FORMATION OF IRON OXIDE NANOWIRES BY USING THERMAL OXIDATION OF IRON NUR SYAFINI BINTI SA AD B

Transcription

1 FORMATION OF IRON OXIDE NANOWIRES BY USING THERMAL OXIDATION OF IRON NUR SYAFINI BINTI SA AD B UNIVERSITI TEKNIKAL MALAYSIA MELAKA 2015

2 B BACHELOR OF MANUFACTURING ENGINEERING (ENGINEERING MATERIALS) (HONS.) 2015 UTeM

3 UNIVERSITI TEKNIKAL MALAYSIA MELAKA FORMATION OF IRON OXIDE NANOWIRES BY USING THERMAL OXIDATION OF IRON This report submitted in accordance with requirement of the Universiti Teknikal Malaysia Melaka (UTeM) for the Bachelor Degree of Manufacturing Engineering (Engineering Materials)(Hons.) by NUR SYAFINI BINTI SA AD B FACULTY OF MANUFACTURING ENGINEERING 2015

4 UNIVERSITI TEKNIKAL MALAYSIA MELAKA BORANG PENGESAHAN STATUS LAPORAN PROJEK SARJANA MUDA TAJUK: Formation of Iron Oxide Nanowires by Using Thermal Oxidation of Iron SESI PENGAJIAN: 2014/15 Semester2 Saya NUR SYAFINI BINTI SA AD mengaku membenarkan Laporan PSM ini disimpan di Perpustakaan Universiti Teknikal Malaysia Melaka (UTeM) dengan syarat-syarat kegunaan seperti berikut: 1. Laporan PSM adalah hak milik Universiti Teknikal Malaysia Melaka dan penulis. 2. Perpustakaan Universiti Teknikal Malaysia Melaka dibenarkan membuat salinan untuk tujuan pengajian sahaja dengan izin penulis. 3. Perpustakaan dibenarkan membuat salinan laporan PSM ini sebagai bahan pertukaran antara institusi pengajian tinggi. 4. **Silatandakan ( ) SULIT TERHAD TIDAK TERHAD (Mengandungi maklumat yang berdarjah keselamatan atau kepentingan Malaysia sebagaimana yang termaktub dalam AKTA RAHSIA RASMI 1972) (Mengandungi maklumat TERHAD yang telah ditentukan oleh organisasi/badan di mana penyelidikan dijalankan) Disahkanoleh: AlamatTetap: Lorong Mesin Padi Kampung Alor Limbat Marang, Terengganu Tarikh: 30 Jun 2015 Cop Rasmi: Tarikh: 30 Jun 2015 **Jika Laporan PSM ini SULIT atau TERHAD,sila lampirkan surat daripada pihak berkuasa/organisasi berkenaan dengan menyatakan sekali sebab dan tempoh laporan PSM ini perlu dikelaskan sebagai SULIT atau TERHAD.

5 DECLARATION I hereby, declared this report entitled Formation of Iron Oxide Nanowires by Using Thermal Oxidation of Iron is the results of my own research except as cited in references. Signature : Author s Name : NUR SYAFINI BINTI SA AD Date : 30 Jun 2015

6 APPROVAL This report is submitted to the Faculty of Manufacturing Engineering of UTeM as a partial fulfillment of the requirements for the degree of Bachelor of Manufacturing Engineering (Engineering Materials) (Hons.). The member of the supervisory is as follow: (Project Supervisor)

