This thesis reports the symthesis of five metal complexes, namely bis(piperidinylldithiocarbamato)nickel(II) (1), bis(tetrahydroquinolinyldithiocarbamato)nickel(II) (2), bis(N’-ethyl-N-piperazinyldithiocarbamato)nickel(II) (3), tris(morpholinodithiocarbamato)cobalt(III) (4) and tris(N’-ethyl-N-piperazinyldithiocarbamato)cobalt(III) (5).
These heterocyclic dithiocarbamate complexes have been characterised using common techniques such as Fourier Transform Infrared spectroscopy, elemental analysis and nuclear magnetic resonance spectroscopy. Nuclear magnetic resonance spectroscopy measurements were not conducted for complexes, due to their paramagnetic behaviour which adversely interferes with the technique. Single-crystal X-ray diffraction was used instead, which aided in the accurate elucidation of novel chemical structures of the complexes.
Three complexes were characterised using the technique; the chemical structures of the rest are already known in literature. Generally, dithiocarbamate complexes have been identified as compounds of technological importance, particularly as single-source molecular precursors for the fabrication of nanomaterials for widespread applications. However, interest has mainly been on alkyl derivatives. Thus, this thesis focuses on the use of heterocyclic dithiocarbamates complexes as single-source molecular precursors for the fabrication of the corresponding metal sulfide thin films and nanoparticles through thermal decomposition routes.
Thermal decomposition of the complexes (1)-(5) produced Ni-S, Co-S and Ni-Co-S nanoparticles and thin films which exhibited interesting morphological and optoelectronic properties. The above-mentioned systems were particularly chosen for their increased interest in magnetism, as well as energy generation and storage applications. In this thesis, the nature of the complexes and other reaction parameters were demonstrated to have an influence on the particle size, morphology, and phase purity of the nanoparticles and thin films produced. These properties have a profound impact on the efficiency of the nanoparticles and thin films, towards specific applications.
Table of Contents
CHAPTER ONE: INTRODUCTION AND LITERATURE REVIEW
1.1. General introduction
1.2. Literature Review
1.2.1. Nickel Sulfide (NixSy) Nanoparticles and Thin Films
1.2.2. Cobalt Sulfide (CoxSy) nanoparticles and thin films
1.2.3. Ternary Nanomaterials with Thiospinel Structure
1.2.4. Magnetic properties
1.2.5. Energy Applications
1.3. Statement of the research problem
1.4. Scope of the work
1.5. Aim and objectives of the work
1.6. Thesis layout
1.7. References
CHAPTER TWO : SYNTHESIS OF RARE PURE PHASE Ni3S4 AND Ni3S2 NANOPARTICLES IN DIFFERENT PRIMARY AMINE COORDINATING SOLVENTS
2.1 Introduction
2.2 Experimental details
2.2.1. Materials
2.2.2. Synthesis of ligands
2.2.3. Synthesis of complexes
2.2.4. Synthesis of NiS nanoparticles
2.2.5. Characterization techniques
2.3. Results and discussion
2.3.1. Characterization of the ligands and complexes
2.3.2. Single-crystal X-ray structures for complexes (1) and (3)
2.3.3. Nickel sulfide nanoparticles
2.4. Conclusion
2.5. References
CHAPTER THREE: HETEROCYCLIC DITHIOCARBAMATO-NICKEL(II) COMPLEXES SINGLE MOLECULAR PRECURSORS FOR NICKEL SULFIDE THIN FILMS
3.1. Introduction
3.2. Experimental details
3.2.1. Materials and methods
3.2.2. Synthesis of ligands and nickel complexes
3.2.3. Aerosol Assisted Chemical Vapour Deposition (AACVD) of nickel sulfide thin films
3.2.4. Characterization techniques
3.3. Results and discussion
3.3.1. Synthesis of single source precursors
3.3.2. Nickel sulfide thin films
3.3.3. SEM, EDX and Elemental Mapping analyses
3.3.4. Powder X-ray diffraction studies
3.3.5. Optical absorbance analysis
3.4. Conclusion
3.5. References
CHAPTER FOUR : FACILE SYNTHESIS OF BIFUNCTIONAL CoxSy NANOPLATES FOR EFFICIENT H2/O2 EVOLUTION AND SUPERCAPACITANCE
4.1. Introduction
4.2. Experimental details
4.2.1. Materials
4.2.2. Synthesis of ligand and cobalt complex
4.2.3. Synthesis of CoxSy nanoparticles
4.2.4. Characterization techniques
4.3. Results and discussion
4.3.1 Cobalt complex and thermogravimetric analyses
4.3.2 Single crystal X-ray crystallography structure for complex (4)
4.3.3. Phase Purity and morphology analyses
4.3.5. OER/HER electrocatalyst studies
