共查询到20条相似文献,搜索用时 78 毫秒
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利用镍纳米粒子修饰石墨烯(GPLs)制备石墨烯镍纳米粒子复合物(Ni-GPLs);将复合物作为增强相作用于Cu基体(NiGPLs-Cu),研究其力学性能;采用SEM、TEM、XRD、FT-IR和XPS等对Ni-GPLs进行表征。结果表明:Ni-GPLs由附着在GPLs上且分散均匀的镍纳米颗粒构成,镍离子通过化学还原在GPLs表面合成Ni-GPLs;含有体积分数为0.8%Ni-GPLs的Ni-GPL-Cu复合材料的极限抗拉强度(UTS)显著提高,比纯Cu的高出42%,大大提高Ni-GPLs-Cu的力学性能。 相似文献
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采用微波-乙二醇方法还原氧化石墨烯和Pt(v)、Co(Ⅱ)粒子混合物,再经300℃H2还原,制备了石墨烯负载Pt-Co合金催化剂(Pt-Co/G).利用透射电镜、X-射线能谱、X-射线衍射和光电子能谱对所制催化剂进行表征.Pt-Co合金的粒径为3nm~8 nm,均匀地分散在石墨烯片上.与单金属的Pt/G和商品化的Pt/C催化剂相比,所制合金化的Pt-Co/G催化剂对氧还原反应展现出高的催化活性和可比拟的稳定性,显示了其在燃料电池中的应用潜力. 相似文献
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石墨烯及其衍生物作为二维碳纳米材料可以有效地结合金属、半导体纳米粒子,同时,石墨烯及其衍生物与有机功能分子之间也可以通过共价或以π-π、静电等非共价形式发生相互作用。简述了石墨烯纳米复合材料的基本结构、制备策略、电子储存与转移以及能量传递特性,讨论了石墨烯纳米复合材料在光、电催化、电化学太阳能电池等领域中的研究应用进展。 相似文献
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为解决纳米银催化剂易团聚的问题,选择三维还原氧化石墨烯(3D-rGO)作为载体材料,采用一步绿色水热法制备了纳米银/三维还原氧化石墨烯(Ag/3D-rGO)复合材料,采用SEM、XRD、FTIR、Raman、XPS等方法对材料的形貌和结构进行了系统的表征,并在室温下以对硝基苯酚(4-NP)的催化还原反应为模型,考察了所得复合材料的催化性能。结果表明,成功制备出了Ag/3D-rGO纳米复合材料,材料内部呈3D多孔网络结构,Ag纳米颗粒均匀附着在孔壁表面,颗粒的平均粒径为67 nm,无明显团聚;Ag/3D-rGO纳米复合材料可以在2 min内实现4-NP的催化还原,该催化反应过程遵循一级催化动力学反应规律,对应的一级催化动力学常数为1.8694 min-1,高于现有报道中同类材料。研究的材料制备方法简便,催化性能优异,在工业催化和环境保护领域具有广阔的应用前景。 相似文献
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石墨烯作为一种由单原子紧密堆积成的二维蜂窝状晶格结构碳材料,具有许多特殊的物理化学性质,使其在各个领域均表现出良好的应用前景。目前石墨烯及纳米石墨烯复合材料的制备和应用已成为材料界研究的重点和热点。在简要介绍石墨烯的结构和性质的基础上,介绍了石墨烯的4种制备方法——机械剥离法、化学气相沉积法、化学剥离法和化学合成法。总结了纳米石墨烯/聚合物复合材料以及纳米无机/石墨烯复合材料的制备及应用,并重点讨论了纳米石墨烯复合材料在生物医药、电子器件、微波吸收、传感器以及电极材料等方面独特的应用优势,展望了纳米石墨烯复合材料的发展前景及研究方向。 相似文献
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Ulises Martinez Siddharth Komini Babu Edward F. Holby Hoon T. Chung Xi Yin Piotr Zelenay 《Advanced materials (Deerfield Beach, Fla.)》2019,31(31)
Development of alternative energy sources is crucial to tackle challenges encountered by the growing global energy demand. Hydrogen fuel, a promising way to store energy produced from renewable power sources, can be converted into electrical energy at high efficiency via direct electrochemical conversion in fuel cells, releasing water as the sole byproduct. One important drawback to current fuel‐cell technology is the high content of platinum‐group‐metal (PGM) electrocatalysts required to perform the sluggish oxygen reduction reaction (ORR). Addressing this challenge, remarkable progress has been made in the development of low‐cost PGM‐free electrocatalysts synthesized from inexpensive, earth‐abundant, and easily sourced materials such as iron, nitrogen, and carbon (Fe–N–C). PGM‐free Fe–N–C electrocatalysts now exhibit ORR activities approaching that of PGM electrocatalysts but at a fraction of the cost, promising to significantly reduce overall fuel‐cell technology costs. Herein, recent developments in PGM‐free electrocatalysis, demonstrating increased fuel‐cell performance, as well as efforts aimed at understanding the key limiting factor, i.e., the nature of the PGM‐free active site, are summarized. Further improvements will be accomplished through the controlled and/or rationally designed synthesis of materials with higher active‐site densities, while at the same time establishing methods to mitigate catalyst degradation. 相似文献