7 ABSTRAK Oksida ferum nanowires digunakan secara meluas dalam pelbagai aplikasi, termasuklah fotopemangkinan. Konvensional, oksida ferum nanowires dihasilkan oleh teknik-teknik seperti; proses sol-gel, kaedah templat, penguraian terma, proses hidroterma Walau bagaimanapun, teknik-teknik ini mahal dan rumit. Oleh itu, projek ini bertujuan untuk menghasilkan oksida ferum nanowires dengan menggunakan pengoksidaan terma ferum. Beberapa paremeter telah disiasat seperti kesan masa pengoksidaan, suhu pengoksidaan dan keadaan pada substrat. Morfologi dan fasa Fe 2 O 3 nanowires yang dibentuk telah disifatkan. Pemerhatian FESEM telah menunjukkan bahawa Fe 2 O 3 struktur nanowires telah terbentuk pada kepingan Fe tulen. XRD dan spektroskopi Raman mengesahkan fasa fasa: α- Fe 2 O 3, FeO dan Fe 3 O 4 terbentuk selepas process pengoksidaan manakala EDX digunakan untuk memastikan nanowires yang terhasil mempunyai oksigen dan ferum. Raman spektroskopi telah digunakan untuk menyokong morfologi dan fasa yang diperoleh dari analisis SEM dan XRD. Sampel (pengoksidaan pada 180 min, 500 C, dalam udara tanpa menitikkan asid sulfurik) adalah tertakluk kepada ujian degradasifoto di bawah cahaya UV. Hasil daripada degradasifoto ini menunjukkan semakin lama masa larutan methyl orange terdedah kepada cahaya UV, semakin pudar larutan itu. Untuk memastikan larutan itu mempunyai perubahan warna, analisis menggunakan UV visible digunakan. Berdasarkan keputusan yang diperoleh, maka boleh disimpulkan bahawa larutan itu berlaku proses degradasi apabila masa pendedahan kepada cahaya semakin menigkat. i

8 ABSTRACT An iron oxide nanowire is used widely in a range of applications, which include photocatalysis. Conventionally, iron oxide nanowires are produced by techniques such as; sol-gel process, template method, thermal decomposition, hydrothermal process However, these techniques are costly and complicated. Hence, this project serves to fabricate the iron oxide nanowires by using thermal oxidation of iron. Several parameters were investigated such as the effect of oxidation time, oxidation temperature and condition on the substrate. The morphologies and phases of Fe 2 O 3 nanowires formed were characterized. FESEM observation showed that Fe 2 O 3 nanowires structure was successfully formed on pure Fe foil. XRD and Raman spectroscopy confirmed variant phase: α- Fe 2 O 3, FeO and Fe 3 O 4 occurred after oxidizing while EDX was used to confirm that the nanowires consisted of oxygen and iron. Raman spectroscopy was used to support the morphologies and phases observed by SEM and XRD. The samples (oxidized at 180 min, 500 C, in air without dropping sulphuric acid) were subjected to photodegradation testing under UV light conditions. The result obtain from this photodegradation shows that, as increase the time of methyl orange solution exposed to UV light, the solution is become fades. To ensure that the solution has changed color, UV visible analysis is used. Based on the results obtained, it can be concluded that the solution was effective degradation process when the time of exposure to light progressively increase. ii

9 DEDICATION Dedicated to my beloved family members especially my parents, lecturers, and also to all my friends. iii

10 ACKNOWLEDGEMENT I would like to take this opportunity to express my gratefulness and gratitude to those who have rendered their valuable advice, support and guidance to me during the long journey of completing this research. First and foremost, I would like to thank my supervisor Dr. Syahriza Ismail for her relentless support, advice and guidance throughout the entire project. Not to forget the research members: Azreen and Nadia for all the assistance and guidance provided all this while. I am greatly touched by the commitments and dedications they have shown. Without the support and guidance, I would not be able to complete this research. Besides, without the moral support and understanding from my family especially my father, En Saad Talib and my late mother, Pn Kelsom Musa, it would be impossible for me to complete this research. I wish to express my biggest gratefulness and love to my family members. Finally, I wish to say that I treasure very much the friendship of my friends who have been very supportive in providing all necessary help and advice during the journey of completing this research. iv