4.3.6. Supercapacitor performances studies
4.4. Conclusion
4.5. References
CHAPTER FIVE: EFFECT OF CATIONIC DISORDER ON THE ENERGY GENERATION AND ENERGY STORAGE APPLICATIONS OF NixCO3-xS4 THIOSPINEL
5.1. Introduction
5.2. Experimental details
5.2.1. Materials
5.2.2. Synthesis of ligands and metal (Ni, Co) complexes
5.2.3. Preparation of NiCo2S4 nanosheets
5.2.4. Characterization techniques
5.3. Results and discussion
5.3.1. Synthesis of ligand and metal (Co, Ni) complexes and thermogravimetric analyses
5.3.2. Phase purity, christallinity and morphology analyses
5.3.3. XPS Measurements for the ternary samples (NiCoS-1 and NiCoS-2)
5.3.4. Electrocatalytic energy generation for the ternary samples (NiCoS-1 and NiCoS-2)
5.3.5. Electrochemical energy storage for the ternary samples (NiCoS-1 and NiCoS-2)
5.4. Conclusions
5.5. References
CHAPTER SIX: SUMMARY OF WORK AND FUTURE OUTLOOK
6.1. Summary and Conclusion
6.2. Future Work
Objectives and Topics
The primary objective of this thesis is to explore the use of heterocyclic dithiocarbamate metal complexes as single-source precursors for the controlled fabrication of nickel and cobalt sulfide nanomaterials. The research investigates how these precursors can be utilized to produce binary and ternary sulfides with specific particle sizes, morphologies, and phase purities to enhance their performance in magnetic, electrocatalytic (water splitting), and energy storage (supercapacitor) applications.
- Synthesis and characterization of heterocyclic dithiocarbamate complexes as single-source precursors.
- Fabrication and optimization of metal sulfide thin films and nanoparticles using thermal decomposition and AACVD methods.
- Investigation of reaction parameters (temperature, solvent, capping agents) for morphology and phase control.
- Evaluation of electrochemical and electrocatalytic properties, focusing on OER/HER performance and supercapacitor efficiency.
- Analysis of the effect of cationic disorder and stoichiometric variation on ternary thiospinel performance.
Excerpt from the Book
1.1. General introduction
Nanotechnology in recent years has brought a revolution in the mindset of the materials sciences community, with different materials exhibiting interesting properties at the nano-scale size regime. Generally, the field focuses on the understanding and control of matter at nano-scale dimensions between 1 nm to 100 nm. The resulting nanomaterials (consisting of nanoparticles, nanorods, nanowires, nanoflowers), depending on the morphology of the materials, would portray unique optoelectronic, magnetic, and physicochemical properties when compared to their bulk counterparts [1, 2]. Thus, these properties lead to exploitation in diverse novel applications. As a result, control and manipulation of particle size and shape at the nanometer scale have been identified as the key driving force in the field of nanotechnology [3].
The synthesis protocols of nanomaterials have been dominated by two approaches, namely the bottom-up approach and top-down approach. The former is a typical self-assembly process through a nucleation mechanism at the atomic level, whereas the latter is concerned with the breaking down (mostly a physical process) of bulk materials to afford nanostructures. Regardless of the type of approach, the breakthrough in nanotechnology over recent years has been advocated predominantly by the synthesis of colloidal quantum dots [4]. As a result, it is mostly common that synthesizing monodispersed nanostructures with well-defined morphology and properties, scaling up for green industrial production, and more understanding on the tuning of physical-chemical related properties, are likely to be the main current trends in nanotechnology research projects [5].
Transition metal sulfide (TMS) nanomaterials, a class of metal chalcogenides, have been recognized for their rich structural diversities in applications. They receive considerable attention due to their interesting electronic and magnetic properties. Furthermore, they are relatively cheap and abundant; most occur naturally in different mineral forms [6]. Such nanomaterials, including thin films, have been widely researched in fields focusing on photovoltaic technologies, semiconductors, telecommunication, bioimaging and solar cells, amongst others [7, 8].
