共查询到20条相似文献,搜索用时 62 毫秒
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材料表面抗反射性能在太阳能利用、光电子产品、红外传感和成像、军事隐身、以及航空航天等领域均具有重要应用价值。文中对材料表面抗反射特性的重要用途、人工实现路径、表面抗反射结构的研究现状及存在的问题等做了详细的论述。目前,国内外学者已经利用碳纳米管涂层和硅表面针状纳米结构实现了优异的超宽波谱抗反射性能。但迄今为止,金属表面微纳米结构的抗反射能力仍有很大的改善空间。作者所在的清华大学材料学院激光加工研究团队运用新一代高功率高频率超快激光,在金属表面制备出多种类型的特征微纳米结构,对其抗反射性能进行系统研究,实现了紫外-可见、紫外-近红外、紫外-中红外与紫外-远红外分别为2%、6%、5%和8%的超宽光谱超低反射率,并且在0~60入射角度范围内无明显变化。进一步在微纳米结构基础上发展了宏-微纳-纳米线多级多尺度复合结构,在16~17m波长处的总反射率低至0.6%,在14~18m波长处总反射率不超过3%。上述优异超宽光谱抗反射性能预期具有良好应用前景。 相似文献
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一种将激光与近场技术结合的方法在制备分辨率达10nm的金属纳米结构中取得成功。据信这将是能用激光制备的最小尺寸。这项技术能广泛应用于从数据存储到在生物技术中用“纳米刀”修改大分子(图1)。图1这张欧洲地图是用激光绘在金基底上的德国激光技术实验室发展了一种顶端近场的激光辐射聚焦技术,称为FOLANT。这项技术为激光在高信息密度的数字信号载体,半导体掩膜的修复和光谱学领域的应用提供了许多可能性。目前它已用于制备纳米结构的材料并有希望在斐涅尔光学件生产中得到应用。到目前为止,这种“把激光作为一项工具”在发展纳… 相似文献
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激光表面熔覆制备纳米结构涂层的研究进展 总被引:8,自引:1,他引:8
激光表面熔覆制备纳米结构涂层是一种新型的纳米表面涂层技术.综述了国内外近年来激光熔覆制备纳米结构涂层的研究进展.从熔覆对象的角度介绍了激光熔覆制备纳米结构涂层的主要技术,熔覆对象可分为纳米粉末和预制纳米结构涂层.而纳米粉末主要有纯纳米粉末、纳米/微米混合粉末和构造纳米粉末等;预制纳米结构涂层可分为热喷涂纳米结构涂层、纳米复合镀层以及溶胶一凝胶(sol-gel)纳米结构涂层等.阐述了激光熔覆制备纳米结构涂层存在的主要问题,并提出了当前的主要发展趋势:激光熔覆原位生成纳米结构涂层、激光熔覆纳米/微米构造复合粉末以及激光熔覆制备纳米结构涂层过程的数值模拟等. 相似文献
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自然界中的微纳结构蕴藏着无尽的功能,为材料科学和工程技术的创新与发展带来了新的机遇。受生物体功能表面的启发,针对仿生表面开发出大量新功能,如结构色、超疏水、自清洁、光学性能调控等。飞秒激光制造是一种可以在微米和纳米尺度上精确控制材料结构的加工方式。通过调控飞秒激光加工参数,可以在多种材料体系中实现超越衍射极限的三维加工。飞秒激光直写加工技术的独特之处在于可以实现材料的跨尺度修饰,通过模拟优化,制备更加复杂的微纳结构。综述了利用飞秒激光技术制备仿生功能微纳结构的新进展,展示了该结构在结构色、表面浸润性、光学性能调控等方面的性能。讨论了飞秒激光制备仿生功能表面的应用前景。最后举例说明了激光微纳制造复杂高分辨率结构的新应用。 相似文献
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微纳米颗粒的去除是半导体、微电子、微型机械、精密光学等高新技术中的关键问题,而常规清洗方法难以有效去 除。近年来国际上发展的DLC、SLC激光去除方法非常有效,本文对DLC、SLC的实验方法、去除机制、影响因素和规律等进 行综述,指出了存在的问题。 相似文献
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为了解决厨房用开关面板抗油污沉积的问题, 采用飞秒激光在开关面板表面制备出微纳米复合结构表面, 实现了超疏水性, 进而减少油污沉积附着, 研究了聚碳酸酯(PC)开关面板的激光烧蚀阈值、不同激光工艺参数和微纳结构对表面浸润性的影响。结果表明, PC开关面板在515nm波段下的烧蚀阈值为1.66μJ; 当激光能量为1.6μJ、扫描速率为200mm/s、搭接率为1/3线宽时, 其表面液滴接触角为161°, 表现出超疏水特性。经激光表面处理后的PC面板具有超疏水性, 可实现表面的自清洁作用, 显示出巨大的市场潜力。 相似文献
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自然界中存在大量具有特殊微纳结构的多尺度表面,如荷叶、水稻叶、玫瑰花瓣、壁虎脚趾、鲨鱼皮、蝴蝶翅膀、昆虫复眼等,这些表面具有超疏水、超亲水、结构色、高敏感性、生物相容性等多种神奇功能。如何人工制备出仿生微纳米结构,从而实现师法自然和超越自然的目标,是材料与制造领域的重大课题之一。超快激光加工是灵活制备微纳米结构的可靠手段,但衍射极限制约了其纳米结构制备能力,且制备效率低下。本团队在过去的10多年中,在拓展超快激光微米与纳米结构制备能力以及仿生微纳结构的功能化方面开展了系统研究,发展了一系列超快激光微纳结构制备与双级精确调控新方法,探索了超快激光制备的微纳结构表面在超疏水、高抗反射、高敏感性和生物医学检测等领域的创新应用。超快激光制备形态多样的微纳米结构并实现仿生功能化是一个富有吸引力的研究方向,但仍然面临着诸如突破衍射极限以实现1~100 nm典型纳米结构的制备、功能化微纳结构的设计与制备以及大面积微纳结构的高效制备等挑战。本文为《清华大学建校110周年之光耀清华》专辑而撰写,旨在总结过去、面向未来,与本领域同仁一起交流探讨,共同推进本研究领域的发展。 相似文献
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超疏水自清洁荷叶结构表面有重要应用潜力。运用高功率皮秒激光结合高速扫描振镜,在H13模具钢表面高效制备了密排六方点阵微米级凹坑,其中含有丰富的纳米级亚结构,获得了面积为25mm×25mm的反荷叶结构。将该结构用于超疏水微纳米压印模板,在165℃、6MPa、大气环境中进行硅橡胶压印,获得大面积微米级突起阵列,表面分布着纳米级亚结构,与荷叶结构十分相似。压印后硅橡胶表面接触角达到153.3°,接触角滞后值为3.2°,实现了超疏水性。皮秒激光制备的模板能进行连续压印,具有一定的耐久性和连续压印能力。 相似文献
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Zexing Wu Ying Zhao Hengbo Wu Yuxiao Gao Zhi Chen Wei Jin Jinsong Wang Tianyi Ma Lei Wang 《Advanced functional materials》2021,31(17):2010437