11 TABLE OF CONTENT Abstrak Abstract Dedication Acknowledgement Table of Content List of Tables List of Figures i ii iii iv v viii ix CHAPTER 1: INTRODUCTION 1.1 Background Problem Statement Research Objective Scopes of Work Project Outline 6 CHAPTER 2: LITERATURE REVIEW 2.1 Introduction to Nanostructure Metal Valve Oxide-iron Oxide: Polymorphs and Properties Technique to Produce Nanowires Hydrothermal process Sol-gel process Template-assisted electrodeposition Thermal decomposition Thermal oxidation Application of Iron Oxide Nanowires Catalyst 21 v

12 2.4.2 Photoelectrochemical cells Photocatalyst 24 CHAPTER 3: METHODOLOGY 3.1 Introduction Materials Design of Experiment Substrate preparation and cleaning Thermal oxidation process Thermal oxidation parameter Characterization Morphology characterization Scanning electron microscopy Structural characterization X-ray diffraction Electron dispersive X-ray Raman spectroscopy Photodegradation testing UV lamp chamber 34 CHAPTER 4: RESULTS AND DISCUSSIONS 4.1 Fe 2 O 3 Nanowires Formation by Thermal Oxidation Process Effect of growth time Effect of sulphuric acid on the morphology of samples Mechanism of Fe 2 O 3 Nanowires Formation Mechanism of Fe 2 O 3 nanostructure in air Mechanism of Fe 2 O 3 nanostructure in air by dropping H 2 SO X-Ray Diffraction (XRD) 43 vi

13 4.3.1 Different time effect Influence of H 2 SO 4 on the samples Raman Spectroscopy Analysis Effect of growth time Effect of sulphuric acid (H 2 SO 4 ) Effect of temperature Photodegradation Testing Mechanism of photodegradation 53 CHAPTER 5: CONCLUSIONS AND RECOMMENDATIONS 5.1 Conclusions Recommendations 56 REFERENCES 57 vii

14 LIST OF TABLES 2.1 Physical and Magnetic Properties of Iron Oxide The List of Materials Used in the Research List of Changing Parameter Raman shift of variant phases iron oxide that match Raman shift of iron oxide nanowires at 300 C, for 60 min Raman shift of variant phases iron oxide that match Raman shift of iron oxide nanowires at 300 C, for 180 min Raman shift of variant phases iron oxide that match Raman shift of iron oxide nanowires at 300 C, for 300 min Raman shift of variant phases iron oxide that match Raman shift of iron oxide nanowires at 180 min, for 300 C Raman shift of variant phases iron oxide that match Raman shift of iron oxide nanowires at 180 min, for 500 C Raman shift of variant phases iron oxide that match Raman shift of iron oxide nanowires at 180 min, for 700 C Sample used for photodegradation of methyl orange 51 viii

15 LIST OF FIGURES 1.1 Morphology of single nanowires Schematic diagram of single nanowires array Various synthesized method of nanowires Application of hematite nanowires Photocatalytic process Type of Nanomaterials structure (A) 0D spheres and clusters, (B) 1D nanofibers, wires, and rods, (C) 2Dfilms, plates, and networks, (D) 3D nanomaterials Typical SEM image of different types of 1D nanostructure, (A) nanowires, (B) nanorods, (C) nanotubes, (D) nanobelts, (E) nanoribbons, and (F) hierarchical nanostructure Crystal structure of magnetite (Fe 3 O 4 ) Crystal structure of hematite (α Fe 2 O 3 ) Crystal structure of maghemite (γ- Fe 2 O 3 ) Schematic diagram of hydrothermal process Schematic diagram of sol-gel process 15 ix

16 2.8 Schematic diagram of template-assisted electrodeposition 16 method 2.9 Schematic diagram of thermal decomposition method Schematic diagram of thermal oxidation process Step of iron oxide nanowire growth mechanism: 1)oxygen adsorption, 2)surface oxidization to form nuclei, 3)nuclei arrangement and 4)formation of nanowires The image of Fe substrates oxidize at two different temperatures, 20 (a) 400 C and (b) 600 C and the different type of layer form 2.13 The general catalytic cycle The change in activation energy brought about by a catalyst Mechanism of phoelectrochemical (PEC) cells Mechanism of photocatalyst reaction Flow chart of the experimental work Vacuum furnace setup tor thermal oxidation process Field emission SEM machine X-Ray diffraction (XRD) machine Equipment set-up for photodegradation of methyl orange 35 x

