检索结果-南通市图书馆

Edge dislocation-induced strains break the limit of PtNi alloys in boosting Pt mass activity for efficient alkaline hydrogen evolution

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第6期17卷 4711-4719页

作者： Miao Zhou Yao Zhao Zhanwei Liu Xueru Zhao Enzuo Liu Liyang Xiao Pengfei Yin Cunku Dong Hui Liu xiwen du Jing Yang New Energy Materials Institute School of Materials Science and EngineeringTianjin UniversityTianjin 300072China School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Chemistry Division Brookhaven National LaboratoryUptonNew York 11973USA Advanced Metallic Materials Institute School of Materials Science and EngineeringTianjin UniversityTianjin 300072China

Creating lattice defects and alloying to produce strain effect in Pt-based bimetallic alloys are both effective methods to optimize the crystal and electronic structure and improve the electrocatalytic ***,the principles that govern the alkaline hydrogen evolution reaction(HER)performance remain unclear,which is detrimental to the rational design of efficient Pt-based ***,PtNi alloys with different Pt/Ni ratios and edge dislocations were synthesized,and the effects of Pt/Ni composition and edge dislocations on the alkaline HER electrocatalytic activity of PtNi alloys were systematically *** experimental and theoretical investigations reveal that tuning Pt/Ni ratio results in only 1.1 times enhancements in Pt mass activity,whereas edge dislocations-induced extra tensile strain on Ni site and compressive strain on Pt site further boost the alkaline HER intrinsic activity at all Pt/Ni ***,the introduction of edge dislocations in PtNi alloys could break the limit of alloying in boosting Pt mass activity and result in up to 13.7-fold enhancement,in the case that Pt and Ni contents are nearly identical and thus edge dislocation density reaches the *** mechanism studies demonstrate that the edge dislocation strategy could make a breakthrough in facilitating water dissociation kinetics of PtNi alloys.

关键词： edge dislocations PtNi composition strain effects water dissociation hydrogen evolution reaction

Mechanically mixing copper and silver into self-supporting electrocatalyst for hydrogen evolution

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2023年第10期30卷 1906-1913页

作者： Xinzhuo Hu Zhe Liu Yi Feng Yongfeng Zhang Zhe Li Zhennan Chen Jing Mao Jing Yang Hui Liu Pengfei Yin Lei Cui xiwen du Institute of New Energy Materials School of Materials Science and EngineeringTianjin UniversityTianjin 300072China Institute of Advanced Welding Technology School of Materials Science and EngineeringTianjin UniversityTianjin 300072China Zijin Copper Co.LTD.Shanghang Country Longyan 364200China Department of Materials Science Fudan UniversityShanghai 200433China

Commercial hydrogen production involves the development of efficient hydrogen evolution reaction ***,we adopted a friction stir processing(FSP)technique to mix immiscible metals homogenously and obtain a self-supporting copper-silver(CuAg)*** gust of Ag atoms with larger atomic sizes caused a tensile strain in the Cu ***,the chemical-potential difference induced electron transfer from Cu to Ag,and the two factors jointly led to the upshift of Cu d-band and improved the catalytic ***,the CuAg electrode exhibited a high turnover frequency(12 times that of pure Cu),a low overpotential at high current density(superior to platinum foil),and high durability(1.57%decay over 180 h).Our work demonstrates that FSP is a powerful method for preparing self-supporting catalysts of immiscible alloys with high catalytic performance.

关键词： hydrogen evolution reaction catalyst friction stir processing strain electron transfer

A Rational Design of Heterojunction Photocatalyst Cd S Interfacing with One Cycle of ALD Oxide

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2016年第6期32卷 489-495页

作者： Mengyin Liu Xinjian Xie Lei Chen Xuewei Wang Yahui Cheng Feng Lu Wei-Hua Wang Jing Yang xiwen du Junda Zhu Haitao Liu Hong Dong Weichao Wang Hui Liu Department of Electronics and Key Laboratory of Photo-Electronic Thin Film Devices and Technology of Tianjin Nankai University School of Material Science and Engineering Hebei University of Technology Institute of Material Physics Key Laboratory of Display Materials and Photoelectric DevicesTianjin University of Technology Tianjin Key Laboratory of Composite and Functional Materials and School of Materials Science and Engineering Tianjin University Key Laboratory of Optical Information Science and Technology Ministry of EducationInstitute of Modern OpticsNankai University

