半導(dǎo)體的光催化特性作為一種重要的材料性能,在有機物污染降解、細菌滅活、水分解和二氧化碳還原等方面具有重要的應(yīng)用價值。利用半導(dǎo)體光催化可以環(huán)保地將光能轉(zhuǎn)化為化學(xué)能,為解決能源短缺問題提供了一種可行的解決方案,因此這方面的研究發(fā)展非常迅速。金屬氧化物、氮基或硫基半導(dǎo)體、硅、III-V族半導(dǎo)體、導(dǎo)電聚合物、石墨烯基材料、新興層狀化合物等都可用于光催化。本論文工作基于半導(dǎo)體催化基本原理以及金屬氧化物和異質(zhì)結(jié)構(gòu)中載流子特性,研究納米結(jié)構(gòu)ZnO和TiO₂的基本缺陷,并通過將這些納米材料與微波合成的石墨烯氧化物進行雜化來調(diào)控這些缺陷,最終改善納米材料在污染物分解、氧化降解以及CO₂轉(zhuǎn)化催化性能。首先,制備了ZnO納米顆粒,并采用微波合成將ZnO納米顆粒與氧化石墨烯（GO）復(fù)合得到石墨烯含量分別為10%、20%和30%的納米ZnO-GO復(fù)合材料（GZCs）。獲得的復(fù)合材料中納米氧化鋅很好地分散在石墨烯層之間或者之上。退火溫度和GO含量對復(fù)合材料的紫外吸收光譜、光致發(fā)光、氧化鋅缺陷態(tài)、電子順磁共振譜、光電響應(yīng)和電荷轉(zhuǎn)移特性有重要的影響。GZC的高分辨透射電鏡圖... 

【文章來源】：華南理工大學(xué)廣東省 211工程院校 985工程院校 教育部直屬院校

【文章頁數(shù)】：148 頁

【學(xué)位級別】：博士

【文章目錄】：
摘要
Abstract
Chapter 1 Introduction and Literature review
    1.1 Background
    1.2 Introduction to materials and defect states
    1.3 Wide bandgap semiconductors
    1.4 ZnO and TiO_2
    1.5 Graphene and Graphene oxide
    1.6 Reduced graphene oxide and semiconductor composites
        1.6.1 Reduced graphene oxide-ZnO
        1.6.2 Reduced graphene oxide-TiO_2
    1.7 Defects in semiconductors
    1.8 ZnO defect states
    1.9 TiO_2 defect states
    1.10 Effect of defect states on photocatalysis
    1.11 Recovery of photocatalyst
    1.12 Chemical synthesis of catalyst magnetic nanocomposites
        1.12.1 Co-precipitation Method
        1.12.2 Microwave Synthesis
    1.13 The objective of this work
Chapter 2 Experimental and Instrumentation
    2.1 Introduction
    2.2 Experimental section
        2.2.1 Reagents and Chemicals
        2.2.2 Sample preparations
    2.3 Instrumentation
        2.3.1 X-ray diffraction (XRD)
        2.3.2 RAMAN spectroscopy
        2.3.3 Transmission electron microscopy (TEM)
        2.3.4 Scanning electron microscopy (SEM)
        2.3.5 UV-VIS spectroscopy
        2.3.6 X-ray photoelectron spectroscopy (XPS)
        2.3.7 PL spectroscopy
        2.3.8 Photocurrent and EIS
    2.4 Summary
Chapter 3 Lattice defects of ZnO and hybrids with GO: Characterization, EPR and Optoelectronic properties
    3.1 Introduction
    3.2 Preparation of samples
        3.2.1 Preparation of ZnO nanoparticles
        3.2.2 Preparation of GZ composites
    3.3 Microstructures, morphology and phase composition characterization
    3.4 Photoluminescence properties
    3.5 Bonding and defect characterization by XPS
    3.6 Absorbance properties
    3.7 Electrochemical properties
    3.8 Electron paramagnetic resonance properties
    3.9 Summary
Chapter 4 Defect engineering of ZnO nanoparticles by graphene oxide leading to enhanced visible light photocatalysis
    4.1 Introduction
    4.2 Preparation of samples
        4.2.1 Preparation of zinc oxide nanoparticles
        4.2.2 Preparation of Fe_3O_4@Si O2 magnetic nanoparticles
        4.2.3 Preparation of GZF composites
    4.3 Microstructures, morphology and phase composition characterization
    4.4 Magnetic measurements
    4.5 Photoluminescence properties
    4.6 Bonding and defects characterizations by XPS
    4.7 Absorbance properties
    4.8 Photocurrent response
    4.9 Photocatalytic activity
        4.9.1 Photocatalytic degradation of methylene blue and BPA
        4.9.2 Apparent rate constants
        4.9.3 Methylene blue and BPA photodegradation
    4.10 Summary
Chapter 5 ZnO flowers and graphene oxide hybridization for efficient photocatalytic degradation of o-xylene in water
    5.1 Introduction
    5.2 Sample preparation
        5.2.1 Preparation of zinc oxide flowers
        5.2.2 Preparation of GZ-hybrids
    5.3 Growth of ZnO from particles to flowers
    5.4 Microstructures, morphology and phase composition characterization
    5.5 Absorbance properties
    5.6 Photoluminescence properties
    5.7 ZnO-graphene oxide bonding and defect characterization by XPS
    5.8 Photocurrent response
    5.9 Electrochemical Properties
    5.10 Photocatalytic activity
        5.10.1 Photo-catalytic degradation of o-xylene
        5.10.2 Effect of Ethanol on the degradation percentage of o-xylene
        5.10.3 Effect of potassium iodide (KI) on the degradation percentage of o-xylene ..
        5.10.4 Effect of N2 gas purging on photo-catalytic degradation of o-xylene
        5.10.5 Recyclability
    5.11 Summary
Chapter 6 TiO_2 hollow nanobox-graphene composites for excellent photo-catalytic conversion of CO_2 to CH_4
    6.1 Introduction
    6.2 Preparation of samples
        6.2.1 Preparation of hollow TiO_2 nanoboxes
        6.2.2 Preparation of Fe_3O_4@SiO_2 magnetic nanoparticles
        6.2.3 Preparation of TFSG composites
    6.3 Microstructures, morphology and phase composition characterization
    6.4 Bonding and defect characteristics by XPS
    6.5 Electron paramagnetic resonance measurements
    6.6 Absorbance and magnetic properties
    6.7 Photo current and electrochemical measurements
    6.8 Photocatalytic activity
        6.8.1 Photocatalytic CO_2 conversion to CH_4 and H_2 production
        6.8.2 Photocatalytic CO_2 conversion to CH_4
        6.8.3 Photocatalytic H_2 evaluation
    6.9 Summary
Chapter 7 Conclusion and Future work
    7.1 Conclusions
    7.2 Future work
References
List of Publications
Acknowledgements



本文編號：3602636