17 4.1 FESEM images of Fe 2 O 3 nanowires formed by thermal oxidation process within time (a) 60 min, (b)180 min and (c) 300 min at 300 C in air EDX spectra of Fe 2 O 3 nanowires formed FESEM images of samples synthesized by reaction of H 2 SO 4 with Fe at time (a) 60 min, (b) 180 min and (c) 300 min at 300 C in air Schematic stress-driven mechanism of Fe 2 O 3 nanowires growth via diffusion XRD patterns for Fe substrate formed by thermal oxidation process with time (a) 60 min, (b) 180 min and (c) 300 min at 300 C in air XRD patterns for Fe substrate formed by thermal oxidation process with pattern focused region of graph 2Ɵ= XRD patterns for Fe substrate formed by thermal oxidation 46 process with time at 300 C in air by dropping H 2 SO XRD patterns for Fe substrate formed by thermal oxidation process with pattern focused region of graph 2Ɵ= Raman spectrum for iron oxide nanowires formed by thermal oxidation process with time at 300 C in air Raman spectrum for iron oxide nanowires formed by thermal 49 oxidation process with time at 300 C in air. by dropping H 2 SO 4 xi

18 4.11 Raman spectrum for iron oxide nanowires formed by thermal oxidation process with temperature at 180 min in air Methyl orange solution degrade as time exposed to UV light UV-visible analysis at different time exposed to UV light. 53 xii

19 CHAPTER 1 INTRODUCTION This chapter describe the introduction of the project. In this project, thermal oxidation process was used to form iron oxide nanowires. This chapter also include background, problem statement, objective, scope and project outline of the study. 1.1 Background Nanostructure refers to materials system with at least one dimension is in the range of ~1-100nm. In a nanostructure, electrons are freely move in other dimension eventhough there are confined in nanoscale dimension. As compared to individual atom and molecules, the nanostructure is mostly unique. Nanowires and nanobelts are semi one dimensional nanostructure based oxides, they have pulled in much consideration lately. They show unordinary optical, electronic, attractive and mechanical properties as contrasted with those of mass materials. It is because of the huge surface related deformity starting from the high surface to volume degrees. Moreover, some paramount properties of one dimensional nanostructured based oxide are great high temperature steadiness, oxidation safety and stable electric properties. Thus, it demonstrates their potential basic building blocks for new classes of environmentally conscious electronics (Yang et al., 2010). Since the nanowires is studied, some paramount is important which are the control of morphology, size and growth direction. Figure 1.1 shows the morphology of nanowire (Hiralal et al., 2008a) while Figure 1.2 shows the schematic diagram of single nanowire arrays (Rahim et al., 2014). In addition, the different of 1

20 morphologies get will affect the properties with unique application. A suitable alignment of substrate is needed for an ensemble of nanowires (Wen et al., 2005). Figure 1.1: Morphology of single nanowires (Hiralal et al., 2008). Figure 1.2: Schematic diagram of single nanowire array (Rahim et al., 2014). Recently, nanowires have been synthesized by several different methods, such as the hydrothermal process, the template method, the vapour solid process, sol gel technique and thermal decomposition (Liu et al., 2008). Nevertheless, thermal oxidation in various oxidizing atmosphere is a most simple, cheap and direct 2

21 procedure to form iron oxide nanowires (Grigorescu et al., 2012) shows in Figure 1.3. Figure 1.3: Various synthesized method of nanowires. The growth of nanowires on the surface of iron is depending on the condition. Under typical condition, layer oxide will be formed, as hematite, magnetite and wustite. Hematite is formed at outer layer while magnetite as an intermediate layer and wustite layer form on iron iron substrate. As n-type semiconductor, which has bandgap 2.1 ev, hematite is environmental friendly, not poisonous, corrosion resistant and also the cost is low. Figure 1.4 shows the usage of hematite. 3

