴极保护"效应,但目前关于氧化石墨烯还原程度对涂料性能的影响研究不多。以通用的hummers法制备氧化石墨烯(GO),通过控制还原时间,得到不同还原程度的还原-氧化石墨烯(r GO)。以拉曼光谱、X射线衍射等表征手段测定r GO的还原程度。结果显示:还原12 h之后还原程度基本不变。将几组不同还原程度的r GO用于改性环氧富锌涂料得到r GO改性富锌涂料并制备涂层,通过盐雾试验、铁离子浓度测定、Tafel极化曲线测试等研究了r GO还原程度对防腐蚀涂料涂层防腐蚀性能的影响,并与未加石墨烯的环氧富锌涂料对比。结果表明:加入少量还原程度较低的r GO能提高含锌量86%传统富锌涂料涂层的防腐蚀性能;还原6 h即还原程度为58%的r GO改性富锌涂料涂层的防腐蚀性能最佳。 相似文献
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N. I. Baklanova T. M. Zima A. T. Titov N. V. Isaeva D. V. Grashchenkov S. S. Solntsev 《Inorganic Materials》2006,42(7):744-749
Protective refractory nanocoatings on carbon bundles and tapes have been investigated. Processes have been developed for growing thin layers of refractory oxides—alumina, zirconia, and silica—on continuous carbon fibers and tapes using sol-gel processing. ZrC/ZrO2 bilayer coatings have been produced by chemical vapor transport. The surface morphology, phase composition, and elemental composition of the coatings have been studied by x-ray diffraction, high-resolution scanning electron microscopy, and qualitative energy-dispersive x-ray microanalysis. The results demonstrate that the refractory oxide coatings are homogeneous along the length and perimeter of individual fibers and adhere well to the fiber surface, with no peeling. Their thickness is within 200–300 nm. The effect of the nature of the coating on the oxidation resistance of carbon materials is analyzed. 相似文献