兰州大学机构库 >物理科学与技术学院
锰氧化物纳米材料的制备及生长机理研究
Alternative Titlepreparation and growth mechanism of manganese oxides nanomaterials
闫德
Thesis Advisor闫鹏勋
2009-05-30
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name博士
Keyword锰氧化物 纳米材料 水热 生长机制 微波吸收
Abstract随着现代社会的飞速发展,能源与环境问题越来越突出。纳米科技的飞速发展为解决能源与环境危机提供了无尽的机遇与广阔的前景。锰氧化物的优异性质使得它在催化、吸附、离子交换、通讯、微波铁氧体、软磁铁氧体、气敏、湿敏等诸多领域都有广泛的应用。本文主要关注的是它在能源和环境领域的应用:以锰的氧化物作为锂离子二次电池的正极材料不仅具有造价低廉、能量密度高、安全性高等优点,而且对环境不会产生任何污染;锰氧化物作为微波吸收材料能消除或屏蔽电子设备所造成的电磁污染,净化人类的生存环境。本论文以倡导绿色环保为时代背景、以纳米科技的飞速发展为科学背景、以锰氧化物在二次电池和微波吸收领域的应用为着眼点,着重研究了各种不同形貌锰氧化物低维纳米材料的制备、生长机制及形貌控制,并初步研究了锰氧化物纳米材料的微波吸收特性,为进一步深入研究奠定基础。 本论文的主要研究内容、研究成果及创新点如下: 1、 无需任何模板和表面活性剂的辅助,只用KMnO4<下标!>和H2<下标!>O为反应物,用水热法制备了分级结构的花状自组装MnO2<下标!>多孔微球和γ-MnOOH纳米带。我们对其微观形貌和结构进行了表征,首次提出了一个包含两个竞争因素,即温度和库仑相互作用的竞争机制,对其生长机理进行了很好的解释。根据我们所提出的生长机制,推论出了得到均一形貌及两种形貌在产物中所占比例的控制方法,并在实验中得到了验证,实现了产物形貌较为精确的控制。 2、 无需任何模板和表面活性剂的辅助,只用KMnO4<下标!>和H2<下标!>O为反应物,用水热法在硅基底上制备了锰氧化物多层膜。所制得的多层膜由一层单晶纳米片所组成的表面多孔层和一层或多层数目不等的底部非晶层组成。我们对其微观结构进行了深入表征,结果表明,表面多孔层是钠水锰矿结构的MnO2<下标!>,非晶底层中可能包含有γ-MnOOH、γ-Mn3<下标!>O4<下标!>、γ-MnO2<下标!>、α-MnO2<下标!>,在底层和基底的界面上可能存在SiO2<下标!>和结合了–OH的Mn离子和Si离子。为探索其生长机制,我们首次提出了一个包含内应力的产生、积累、释放和化学反应同时存在的复杂机制,成功的解释了这种多层膜的生长机制。 3、 用水热法结合后续热处理制备了黑水锰矿(β-MnOOH 和γ-Mn3<下标!>O4<下标!>)和Mn3<下标!>O4<下标!>纳米颗粒及Mn2<下标!>O3<下标!>三维网状结构。研究了三维网状结构的形成过程。对产物的微波吸收性质进行了测试,着重研究了颗粒大小,热处理温度,热处理时间对它们微波吸收性能的影响,并跟相应的块体材料进行了对比。详细分析了产物微波吸收的机理,为锰氧化物在微波吸收领域的实际应用打下基础。
Other AbstractWith the rapid development of modern society, energy and environment problem have aroused more and more attention, however, new approaches and chances to solve these problems are provided by the fast development of nanoscience and nanotechnology. Manganese oxides with excellent properties have wide applications in various fields, for example, catalysts, absorbers, ion exchange, communication, microwave ferrite, soft magnetic ferrite, gas sensor, humidity sensors and many other fields. Here, our attention is focused on its applications in the following two fields, energy and environmental protection. It does not only has the advantages of low prices, high energy density and high safety, but also has no harm to the environment as the cathode material of lithium-ion secondary batteries. It can also eliminate the electron magnetic pollution caused by various kinds of electronic devices as an microwave absorber, thus purifies the human living environment. Therefore, with the call for environmental protection as the times background, the rapid development of nanoscience and technology as the scientific background and the respect of its applications in the fields of lithium-ion secondary batteries and microwave absorption, the preparation, growth mechanism and morphology control of the low dimensional manganese oxides nanomaterials were investigated. Moreover, its application as microwave absorber was primarily studied which lays a solid foundation for further investigations. The content, results and originalities of this research are as follows: 1. 3D self-assembled flowerlike hierarchical spheres of MnO2<下标!> and γ-MnOOH nanobelts were prepared by a simple hydrothermal method, using KMnO4<下标!> and H2<下标!>O as reactants, without any templates and surfactants. Morphology and structure of the product were characterized. A growth mechanism was proposed for the first time, which involved two competitive factors, temperature and Coulomb interaction, to understand the formation mechanism of the product. A simple morphology control method to obtain products of uniform morphology and their proportion in the product, which deduced from the proposed mechanism was supported by parallel experiments, thus the morphology of the product can be controlled. 2. Manganese oxde film on Si substrate was obtained by hydrothermal method, using KMnO4<下标!> and H2<下标!>O as reactants, without the assistance of any templates and surfactant...
URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/229567
Collection物理科学与技术学院
Recommended Citation
GB/T 7714
闫德. 锰氧化物纳米材料的制备及生长机理研究[D]. 兰州. 兰州大学,2009.
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