Summary of Chapters
CHAPTER ONE: INTRODUCTION AND LITERATURE REVIEW: This chapter provides an overview of nanotechnology, transition metal sulfide nanomaterials, and the utilization of single-source precursors for their fabrication.
CHAPTER TWO : SYNTHESIS OF RARE PURE PHASE Ni3S4 AND Ni3S2 NANOPARTICLES IN DIFFERENT PRIMARY AMINE COORDINATING SOLVENTS: This chapter covers the synthesis and characterization of nickel dithiocarbamate complexes and their application in creating specific nickel sulfide nanoparticle phases.
CHAPTER THREE: HETEROCYCLIC DITHIOCARBAMATO-NICKEL(II) COMPLEXES SINGLE MOLECULAR PRECURSORS FOR NICKEL SULFIDE THIN FILMS: This chapter details the use of specific nickel complexes to deposit nickel sulfide thin films using the Aerosol Assisted Chemical Vapour Deposition (AACVD) technique.
CHAPTER FOUR : FACILE SYNTHESIS OF BIFUNCTIONAL CoxSy NANOPLATES FOR EFFICIENT H2/O2 EVOLUTION AND SUPERCAPACITANCE: This chapter reports the synthesis of cobalt dithiocarbamate complexes and their use in developing bifunctional materials for water splitting and energy storage.
CHAPTER FIVE: EFFECT OF CATIONIC DISORDER ON THE ENERGY GENERATION AND ENERGY STORAGE APPLICATIONS OF NixCO3-xS4 THIOSPINEL: This chapter examines the influence of stoichiometric metal variations in ternary thiospinel nanosheets on their electrocatalytic and electrochemical performance.
CHAPTER SIX: SUMMARY OF WORK AND FUTURE OUTLOOK: This chapter concludes the thesis by summarizing findings and proposing potential avenues for future research.
Keywords
Nanotechnology, Transition Metal Sulfides, Dithiocarbamate complexes, Single Source Precursor, Nanoparticles, Thin films, Water splitting, Hydrogen Evolution Reaction, Oxygen Evolution Reaction, Supercapacitors, Ni3S4, Ni3S2, NiCo2S4, Thiospinel, Chemical Vapour Deposition
Frequently Asked Questions
What is the core focus of this research?
The research focuses on the synthesis and characterization of heterocyclic dithiocarbamate complexes of nickel and cobalt to act as single-source precursors for the fabrication of binary and ternary metal sulfide nanomaterials.
What are the primary application areas for these materials?
The fabricated materials are primarily evaluated for their efficiency in energy generation (hydrogen and oxygen evolution reactions) and energy storage (supercapacitors) applications, as well as their magnetic properties.
What is the main objective of using these specific precursors?
The use of single-source molecular precursors aims to provide an efficient and controlled route to produce nanomaterials with desired stoichiometry, phase purity, and well-defined morphology, avoiding the complexities of using multiple-source methods.
Which scientific methods are central to this work?
Key methods include solvent thermolysis for nanoparticle synthesis, Aerosol Assisted Chemical Vapour Deposition (AACVD) for thin film deposition, and various characterization techniques like XRD, TEM/HRTEM, XPS, and electrochemical testing (CV, GCD, EIS).
What is covered in the main body of the work?
The main body details the synthesis of specific nickel and cobalt complexes, the influence of reaction parameters like temperature and capping agents on the resulting nanomaterial structure, and the performance testing of these materials in catalytic and energy storage contexts.
What are the characteristic keywords for this thesis?
The key themes are characterized by keywords such as Nanotechnology, Transition Metal Sulfides, Dithiocarbamate complexes, Single Source Precursor, Hydrogen Evolution Reaction (HER), Oxygen Evolution Reaction (OER), and Supercapacitors.
How does cationic disorder affect the performance of ternary materials?
In Chapter 5, the research demonstrates that stoichiometric variations (cationic disorder) in thiospinel Ni-Co-S materials significantly influence their electrical conductivity and catalytic performance, with nickel-rich compositions often showing superior energy efficiency.
Why are Ni-Co-S ternary systems preferred over binary counterparts?
The research highlights that the ternary Ni-Co-S systems exhibit synergistic effects from the combination of nickel and cobalt ions, leading to improved electrical conductivity and electrochemical performance compared to the individual binary metal sulfides.
- Arbeit zitieren
- Charles Gervas (Autor:in), 2022, Nickel and Cobalt Sulfide Nanomaterials for Magnetic and Energy Applications, München, GRIN Verlag, https://www.grin.com/document/1194519