Exploiting highly effective and low-cost electrocatalysts for the hydrogen evolution reaction (HER) is a pressing challenge for the development of sustainable hydrogen energy. In this work, a facile and industrially compatible one-pot corrosion strategy for the rapid synthesis of amorphous RuO2-decorated FeOOH nanosheets on iron foam (FF Na Ru) within 1 h is reported. Corrosion is a common and inevitable phenomenon that occurs on metal surfaces without electricity input, high temperature, and tedious synthetic procedures. The FF Na Ru electrode is superhydrophilic and aerophobic, which guarantees intimate contact with the electrolyte and accelerates the instantaneous escape of produced gas bubbles during the electrocatalytic process. Moreover, the strong electronic interactions between RuO2 and FeOOH promote the electrocatalytic process via dramatically improving the electrochemical interfacial properties. Thus, the FF Na Ru electrocatalyst presents excellent catalytic activity towards the HER (30 mV at 10 mA cm–2) and overall water-splitting (230 mV at 10 mA cm–2) in 1 M KOH. The overall water-splitting could be simply powered by sustainable and intermittent sunlight, wind, and thermal energies motivated Stirling engine. Density functional theory calculations confirm that coupling effects between RuO2 and FeOOH are also responsible for promoting the electrocatalytic HER performance. 相似文献
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Efficient and Stable Bifunctional Electrocatalysts Ni/NixMy (M = P,S) for Overall Water Splitting 下载免费PDF全文
Gao‐Feng Chen Tian Yi Ma Zhao‐Qing Liu Nan Li Yu‐Zhi Su Kenneth Davey Shi‐Zhang Qiao 《Advanced functional materials》2016,26(19):3314-3323
Development of easy‐to‐make, highly active, and stable bifunctional electrocatalysts for water splitting is important for future renewable energy systems. Three‐dimension (3D) porous Ni/Ni8P3 and Ni/Ni9S8 electrodes are prepared by sequential treatment of commercial Ni‐foam with acid activation, followed by phosphorization or sulfurization. The resultant materials can act as self‐supported bifunctional electrocatalytic electrodes for direct water splitting with excellent activity toward oxygen evolution reaction and hydrogen evolution reaction in alkaline media. Stable performance can be maintained for at least 24 h, illustrating their versatile and practical nature for clean energy generation. Furthermore, an advanced water electrolyzer through exploiting Ni/Ni8P3 as both anode and cathode is fabricated, which requires a cell voltage of 1.61 V to deliver a 10 mA cm?2 water splitting current density in 1.0 m KOH solution. This performance is significantly better than that of the noble metal benchmark—integrated Ni/IrO2 and Ni/Pt–C electrodes. Therefore, these bifunctional electrodes have significant potential for realistic large‐scale production of hydrogen as a replacement clean fuel to polluting and limited fossil‐fuels. 相似文献
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Bifunctional Nickel Phosphide Nanocatalysts Supported on Carbon Fiber Paper for Highly Efficient and Stable Overall Water Splitting 下载免费PDF全文
Xiaoguang Wang Wei Li Dehua Xiong Dmitri Y. Petrovykh Lifeng Liu 《Advanced functional materials》2016,26(23):4067-4077
Self‐supported electrodes comprising carbon fiber paper (CP) integrated with bifunctional nickel phosphide (Ni‐P) electrocatalysts are fabricated by electrodeposition of Ni on functionalized CP, followed by a convenient one‐step phosphorization treatment in phosphorus vapor at 500 °C. The as‐fabricated CP@Ni‐P electrode exhibits excellent electrocatalytic performance toward hydrogen evolution in both acidic and alkaline solutions, with only small overpotentials of 162 and 250 mV, respectively, attaining a cathodic current density of 100 mA cm?2. Furthermore, the CP@Ni‐P electrode also exhibits superior catalytic performance toward oxygen evolution reaction (OER). An exceptionally high OER current of 50.4 mA cm?2 is achieved at an overpotential of 0.3 V in 1.0 m KOH. The electrode can sustain 10 mA cm?2 