ZnO (La,Sr)CoO3纳米复合材料制备及光催化性能

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II
氧化锌(ZnO)是一种宽带隙半导体无机材料,室温下的带隙宽度约为 3.37eV
激子结合能高达 60meV,被广泛用于紫外激光器、太阳能电池、发光二极管、
纳米发电机等领域。镧锶钴氧(La,Sr) CoO3LSCO)作为一种 ABO3型钙钛矿,
是一类具有独特物理性质和化学性质的无机功能材料,由于这类化合物具有稳定
的晶体结构、独特的电磁性能以及很高的氧化还原、氢解、异构化等活性,在环
境保护、工业催化和光催化等领域具有很大的开发潜力。
本文首先通过两步法Si 片基底上制备出一层具有择优取向生长特性的
ZnO 纳米棒阵列,然后在 ZnO 纳米棒基础上,通过水热法制备出一种均匀分布、
厚度为纳米级,面积呈平方微米级的纳米片。在众多的纳米材料的研究工作中,
这种特殊形貌的纳米片较为少见,具有一定的科研价值。本文还重点探讨了制备
条件(生长液种类、生长时间、生长温度)对纳米片形貌的影响,再以 ZnO
米棒和纳米片为基底,复合 LSCO 钙钛矿材料。同时,还对 ZnO 纳米棒、纳米
片以及复合材料在形貌、晶体结构、热分解性质、紫外可见吸收光谱、光催化性
质等方面进行详细的分析和研究。
本文的主要研究如下:
1、所制备的 ZnO 纳米棒在形貌上表现出均匀整齐的特点,单根纳米棒
直径约为 50nm,长度约为 800nm。并且纳米棒沿着竖直方向生长,具有[0001]
方向的择优取向特性。
2)、 在纳米片的生长条件研究中发现,生长液含硝酸铜条件下所制备的纳
米片形貌均匀、厚度约为纳米级、面积为平方微米级。通过 TEM 的研究表明,纳
米片的晶体结构为单晶结构。
3、在对 ZnO 纳米棒和 ZnO 纳米片的紫外可见吸收光谱研究过程中,得
ZnO 纳米片和 ZnO 纳米棒两者在紫外光的吸收带边缘都处在 380nm 左右,
紫外光波长范围内,纳米棒的吸收高于纳米片。
4)、 ZnO 纳米棒和纳米片为基底,然后复合 LSCO 钙钛矿材料,得到
ZnO/钙钛矿纳米复合材料。通过对 LSCO 的热重实验,得知在 550℃时 LSCO
化合物趋于稳定。利用 XRD 衍射图谱分析复合材料的晶体特性,复合材料的各
个衍射峰与相应的 ZnO 和钙钛矿衍射峰完全匹配,说明纳米 ZnO 与钙钛矿材料
较好的复合在一起。
5在光催化研究中发现,就单一材料体系而言,ZnO 纳米棒的催化性能
最高。并且,ZnO 纳米棒/LSCO 复合材料的催化效果优于单纯的 ZnO 纳米棒和
III
钙钛矿材料体系。
关键词:水热法、ZnO 纳米棒、ZnO 纳米片、(La, Sr) CoO3
光催化
IV
ABSTRACT
Zinc oxide(ZnO) as a kind of inorganic material, is a semiconductor material
with a direct band gap of 3.37eV, and has a high excition binging energy of 60meV,
widely used in ultraviolet lasers, solar battery, light emitting diode, nano generator, etc.
(La, Sr) CoO3 (LSCO)as a kind type of ABO3 perovskite compounds, is a kind of
unique physical characters and chemical properties of the inorganic functional
material, due to this kind of compounds has the stable crystal structure, unique
electromagnetic performance and high active in oxidation reduction, hydrogenolysis,
and isomerization, so it has a great development potential in environmental protection,
industrial catalytic and photocatalysis field, etc.
In this paper, ZnO nanorod array with orientation property was fabricated on the
Si substrate through two-step method, and then, the uniform arranged ZnO nanosheet
with thickness of the nano level (about 8 nm) and area of the square microns level
(about 40 m2) was prepared by hydrothermal method based in the ZnO nanorod
array. The special morphology of nanosheet is found rarely in much nanomaterial
research work, so that it has advisable scientific research value. This paper also
discussed the influence of preparation conditions (type of growth liquid, growth time,
growth temperature) on the morphology of nanosheet. Perovskite material LSCO was
composited with the basement of ZnO nanorod and ZnO nanosheet respectively.
Meanwhile, the morphology, crystal structure and thermal decomposition property,
UV-vis spectra and photocatalysis property of the ZnO nanorod, ZnO nanosheet and
composite materials were analyed and researched in detail.
The main research states as below:
The morphology feature of ZnO nanorods prepared was uniform and well
arranged. And each nanorod was shown that its diameter was about 50 nm and the
length was about 800nm. Meanwhile, nanorod grown in preferred orientation of the
vertical direction [0001].
From the research in growing conditions, the preferable and uniform arranged
ZnO nanosheet, whose thickness was the nanometer level and area was the square
microns level, would be fabricated in the growth liquid included copper nitrate. From
the picture of Transverse electric and magnetic field (TEM), it was known definitely
that ZnO nanosheet was the single crystal structure.
The UV-light absorption band of ZnO nanorod and ZnO nanosheet, in their
UV-vis spectra research, both were at 380nm. By way of addition, the absorption
V
property of ZnO nanorod was great higher than ZnO nanosheet in the UV wavelength
range, however, which is opposite in visible wavelength range.
LSCO nanomaterial was compounded with the basement prepared by ZnO
nanorod and ZnO nanosheet. Through the TGA research of LSCO, LSCO compound
was more stable in 550 . It was indicated that, in the XRD analysis, the prepared
composite material’s diffraction peak can both match with the standard card,
meanwhile, nano ZnO was composited well together with perovskite.
In the photocatalysis experiment, it is concerned that ZnO nanorod has the
greatest photocatalysis property in the single material system. Meanwhile the
composite of ZnO nanorod/LSCO has better photocatalysis effect than pure ZnO
nanorod and pure perovskite material.
Keywords: hydrothermal method, ZnO nanorod, ZnO
nanosheet, (La, Sr) CoO3, photocatalysis
VI
摘要
ABSTRACT
第一章 ................................................................................................................ 1
§1.1 纳米半导体材料 ............................................................................................. 1
§1.1.1 纳米材料 .............................................................................................. 1
§1.1.2 纳米半导体材料 .................................................................................. 2
§1.1.3 纳米半导体材料的特性 ...................................................................... 2
§1.2 ZnO/(La,Sr)CoO3 纳米复合光催化材料 ...................................................... 4
§1.2.1 ZnO 材料概述 ....................................................................................... 4
§1.2.2 钙钛矿(La, Sr)CoO3(LSCO)材料 ........................................................ 5
§1.2.3 ZnO/LSCO 纳米复合光催化材料 ........................................................ 6
§1.3 纳米复合催化剂的制备 ................................................................................ 7