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Graphene/Graphene‐Tube Nanocomposites Templated from Cage‐Containing Metal‐Organic Frameworks for Oxygen Reduction in Li–O2 Batteries 下载免费PDF全文
Qing Li Ping Xu Wei Gao Shuguo Ma Guoqi Zhang Ruiguo Cao Jaephil Cho Hsing‐Lin Wang Gang Wu 《Advanced materials (Deerfield Beach, Fla.)》2014,26(9):1378-1386
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采用脲、硼酸、硝酸铁、硝酸钴分别作为N、B、Fe、Co源,与GO(氧化石墨烯)通过快速冷冻干燥与热解法,制得了三维石墨烯基B-N-Fe/Co-G催化材料,并对其结构和性能进行了测试和表征,研究其氧还原的活性物质与活性点。透射电子显微镜(TEM)、扫描电子显微镜(SEM)、拉曼光谱(Raman)、X射线衍射(XRD)及X射线光电子能谱(XPS)结果显示,所制得掺杂石墨烯表面褶皱呈三维孔洞结构,掺杂原子N、B、Fe、Co均匀掺杂于石墨烯中。通过循环伏安法(CV)、线性扫描伏安法(LSV)等手段对三维石墨烯基B-N-Fe/Co-G催化材料进行电化学性能测试,结果表明:B-N-Fe/Co-G在0.1 mol/L的 KOH碱性电解质中有较高的氧还原(ORR)催化活性,起始电位在1.0 V左右,为4电子转移,相比质量分数20%的商用Pt/C催化剂有更好的电化学稳定性。 相似文献
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Nitrogen‐Coordinated Single Cobalt Atom Catalysts for Oxygen Reduction in Proton Exchange Membrane Fuel Cells 下载免费PDF全文
Xiao Xia Wang David A. Cullen Yung‐Tin Pan Sooyeon Hwang Maoyu Wang Zhenxing Feng Jingyun Wang Mark H. Engelhard Hanguang Zhang Yanghua He Yuyan Shao Dong Su Karren L. More Jacob S. Spendelow Gang Wu 《Advanced materials (Deerfield Beach, Fla.)》2018,30(11)
Due to the Fenton reaction, the presence of Fe and peroxide in electrodes generates free radicals causing serious degradation of the organic ionomer and the membrane. Pt‐free and Fe‐free cathode catalysts therefore are urgently needed for durable and inexpensive proton exchange membrane fuel cells (PEMFCs). Herein, a high‐performance nitrogen‐coordinated single Co atom catalyst is derived from Co‐doped metal‐organic frameworks (MOFs) through a one‐step thermal activation. Aberration‐corrected electron microscopy combined with X‐ray absorption spectroscopy virtually verifies the CoN4 coordination at an atomic level in the catalysts. Through investigating effects of Co doping contents and thermal activation temperature, an atomically Co site dispersed catalyst with optimal chemical and structural properties has achieved respectable activity and stability for the oxygen reduction reaction (ORR) in challenging acidic media (e.g., half‐wave potential of 0.80 V vs reversible hydrogen electrode (RHE). The performance is comparable to Fe‐based catalysts and 60 mV lower than Pt/C ‐60 μg Pt cm?2). Fuel cell tests confirm that catalyst activity and stability can translate to high‐performance cathodes in PEMFCs. The remarkably enhanced ORR performance is attributed to the presence of well‐dispersed CoN4 active sites embedded in 3D porous MOF‐derived carbon particles, omitting any inactive Co aggregates. 相似文献