for 180 h with only negligible degradation, showing outstanding durability. Detailed microstructural and compositional studies reveal that upon OER in alkaline solution the surface Ni‐P is transformed to NiO covered with a thin Ni(OH)x layer, forming a Ni‐P/NiO/Ni(OH)x heterojunction, which presumably enhances the electrocatalytic performance for OER. Given the well‐defined bifunctionality, a full alkaline electrolyzer is constructed using two identical CP@Ni‐P electrodes as cathode and anode, respectively, which can realize overall water splitting with efficiency as high as 91.0% at 10 mA cm?2 for 100 h. 相似文献
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Jagadis Gautam Yi Liu Jie Gu Zhiyuan Ma Junjie Zha Bipeen Dahal Lu-Nan Zhang Aadil Nabi Chishti Lubin Ni Guowang Diao Yongge Wei 《Advanced functional materials》2021,31(46):2106147
The advancement of a naturally rich and effective bifunctional substance for hydrogen and oxygen evolution reaction is crucial to enhance hydrogen fuel production efficiency via the electrolysis process. Herein, facile and scalable hydrothermal synthesis of bifunctional electrocatalyst of polyoxometalate anchored zinc cobalt sulfide nanowire on Ni-foam (NF) for overall water splitting is reported for the first time. The electrochemical analysis of POM@ZnCoS/NF displays significantly low HER and OER overpotentials of 170/337 and 200/300 mV to attain a current density of 10/40 and 20/50 mA cm−2, respectively, demonstrating the notable performance of POM@ZnCoS/NF toward H2 and O2 evolution reaction in alkaline medium. Additionally, the electrolyzer consisting of the POM@ZnCoS/NF anode and cathode shows an appealing potential of 1.56 V to deliver 10 mA cm−2 current density for overall water splitting. The high electrocatalytic activity of the POM@ZnCoS/NF is attributed to modulation of the electronic and chemical properties, increment of the electroactive sites and electrochemically active surface area of the zinc cobalt sulfide nanowires due to the anchorage of polyoxometalate nanoparticles. These results demonstrate the advantage of the polyoxometalate incorporation strategy for the design of cost-effective and highly competent bifunctional catalysts for complete water splitting. 相似文献
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Bifunctional Porous NiFe/NiCo2O4/Ni Foam Electrodes with Triple Hierarchy and Double Synergies for Efficient Whole Cell Water Splitting 下载免费PDF全文
A 3D hierarchical porous catalyst architecture based on earth abundant metals Ni, Fe, and Co has been fabricated through a facile hydrothermal and electrodeposition method for efficient oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). The electrode is comprised of three levels of porous structures including the bottom supermacroporous Ni foam (≈500 μm) substrate, the intermediate layer of vertically aligned macroporous NiCo2O4 nanoflakes (≈500 nm), and the topmost NiFe(oxy)hydroxide mesoporous nanosheets (≈5 nm). This hierarchical architecture is binder‐free and beneficial for exposing catalytic active sites, enhancing mass transport and accelerating dissipation of gases generated during water electrolysis. Serving as an anode catalyst, the designed hierarchical electrode displays excellent OER catalytic activity with an overpotential of 340 mV to achieve a high current density of 1200 mA cm?2. Serving as a cathode catalyst, the catalyst exhibits excellent performance toward HER with a moderate overpotential of 105 mV to deliver a current density of 10 mA cm?2. Serving as both anode and cathode catalysts in a two‐electrode water electrolysis system, the designed electrode only requires a potential of 1.67 V to deliver a current density of 10 mA cm?2 and exhibits excellent durability in prolonged bulk alkaline water electrolysis. 相似文献