§1.4 ZnO 纳米复合光催化剂国内外研究现状 ..................................................... 8
§1.5 课题的研究意义 .......................................................................................... 10
§1.6 课题研究的主要内容 .................................................................................. 10
第二章 ZnO 纳米结构的制备及表征 ....................................................................... 11
§2.1 引言 ............................................................................................................... 11
§2.2 纳米 ZnO 的主要制备方法 ......................................................................... 11
§2.3 主要实验试剂和仪器 ................................................................................... 13
§2.3.1 实验过程 ............................................................................................. 15
§2.3.2 样品的表征 ......................................................................................... 16
§2.4 实验结果与讨论 ........................................................................................... 16
§2.4.1ZnO 纳米棒的 SEM 图像和 XRD 图谱分析 ..................................... 16
§2.4.2 不同硝酸盐对纳米片的影响因素研究 ............................................ 18
§2.4.3 Cu2+对纳米片的影响因素研究 .......................................................... 20
§2.4.4 反应温度对纳米片的影响因素研究 ................................................ 21
§2.4.5 反应时间对纳米片的影响因素研究 ................................................ 24
§2.4.6 纳米片 AFM 研究 ............................................................................... 26
§2.4.7 纳米片 TEM 研究 ............................................................................... 26
§2.4.8 紫外可见(UV-vis)吸收光谱分析 ....................................................... 26
§2.5 本课题主要涉及的纳米 ZnO 制备原理 ...................................................... 27
§2.6 本章小结 ....................................................................................................... 29
第三章 ZnO/(La, Sr) CoO3纳米复合材料制备及表征 ............................................ 31
VII
§3.1 引言 .............................................................................................................. 31
§3.2 ABO3钙钛矿的主要性质 ............................................................................. 31
§3.2.1 晶体结构 ............................................................................................ 31
§3.2.2 电子结构 ............................................................................................ 32
§3.3 主要实验试剂和仪器 .................................................................................. 33
§3.4 实验制备过程 .............................................................................................. 34
§3.4.1 LSCO 的制备 ...................................................................................... 34
§3.4.2 纳米 ZnO/LSCO 复合材料的制备 .................................................... 34
§3.4.3 样品的表征 ........................................................................................ 34
§3.5 实验结果及分析 ........................................................................................... 34
§3.5.1 TGA 分析 ............................................................................................ 34
§3.5.2 XRD 图谱分析 .................................................................................... 35
§3.5.3 纳米 ZnO/LSCO 复合材料的 XRD 图谱分析 .................................. 36
§3.5.4 复合材料的 SEM 图像分析 ............................................................... 37
§3.6 本章小结 ....................................................................................................... 37
第四章 ZnO/(La, Sr) CoO3纳米复合材料光催化研究 ............................................ 38
§4.1 引言 .............................................................................................................. 38
§4.2 半导体光催化基本原理 .............................................................................. 38
§4.2.1 半导体光催化反应过程 ..................................................................... 38
§4.2.2 影响光催化活性的内在因素 ............................................................ 39
§4.2.3 影响光催化反应的外在因素 ............................................................ 40
§4.3 实验材料和器材 .......................................................................................... 41
§4.4 实验步骤 ...................................................................................................... 41
§4.4.1 光催化剂的制备 ................................................................................ 41
§4.4.2 仪器校准与标准甲基橙溶液制备 ..................................................... 41
§4.4.3 空白试验 ............................................................................................ 42
§4.4.4 光催化降解试验具体方案 ................................................................ 43
§4.5 ZnO 纳米棒、LSCOZnO 纳米棒/LSCO 复合材料的光催化特性研究 43
§4.6 ZnO 纳米片、LSCOZnO 纳米片/LSCO 复合材料的光催化特性研究 44
§4.7 本章小结 ...................................................................................................... 45
第五章 结论和展望 .................................................................................................... 47
§5.1 结论 .............................................................................................................. 47
§5.2 展望 .............................................................................................................. 48
参考文献 ...................................................................................................................... 49
ZnO (La,Sr)CoO3纳米复合材料制备及光催化性能.pdf

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作者:侯斌 分类:高等教育资料 价格:15积分 属性:58 页 大小:3.23MB 格式:PDF 时间:2025-01-09

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