JEJU Repository
General Graduate School
Faculty of Applied Energy System
Energy and Chemical Engineering
Dielectric barrier discharge plasma-mediated preparation of metal oxide nanostructures for catalytic and biological applications
- Abstract
- One-dimensional nanostructured materials have attracted a great deal of interest owing to their
potential applications in various industries. Due to the limitations and cost associated with
conventional low-pressure plasma systems, atmospheric pressure plasma techniques such as
dielectric barrier discharge (DBD) were investigated as an alternative approach for inducing
specific chemical reactions. Ruthenium dioxide (RuO2) and copper oxide (CuO) nanostructured
materials are widely used in supercapacitor electrodes, field emission devices and for catalytic
and biological applications. In such applications, size and shape dependent properties of
nanomaterials play critical roles in improving the performance. In this research, an attempt was
made to prepare one-dimensional RuO2 and CuO nanomaterials using DBD plasma. It was noted
that the morphology of nanomaterials prepared by exposing the precursor to the DBD plasma
was found to depend strongly on the characteristics of the substrate, physical properties of the
synthesis materials as well as on the composition of the feed gas. The morphologies obtained
from the plasma technique were also achieved by the conventional wet chemical methods using
polyethylene glycol surfactant. The plasma techniques necessarily avoided the use of surfactant
molecules, controlled the product morphology by few experimental variables, and showed the
feasibility for scale up. In addition, oxidation state of the materials could be controlled by
carefully selecting the plasma feed gas. The spherical and sheet shaped nanomaterials prepared
using the above techniques was analyzed for their shape dependent performances in industrially
and medically valuable applications such as photocatalysis, carbon monoxide (CO) oxidation and
antimicrobial activities. The photocatalytic behavior of spherical and sheet shaped RuO2 against
methylene blue dye showed an excellent shape dependent catalytic activity in the presence of
visible light. The CO oxidation using sheet-like RuOx/γ-Al2O3 showed the complete conversion
at 175 °C whereas it was achieved only at 200°C using spherical type RuOx/γ-Al2O3 and at every
experimental temperature, sheet shaped nanomaterials showed increased CO conversion
efficiency. Similar shape dependency was also noted when using grain-like and needle like
CuO/γ-Al2O3 at 300 °C. In the above catalytic cases, enhancement in the activity observed to
sheet-like nanomaterials was the cumulative effects of increase in the porosity, morphology,
catalyst stabilization and dispersion, and changes in the oxidation states. The RuO2 and CuO
nanomaterials were assessed for the shape dependent anti-microbial activities against Gram
positive and Gram negative bacteria. In all the cases, sheet like nanomaterials showed more
inhibitive effect than spherical or other types. Interaction of nanomaterials with bacteria created
an oxidative stress and released the corresponding metal ions and thus the microorganism lost its
essential nutrients for survival.