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Hang Shi Xin-Ying Sun Yang Liu Shu-Pei Zeng Qing-Hua Zhang Lin Gu Tong-Hui Wang Gao-Feng Han Zi Wen Qian-Rong Fang Xing-You Lang Qing Jiang 《Advanced functional materials》2023,33(19):2214412
Developing high-efficiency and cost-effective alloy catalysts toward hydrogen-evolution reaction (HER) is crucial for large-scale hydrogen production via electrochemical water splitting, but conventional single-principal-element alloy design usually causes insufficient activity and durability of state-of-the-art multimetallic catalysts based on non-precious transition metals. Herein, we report multicomponent intermetallic Mo(NiFeCo)4 nanoparticles seamlessly integrated on hierarchical nickel network (Mo(NiFeCo)4/Ni) as robust hydrogen-evolution electrocatalysts with remarkably improved activity and durability by making use of iron and cobalt atoms partially substituting nickel sites to form high-entropy NiFeCo sublattice in intermetallic MoNi4 matrix, which serve as bifunctional electroactive sites for both water dissociation and adsorption/combination of hydrogen intermediate and improves thermodynamic stability. By virtue of bicontinuous nanoporous nickel skeleton facilitating electron/ion transportation, self-supported nanoporous Mo(NiFeCo)4/Ni electrode exhibits exceptional HER electrocatalysis, with low Tafel slope (≈35 mV dec−1), high current density (≈2300 mA cm−2) at low overpotential (200 mV) and long-term durability in 1 m KOH. When coupled to its electrooxidized and nitrified derivative for oxygen-evolution reaction, their alkaline water electrolyzers operate with a superior overall water-splitting output, outperforming the one constructed with commercially available noble-metal-based catalysts. These electrochemical properties make it an attractive candidate as electrocatalyst in alkaline water electrolysis for large-scale hydrogen generation. 相似文献
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Hang Shi Tian-Yi Dai Wu-Bin Wan Zi Wen Xing-You Lang Qing Jiang 《Advanced functional materials》2021,31(28):2102285
Designing robust and cost-effective electrocatalysts based on Earth-abundant elements is crucial for large-scale hydrogen production through electrochemical water splitting. Here, nitrogen-doped carbon engrafted Mo2N/CoN hybrid nanosheets that are seamlessly oriented on hierarchical nanoporous Cu scaffold (Mo-/Co-N-C/Cu), as highly efficient electrocatalysts for alkaline hydrogen evolution reaction are reported. The constituent heterostructured Mo2N/CoN nanosheets work as bifunctional electroactive sites for both water dissociation and adsorption/desorption of hydrogen intermediates while the nitrogen-doped carbon bridges electron transfers between electroactive sites and interconnective Cu current collectors by making use of Mo-/Co-N-C bonds and intimate C/Cu contacts at interfaces. As a consequence of unique architecture having electroactive sites to be sufficiently accessible, self-supported nanoporous Mo-/Co-N-C/Cu hybrid electrodes exhibit outstanding electrocatalysis in 1 m KOH, with a negligible onset overpotential and a low Tafel slope of 47 mV dec−1. They only take overpotential of as low as 230 mV to reach current density of 1000 mA cm−2. When coupled with their electro-oxidized derivatives that mediate efficiently the oxygen evolution reaction, the alkaline water electrolyzer can achieve ≈100 mA cm−2 at 1.622 V in 1 m KOH electrolyte, ≈0.343 V lower than the device constructed with commercially available Pt/C and Ir/C nanocatalysts immobilized on nanoporous Cu electrodes. 相似文献