22 Figure 1.4: Application of hematite nanowires Among of these application, one of interesting is as photocatalyst (Figure 1.5). Photocatalytic reactions promoted by aqueous suspensions of nano sized transition metal oxides have been subject of abundant number of resent research (Bakardijeva et al., 2007) with the semiconductor performance, iron oxide is use in solar photoelectrolysis cells. Hematite is a good catalyst for photooxidation of sulphite. The details on this iron oxide will be reviewed in chapter 2. Figure 1.5: Photocatalytic process (Ctibor et al., 2013) 4

23 1.2 Problem Statement Since the time that Fujishima and Honda reported in 1972, TiO 2 photoelectrode methodology is utilized to create hydrogen from water. Ways and intends to utilize daylight as an essential vitality hotspot for hydrogen fuel era has been an exceptionally examined point in science and engineering, with a specific end goal to accomplish an upgraded daylight reaction, materials must have a suitably low band crevice and ready to part water, and additionally have suitable band edge positions in respect to the red-ox capability of water. Subsequently, hematite, with band hole of 2.1 ev has recovered solid examination enthusiasm to be utilized as terminal water part for hydrogen generation. These are because of the cost, less advanced yet plentiful materials. Moreover, because of the looked into that had being carried out, it demonstrated that, the examination about arrangement of iron oxide nanowires by utilizing warm oxidation system was very constrained. It is accepted that nanowires develop from tip while reactant (metal) diffuse by means of the surface from the metal substrate. However the accurate instrument of development is a long way from clear. All the more as of late, different gatherings have returned to the spontaneous development of oxide nanowires by warm oxidation of metallic substrates (Fe, Zn and Cu), despite the fact that a definite orderly study is needing. Photocatalytic response advanced by watery suspensions of nano estimated move metals oxide have been subject plenteous number of exploration (Bakardijeva et al., 2007). Iron oxide has been concentrated on broadly for utilization in sunlight based photoelectrolysis cells. Bamba et.al., (2006) considered the photocatalytic oxidation of a few dangers at TiO 2 and Fe 2 O 3, surfaces. They found that TiO2 powder is dynamic photocatalyst for cyanide oxidation, while no oxidation was watched for Fe 2 O 3. Recently a few studies exhibited the confirmation for photograph reactant arrangement of OH radicals. The era of OH radicals is attained through the usage of costly oxidants such ozone and H 2 O 2 often in mix, with or without UV radiation. Nonetheless, in this theory, the photocatalytic action of iron oxide got by warm oxidation technique which is this system is basic and immediate method. 5

24 1.3 Research Objectives This research is about the formation of iron oxide nanowires and followings are the objectives for this work: a) To produce the iron oxide nanowires formed by thermal oxidation b) To study the mechanism of iron oxide nanowires by thermal oxidation c) To study the photocatalysis of iron oxide formed by thermal oxidation 1.4 Scopes of Work This research covered the study on the formation of Fe 2 O 3 nanowires. For the synthesis of Fe 2 O 3 nanowires, thermal oxidation process was selected. For thermal oxidation process, the effect of temperature, condition on the substrate and time were studied. Besides, the photocatalytic application was also considered. Phase and morphology characterization on the Fe 2 O 3 nanowires was examined by using Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Electron Dispersive X-Ray Spectroscopy (EDX), Raman Spectroscopy, UV Visible Spectrometry and UV lamp chamber. 1.5 Project Outline This project was conducted to form the iron oxide nanowires structure by thermal oxidation process. This process was performed in vacuum furnace at temperature 300 C 700 C to form the nanowires. The photocatalytic ability of the formed oxides it tested by using the UV light irradiation. Chapter one is the introduction for this whole project while in the chapter two is explain about nanostructure materials, thermal oxidation process and also the 6