Photo-corrosion is one of the major obstacles for CdS application in wet chemical fields, and atomic layer deposition （ALD） has been proposed as an effective way to suppress the corrosion. Here, prior to ALD coating, CdS, one facilely corrosive photocatalyst, was synthesized via hydrothermal synthesis to access the fundamental corrosion mechanism and the according corrosive sites. X-ray photoelectron spectros- copy （XPS） and X-ray diffraction （XRD） demonstrated that the failure of catalytic decomposition of methylene blue originated from the formation of soluble CdSO4 by oxidizing S2 of as-prepared CdS. High resolu- tion transmission electron microscopy （HRTEM） further identified the active sites in the V-shaped regions ofCdS nanoparticles, confirmed by the simulated electric field distribution. To rationally coat oxides on CdS, the right candidates and their thicknesses have been considered by our tunneling model with trans- fer matrix method based on quantum mechanism, upon which the thickness of protective layer should be less than 0.5 nm to maintain a high tunneling probability, and thus one cycle of ALD TiO2 or AbO3 was proposed to passivate the CdS powder to balance the carrier transportation and corrosion suppres- sion. Based on HRTEM results, we found that the active V-shaped region was covered by ALD oxides （TiO2 or AbO3）. For each case, no soluble CdSO4 has been found before and after photocatalytic reactions based XPS measurements. Importantly, we noticed that with the passivation of one cycle of ALD, the catalyst＇s lifetime was elongated up to 〉14 times higher than that of the as-prepared CdS.

关键词： Cadmium sulfide PhotocatalysisPhoto-corrosion suppression Atomic layer deposition Quantum tunneling Transfer matrix method

Real time imaging of two-dimensional iron oxide spherulite nanostructure formation

在线全文

学校读者我要写书评

暂无评论

Nano Research 2019年第11期12卷 2889-2893页

作者： Wenjing Zheng Matthew R.Hauwiller Wen-I Liang Colin Ophus Peter Ercius Emory M.Chan Ying-Hao Chu Mark Asta xiwen du A.Paul Alivisatos Haimei Zheng Institute of New-Energy Materials School of Materials Science and EngineeringTianjin UniversityTianjin300350China Materials Sciences Division Lawrence Berkeley National LaboratoryBerkeleyCA94720USA Department of Chemistry University of CaliforniaBerkeleyBerkeleyCA94720USA Department of Materials Science and Engineering “National Chiao Tung University”Hsinchu30010TaiwanChina The Molecular Foundry Lawrence Berkeley National LaboratoryBerkeleyCA94720USA Department of Materials Science and Engineering University of CaliforniaBerkeleyBerkeleyCA94720USA Kavli Energy NanoScience Institute University of California-Berkeley and Lawrence Berkeley National LaboratoryBerkeleyCA94720USA

The formation of complex hierarchical nanostructures has attracted a lot of attention from both the fundamental science and potential applications point of *** structures with radial fibrillar branches have been found in various solids;however,their growth mechanisms remain poorly ***,we report real time imaging of the formation of two-dimensional(2D)iron oxide spherulite nanostructures in a liquid cell using transmission electron microscopy(TEM).By tracking the growth trajectories,we show the characteristics of the reaction front and growth *** observations reveal that the tip of a growing branch splits as the width exceeds certain sizes(5.5–8.5 nm).The radius of a spherulite nanostructure increases linearly with time at the early stage,transitioning to nonlinear growth at the later ***,a thin layer of solid is accumulated at the tip and nanoparticles from secondary nucleation also appear at the growing front which later develop into fibrillar *** spherulite nanostructure is polycrystalline with the co-existence of ferrihydrite and Fe3O4 through-out the growth.A growth model is further established,which provides rational explanations on the linear growth at the early stage and the nonlinearity at the later stage of growth.

关键词： liquid cell transmission electron microscopy(TEM) in situ TEM iron oxide spherulite nanostructures

Phase Transformations of Graphite and Carbon Black by Laser with Low Power Density

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Transactions of Tianjin University 2007年第5期13卷 318-321页

作者：孙景翟琪雷贻文杨星杜希文 School of Material Science and Engineering Tianjin University

The structure phase transformations of graphite and carbon black induced by pulsed laser were studied in this *** irradiation with laser beam of 1.06 μm wavelength and power density of 106 W·cm-2,both graphite structure and carbon black structure were changed *** results of Raman analyses and Transmission Electron Microscopy(TEM)observations show that graphite transforms into nanodiamond about 5 nm and carbon black is *** is demonstrated that graphite is the intermediate phase in the transformation from carbon black to diamond,and graphite is easier to transform into diamond by laser irradiation than carbon black.