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Jungang Hou Yunzhen Wu Bo Zhang Shuyan Cao Zhuwei Li Licheng Sun 《Advanced functional materials》2019,29(20)
Electrochemical water splitting is recognized as a practical strategy for impelling the transformation of sustainable energy sources such as solar energy from electricity to clean hydrogen fuel. To actualize the large‐scale hydrogen production, it is paramount to develop low‐cost, earth‐abundant, efficient, and stable electrocatalysts. Among those electrocatalysts, alternative architectural arrays grown on conductive substrates have been proven to be highly efficient toward water splitting due to large surface area, abundant active sites, and synergistic effects between the electrocatalysts and the substrates. Herein, the advancement of nanoarray architectures in electrocatalytic applications is reviewed. The categories of different nanoarrays and the reliable and versatile synthetic approaches of electrocatalysts are summarized. A unique emphasis is highlighted on the promising strategies to enhance the electrocatalytic activities and stability of architectural arrays by component manipulation, heterostructure regulation, and vacancy engineering. The intrinsic mechanism analysis of electronic structure optimization, intermediates' adsorption facilitation, and coordination environments' amelioration is also discussed with regard to theoretical simulation and in situ identification. Finally, the challenges and opportunities on the valuable directions and promising pathways of architectural arrays toward outstanding electrocatalytic performance are provided in the energy conversion field, facilitating the development of promising water splitting systems. 相似文献
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Xiaodong Shao Mengfang Liang Min Gyu Kim Sara Ajmal Ashwani Kumar Xinghui Liu Hyun Seung Jung Haiyan Jin Fengliang Cao Jianmin Yu Kim My Tran Hyun Ko Jinsun Lee Jong Wook Bae Hyoyoung Lee 《Advanced functional materials》2023,33(12):2211192
Reducing the particle sizes of transition metals (TMs) and avoiding their aggregation are crucial for increasing the TMs atom utilization and enhancing their industrial potential. However, it is still challenging to achieve uniform distributed and density-controlled TMs nanoclusters (NCs) under high temperatures due to the strong interatomic metallic bonds and high surface energy of NCs. Herein, a series of TMs NCs with controllable density and nitrogen-modulated surface are prepared with the assistance of a selected covalent organic polymer (COP), which can provide continuous anchoring sites and size-limited skeletons. The prepared Ir NCs show superior hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) activities than commercial Pt/C and Ir/C in both acid and alkaline media. In particular, the as-prepared Ir NCs exhibit remarkable full water splitting performance, reaching a current density of 10 mA cm−2 at ultralow overpotentials of 1.42 and 1.43 V in alkaline and acidic electrolyte, respectively. The excellent electrocatalytic activities are attributed to the increased surface atom utilization and the improved intrinsic activity of Ir NCs. More importantly, the Ir NCs catalyst shows superior long-term stability due to the strong interaction between Ir NCs and the N-doped carbon layer. 相似文献