oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 56 )

2018 ( 1025 )

2017 ( 1075 )

2016 ( 1032 )

Custom range...

Search Results: 1 - 10 of 41097 matches for " 魏子栋 "
All listed articles are free for downloading (OA Articles)
Page 1 /41097
Display every page Item
磷化过程的Taguchi设计
魏子栋
电化学 , 1996,
Abstract: 通过对磷化液配方及磷化工艺的改进，解决了磷化液沉淀多，不稳定及磷化膜微观结构差的问题．针对钢铁磷化过程中出现的磷化膜质量与磷化面积之间的非线性关系，应用Ｔａｇｕｃｈｉ方法，对磷化过程进行了优化，实现了磷化膜质量与磷化件面积之间的线性关系，磷化液连续循环使用的性能也得到根本的改进
“中庸”与“催化”随想
Rambling between “Zhong Yong” and “Catalysis”
魏子栋
- , 2016, DOI: 10.13208/j.electrochem.151144
Abstract: 摘要 “中庸”是传统的中国智慧，由孔子提出，不断被他的追随者丰富. “中庸”追求在各种矛盾中寻求平衡，并认为“过分”和“不及”都是不好的. 对于一个成功的催化剂，反应物的吸附，既不能太强，也不能太弱. 在这一点上，“催化”与“中庸”有极为相似之处. 本文以孔子与他的学生对话开始，先讲了3个 著名的“中庸”老故事，结合3个有“中庸”味道的“催化”案例，最后得出：好的“催化”，即是具有“中庸”味道的“催化”.
“Zhong Yong” represents a traditional Chinese wisdom, which was first proposed by Confucius and continuously richened by his followers. “Zhong Yong” pursues the balances among all kinds of contradictions, and insists that neither “too much” nor “not enough” is good. For a successful catalyst, on which the adsorption of reactants must be not so strong and not so weak either. On this point of view, there are the same pursuits for “Zhong Yong” and catalysis. In this paper, the author starts his story with a conversation between Confucius and his student, followed by 3 interesting stories happening in the ancient China, and then 3 examples in catalysis. In comparison with these stories and examples we can conclude that “Zhong Yong” and catalysis do share some common aesthetic standard. Doing catalysis with a taste of “Zhong Yong” must be very interesting and wonderful
《燃料电池电化学催化与催化剂》专辑序言 ——新能源产业的关键技术：燃料电池
Special issue: Electrocatalyst and Electrocatalysis in Fuel Cells Preface
魏子栋
- , 2016, DOI: 10.13208/j.electrochem.151140
Abstract: 摘要 随着世界石油储量的快速消耗以及由此带来的环境污染问题，世界各国都在积极寻找清洁无污染的可再生替代能源。以氢气的生产、储存、运输及利用为基础的“氢能经济”，对于摆脱人类对化石能源的依赖，实现可持续发展具有重要的意义。燃料电池作为将氢能直接转化为电能的洁净发电装置，是替代现有燃油发动机的最佳选择，不仅可以为现代交通工具提供理想的动力源，而且在移动通讯、潜艇、航空飞行器等方面也具有广阔的应用前景。
In the last two decades, fuel cells captured worldwide attention as a promising renewable emission-free technology to meet the increasing demand of clean energy for stationary and transportation applications. Currently, platinum (Pt) is the most widely used electrocatalyst for both hydrogen oxidation reaction (HOR) at anode and oxygen reduction reaction (ORR) at cathode. However, the high-cost and scarcity of Pt have become the major challenges for commercialization of fuel cells. To overcome the above mentioned problems, great progress has been made in developing more active electrocatalysts on the basis of Pt-based and Pt-free electro catalysts. For the Pt-based electrocatalysts, composition, morphology, surfaces tructure, synthesis method, and post-treatment play significant roles in determining their activity and stability. In general, theactivity of Pt-based electrocatalysts can be enhanced by alloying Pt with other transition metals, forming a core-shell structure to improve the utilization of Pt atoms, forming and maintaining structures with only the highest active facets exposed to electrolytes, and creating a porous structure toincrease the surface area and strain. For the Pt-free electrocatalysts, a great progress has been made in the last decade, including heteroatom-containing carbon, transition metal oxides and transition metal macrocyclic compounds. The best performing non-precious catalysts even exceed those Pt-based catalysts in alkaline electrolytes. Generally, their ORR activity is less competitive in acidic media. To review the achievements that have been madein China and push forward the further development of electrocatalyst and electrocatalysis in fuel cells, some leading scientists were invited to contribute their recent advances and prospects in this field. I wish to take this opportunity to thank all the authors, reviewers, and editorial staffs of Journal of Electrochemistry for their professional contributions to this special issue