- Issued Date
- 2014
- Awarded Date
- 2015. 2
- Type
- Dissertation
- Department
- 대학원 에너지응용시스템학부 에너지화학공학전공
- Table Of Contents
- CHAPTER I INTRODUCTION
1.1 Ruthenium oxide and copper oxide nanostructured materials 1
1.2 Principles of dielectric barrier discharge (DBD) plasma 2
1.3 DBD Plasmas for nanomaterial synthesis 5
1.4 Shape dependent performance of RuO2 and CuO NMs in catalysis and biology 7
1.4.1 Photocatalytic activity 7
1.4.2 CO oxidation catalysis using RuOx/γ-Al2O3 and CuO/γ-Al2O3 8
1.4.3 Antibacterial activity of RuO2 and CuO NMs 9
1.5 Focus of current research 11
References 12
CHAPTER II EXPERIMENTAL METHODS
2.1 Introduction 23
2.2 Materials used 23
2.3 DBD plasma reactor setup 23
2.4 Synthesis of RuO2 nanomaterials under DBD plasma 24
2.5 Plasma Synthesis of RuO2 using different substrates 25
2.6 Synthesis of RuO2 by conventional methods 26
2.7 Shape dependent photocatalytic activity of RuO2 26
2.8 Shape dependent antibacterial activity of RuO2 27
2.8.1 Thiobarbituric acid reactive species (TBARS) assay 28
2.9 Shape dependent CO oxidation using RuOx /γ-Al2O3 28
2.9.1 Syntheses of catalysts 28
2.9.2 Experimental part 29
2.10 Plasma synthesis of CuO nanomaterials 30
2.11 Synthesis of CuO by conventional methods 30
2.11.1 Antibacterial activity of CuO nanomaterials 31
2.11.2 Metal ion release analysis 33
2.12 Shape dependent CO oxidation performance using CuO /γ-Al2O3 33
References 34
CHAPTER III RESULTS AND DISCUSSIONS
3.1 Influence of plasma on the morphology of RuO2 35
3.1.1 Absorbance measurement by UV-visible spectrometer 36
3.1.2 X-ray diffraction study for structural analysis 36
3.1.3 X-ray photoelectron study for surface analysis 37
3.1.4 Surface morphological analysis 39
3.1.5 Morphological confirmation studies by FESEM 41
3.1.5.1 Morphologies obtained in the absence of plasma 41
3.1.5.2 Investigation on the effects of plasma treatments 42
3.1.6 Evolution of temperature during plasma reaction and its influence on the morphology 43
3.1.7 Possible chemical reaction mechanism mediated by plasma species 45
3.2 Effect of substrates on the plasma synthesis of RuO2 48
3.2.1 Structure and composition analysis 48
3.2.2 Morphological studies 49
3.2.2.1 Preparation of RuO2 NMs using different substrates under Ar plasma 49
3.2.2.2 Preparation of RuO2 NMs using different substrates under Ar + O2 plasma 51
3.2.3 Particle size analysis and zeta potential 53
3.2.4 Photocatalytic properties 56
3.3 Alternative way of tailoring the morphology of RuO2 62
3.3.1 X-ray diffraction study for structural analysis 62
3.3.2 Surface morphological analysis. 63
3.3.2.1 Effect of concentration of NaOH and PEG on the
morphological structure of RuO2 nanomaterials 64
3.3.3 Analysis of functional groups using FT-IR spectroscopy 65
3.3.4 XPS surface chemical analysis 66
3.3.5 Stability of RuO2 nanomaterials 68
3.3.6 Shape dependent anti-bacterial effects of RuO2 nanomaterials 68
3.4 Shape dependent CO oxidation performance of RuOx/γ-Al2O3 74
3.4.1 Characterization of the catalyst 74
3.4.2 CO oxidation performance of the catalysts 80
3.4.3 Discussions 83
3.5 The DBD Plasma-mediated synthesis of CuO nanomaterials 87
3.6 Shape dependent antibacterial performance of CuO NMs 90
3.6.1 X-ray diffraction study for structural analysis 90
3.6.2 Surface morphological analysis 91
3.6.3 Particle size analysis and surface charge measurement 95
3.6.4 Functional group and surface chemical analysis 96
3.6.5 Results of antibacterial activity98
3.7 Shape dependent CO oxidation performance of CuO nanomaterials 105
3.8 Summary and Future directions 108
References 110
CHAPTER IV APPENDICES
4.1 List of abbreviations used 123
4.2 Calculations used 124
4.3 List of publications in international journals 127
4.4 Patent/s 128
4.5 Contribution to international conferences 129
4.6 Memories 130
4.7 About the author 131
- Degree
- Doctor
- Publisher
- 제주대학교 대학원
- Citation
- Antony Ananth. (2014). Dielectric barrier discharge plasma-mediated preparation of metal oxide nanostructures for catalytic and biological applications
- Appears in Collections:
- Faculty of Applied Energy System > Energy and Chemical Engineering
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