关键词： pulsed laser graphite carbon black diamond

湿法喷丸处理YG8合金表面残余应力分析及对性能的影响

在线全文

学校读者我要写书评

暂无评论

粉末冶金技术 2007年第1期25卷 13-16页

作者：杜海燕杨晶孙景赵克远杜希文天津大学分析测试中心天津大学材料科学与工程学院天津现代职业技术学校

采用湿法喷丸工艺对YG8硬质合金进行表面处理,旨在提高材料的性能。通过X射线衍射法对不同喷射条件处理的合金表面残余应力及其深度分布进行了分析,并研究了残余应力对力学性能的影响。研究表明,湿法喷丸处理在硬质合金表层内产生残余... 详细信息

采用湿法喷丸工艺对YG8硬质合金进行表面处理,旨在提高材料的性能。通过X射线衍射法对不同喷射条件处理的合金表面残余应力及其深度分布进行了分析,并研究了残余应力对力学性能的影响。研究表明,湿法喷丸处理在硬质合金表层内产生残余压应力,喷射压力和喷射时间对残余应力及分布有显著影响,该应力及分布有利于材料性能的提高。应用该处理方法,在喷射压力为0.5MPa、喷射时间为2min的条件下,硬质合金的抗弯强度提高约11%,洛氏硬度为89.64HRA,磨损量减少36%。

关键词：硬质合金表面处理喷丸残余应力应力分布

在线全文

学校读者我要写书评

暂无评论

用激光法合成纳米金刚石

材料研究学报 2006年第1期20卷 33-36页

作者：孙景雷贻文杜希文翟琪杨星天津大学材料学院天津300072

使脉冲激光与石墨粉在空气中相互作用,并对其氧化提纯．对产物进行的显微激光拉曼光谱(Raman)与高分辨电子显微镜(HRTEM)分析表明,产物中含大量纳米金刚石颗粒,其尺寸为5 nm左右,且具有较多的晶体缺陷和残余内应力．提出了石墨转变为金... 详细信息

使脉冲激光与石墨粉在空气中相互作用,并对其氧化提纯．对产物进行的显微激光拉曼光谱(Raman)与高分辨电子显微镜(HRTEM)分析表明,产物中含大量纳米金刚石颗粒,其尺寸为5 nm左右,且具有较多的晶体缺陷和残余内应力．提出了石墨转变为金刚石纳米晶的机理:在脉冲激光产生的高温高压的条件下,具有石墨结构的原子团发生快速滑移切变,形成立方金刚石晶核,碳等离子体中高化学活性的碳粒子集团使金刚石晶核迅速长大,形成金刚石微晶．

关键词：材料合成与加工工艺石墨脉冲激光金刚石

在线全文

学校读者我要写书评

暂无评论

激光诱导固态转变合成金刚石研究进展

金刚石与磨料磨具工程 2005年第2期25卷 7-9页

作者：孙景杨星雷贻文翟琪杨晶杜希文天津大学材料科学与工程学院天津300072

本文介绍了激光诱导固态转变合成金刚石的研究进展,讨论了金刚石各种合成方法的机理,并提出一种激光诱导液体介质中石墨颗粒固态转变合成金刚石的新方法。研究的目的是改变现有激光轰击石墨合成纳米金刚石产出率过低的状况。方法是把石... 详细信息

本文介绍了激光诱导固态转变合成金刚石的研究进展,讨论了金刚石各种合成方法的机理,并提出一种激光诱导液体介质中石墨颗粒固态转变合成金刚石的新方法。研究的目的是改变现有激光轰击石墨合成纳米金刚石产出率过低的状况。方法是把石墨微粉放入水中,将其进行分散后导入一个循环系统,采用Nd-YAG脉冲激光(最大功率密度106W cm-2)轰击与其同轴循环流动的石墨颗粒悬浮液。收集反应产物并提纯,高分辨透射电子显微镜(HREM)分析表明产物为立方结构的金刚石,其颗粒尺寸为5nm。该方法产率比以往激光合成方法有了较大提高。

关键词：金刚石激光固态转变

在线全文

学校读者我要写书评

暂无评论

激光照射石墨悬浮液制备纳米金刚石的研究

金刚石与磨料磨具工程 2006年第5期26卷 24-27页

作者：孙景翟琪江雷雷贻文杨星杜希文天津大学材料学院天津300072

本文研究了一种用激光合成纳光金刚石的新方法。利用Nd:YAG脉冲激光照射循环流动的石墨悬浮液成功制备了纳米金刚石。与以往激光合成纳米金刚石方法相比,具有激光功率密度低(106W/cm2)、效率高的特点。利用高分辨透射电子显微镜(HRTEM)... 详细信息

本文研究了一种用激光合成纳光金刚石的新方法。利用Nd:YAG脉冲激光照射循环流动的石墨悬浮液成功制备了纳米金刚石。与以往激光合成纳米金刚石方法相比,具有激光功率密度低(106W/cm2)、效率高的特点。利用高分辨透射电子显微镜(HRTEM)分析了分别以炭黑、石墨为原料的不同实验产物的微观组织结构,在此基础上讨论了此方法的反应机理。研究结果表明:该方法制备的金刚石为立方结构,晶粒尺寸约为5nm,其相变路径为:由菱方石墨向立方金刚石的直接转变或六方石墨过渡到菱方石墨并最终形成立方金刚石的间接转变。

关键词：脉冲激光石墨金刚石纳米晶