电化学催化的密度泛函研究
李莉,魏子栋
电化学 , 2014, DOI: 10.13208/j.electrochem.130893
Abstract: 围绕电化学催化问题，综述了密度泛函理论研究电极电势、电催化剂结构与物种的吸附脱附、电子转移以及电催化剂活性、稳定性的关系.电极电势与金属催化剂d带中心影响着电极表面物种的形成、吸附和脱附，通过催化剂合金化或表面修饰、载体-催化剂相互作用可实现催化剂d带中心的调控，寻找最优吸附强度的催化剂，以期提高催化活性；通过电极电势与催化剂的HOMO能级的调控，实现与电子受体物质LUMO能级的匹配，达到促进或抑制催化剂与电子受体物质之间电子转移的快慢.
非贵金属氧还原催化剂的研究进展
Recent Progress in Non-Precious Metal Catalysts for Oxygen Reduction Reaction
王俊,魏子栋()
- , 2017, DOI: 10.3866/PKU.WHXB201702092
Abstract: 开发可替代铂的非贵金属催化剂是今后燃料电池催化剂的重要发展方向，本文结合课题组研究的工作，总结了近年来非贵金属在氧还原催化方面的研究进展。并着重从材料合成和机理两个方面分析了目前在开发过渡金属氧化物、含过渡金属的氮掺杂碳材料和杂原子掺碳材料中存在的问题，提出了这些非金属催化剂今后的研究重点和努力方向。Email: zdwei@cqu.edu.cn; Tel: +86-23-65105161
Non-precious metal catalysts should be studied to substitute precious Pt catalysts. Recent developments of non-precious-metal catalysts (combined with the achievements of our group) are summarized in this paper. The main issues that exist in the transition metal oxides, metal-nitrogen-carbon material, and heteroatom-doped carbon material are highlighted from the aspects of the synthetic methods and mechanisms. The research tendency and perspective of these non-precious metal catalysts are provided
质子交换膜燃料电池非铂电催化剂研究进展
聂瑶,丁炜,魏子栋
化工学报 , 2015, DOI: 10.11949/j.issn.0438-1157.20150785
Abstract: 质子交换膜燃料电池(PEMFCs)目前主要催化剂为贵金属Pt基催化剂。然而,Pt价格高、储量低等问题严重阻碍了PEMFCs的商业化进程。发展低成本、高性能的氧还原催化剂是解决铂资源短缺、降低燃料电池成本、实现燃料电池商业化的关键。结合本课题组的研究工作,综述了最近几年非铂催化剂在燃料电池阴极氧还原方面的研究进展,着重探讨了新型氮掺杂碳基纳米材料的设计与制备,并概述了非铂催化剂面临的困难以及未来发展方向。
泡沫镍载碳化钨催化剂上的析氢反应
吴梅,魏子栋,沈培康
催化学报 , 2007,
Abstract: ？结合直接化学还原法和交替微波法制备了泡沫Ni载Ni-WC催化剂,用X射线衍射、扫描电镜和透射电镜对催化剂进行了表征,研究了其析氢电催化性能.结果表明,在相同条件下,泡沫Ni载Ni-WC催化剂的析氢起始电位与泡沫Ni相比降低了60mV左右.电解质浓度和温度对泡沫Ni载Ni-WC催化剂的析氢电催化活性有很大影响.
动态库仑法测定水果、疏菜、药物中微量抗坏血酸
魏子栋,郭培植,田家乐
分析化学 , 1990,
Abstract: 本文提出一种新的测定抗坏血酸的方法——动态库仑法。该方法与测定抗坏血酸的标准方法,对大量样品的对照试验表明其结果相合。此外本文就测定过程中有关的问题做了较为深入的探讨。
不同氮掺杂石墨烯氧还原反应活性的密度泛函理论研究
Density Functional Theory Study of Oxygen Reduction Reaction on Different Types of N-Doped Graphene
王俊,李莉(),魏子栋()
- , 2016, DOI: 10.3866/PKU.WHXB201512091
Abstract: N掺杂石墨烯作为一种具有较高活性和稳定性的氧还原反应(ORR)催化剂，受到人们的广泛关注。然而不同的N掺杂类型对氧还原活性的影响一直存在争议。本文通过密度泛函理论分别对石墨型和吡啶型两种N掺杂石墨烯的ORR活性进行比较研究。能带结构分析表明，石墨氮掺杂石墨烯(GNG)的导电性随掺N量的增加而降低；吡啶氮掺杂石墨烯(PNG)的导电性则随掺N量的增加先提高后降低。当N掺杂浓度达到4.2%(原子分数)时，PNG具有最优导电性。且当N掺杂浓度大于1.4%时，PNG的导电率总是高于GNG。氧还原自由能阶梯曲线发现O2的质子化是整个氧还原过程的潜在控制步骤。在同等氮掺杂浓度下，O2的质子化自由能能变在GNG上低于在PNG上，意味着若在同等电子传输能力的情况下，GNG具有比PNG更优异的催化活性。进一步分析发现：当N掺杂浓度在低于2.8%时，GNG和PNG导电性差异小，其催化ORR活性由O2质子化反应难易程度决定，GNG的催化活性优于PNG；当N掺杂浓度高于2.8%时，氮掺杂石墨烯的电子传输性能(导电性)成为决定催化剂ORR活性的主要因素，因此PNG表现出较GNG更高的活性。
N-doped graphene has aroused much interest owing to its high activity and stability in oxygen reduction reaction (ORR) catalysis. However, the contribution of different types of N-doped graphene to ORR activity remains in dispute. Based on this issue, this paper conducts a comparative study of the ORR on graphitic N-doped graphene (GNG) and pyridinic N-doped grapheme (PNG). Band structure calculations show that the conductivity of GNG decreases as the nitrogen content increases; while that of PNG first increases to the highest at nitrogen content of 4.2% (atomic fraction), and then decreases. The conductivity of PNG is always higher than GNG when the doped nitrogen content is greater than 1.4%. Additionally, the free energy diagram of ORR shows that protonation of O2 is the potential-determining step among the whole ORR process, and the free energy change of this step on GNG is lower than on PNG, suggesting that GNG has higher ORR activity than PNG if their electron transport ability are the same. When the N content is lower than 2.8%, the conductivity difference between GNG and PNG is almost negligible, thus GNG with a higher capacity of O2 protonation exhibits better ORR activity than PNG. When the N content is greater than 2.8%, in this case, conductivity rather than free energy change will dominate, therefore the ORR on PNG will occur faster than on GNG because of its higher conductivity
氧在Pt-Fe-Co/C合金催化剂上的还原
魏子栋,郭鹤桐,唐致远
催化学报 , 1995,
Abstract: ？
Page 1 /41097
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.