CONTENTS PREFACE 1. INTRODUCTION 1.1 Metal Oxides 1 1.2 Review of the methods and applications of metal/mixed metal oxides of transition metals 1.2.1 Catalyst 8 1.2.2 Photo catalyst 21 1.2.2 Sensors 30 1.2.4 Superconductors 40 1.2.5 Adsorbents 47 1.2.6 Ceramics 60 1.2.7 Fuels 71 1.3 REFERENCES 85 2. EXPERIMENTAL 2.1 Materials used 108 2.2 Equipment used 2.3 Calibration of ph meter 109 2.4 Synthesis of nanosized metal oxides 109 2.5 CHACTERIZATION TECHNIQE 111 2.5.1Powder X-Ray Diffraction 112 2.5.2 Magnetic Measurement 113 2.5.3 TGA/DTA 113 2.5.4 SEM 115 2.5.5 TEM 116 iv
CHAPTER 3: SYNTHESIS AND CHARACTERISATION OF NANOSIZED METAL OXIDES (RESULTS AND DISCUSSION 3.1 A simple and effective method of the synthesis of Fe 2 O 3 nanoparticles 118 3.2 A simple and effective method of the synthesis of nanosized CuO particles 122 3.3 A simple and effective method of the synthesis of nanosized ZnO particles 125 3.4 A simple and effective method of the synthesis of nanosized NiO particles 128 3.4 References 155 CHAPTER4: SYNTHESIS AND CHARACTERISATION OF NANOSIZED FERRITES (RESULTS AND DISCUSSION 4.1 A simple and effective method of the synthesis of nanosized ZnFe 2 O 4 particles 162 4.2 A simple and effective method of the synthesis of single phase nanosized NiFe 2 O 4 particles 165 4.3 A simple and effective method of the synthesis of nanosized CuFe 2 O 4 particles169 4.4 References 197 CHAPTER5: SYNTHESIS AND CHARACTERISATION OF NANOSIZED MIXED FERRITES (RESULTS AND DISCUSSION 5.1 A simple and effective method of the synthesis of nanosized Ni 0.5 Zn 0.5 Fe 2 O 4 particles. 205 5.2 A simple and effective method of the synthesis of nanosized Ni 0.5 Cu 0.5 Fe 2 O 4 particles 208 5.3 A simple and effective method of the synthesis of nanosized Cu0.5Zn0.5Fe 2 O 4 particles 211 5.4 References 233 CHAPTER6 CONCLUSIONS 239-243 LIST OF PUBLICATIONS 244 v
LIST OF ABBREVIATIONS DTA Differential Thermal Analysis g Gram h Hours mg Milligram ml Milliliter MMO Mixed Metal Oxide PXRD Powder X-Ray Diffraction SEM Scanning Electron Microscopy TEM Transmission Electron Microscopy TGA Thermo gravimetric Analysis 0 C Degree Celsius vi
PREFACE This thesis describes the experimental studies carried out by the candidate on Synthesis and Characterization of some nanosized metal/mixwd metal oxides of some transition metals Chapter 1 deals with the importance for the synthesis of nanosized metal/mixed metal oxides of various metals. It describes the literature on the various types applicatios of metal/mixed metal oxides that were employed for the synthesis of mixed metal oxides in particular. The various applications of metal/mixed metal oxides as catalyst, photocatalyst, sensors, superconductors, adsorbents, ceramics and fuels have been discussed briefly. [1-422] Chapter 2 gives details about the various materials, preparation method and basis principles of various analytical techniques such as powder X-Ray Diffraction, Thermogravimetric Analysis and Differential Thermal Analysis (TGA and DTA), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM),Surface area measurements that have been employed for the current investigation of metal/ mixed metal oxides. In general most of nanosized metal/mixed metal oxides have been synthesized at 70 0 C and then calcined at higher temperature ranging from 500 and 600 0 C. The method used for synthesis of metal / mixed metal oxides is simple, cheap, easy, less time consuming and most reliable. Chapter 3 describes the results and discussion of various nanosized metal oxides of Cu, Zn, Fe and Ni. Characterization of metal oxides by using various analytical techniques such as powderd X-Ray Diffraction, Thermogravimetric Analysis and Differential Thermal Analysis (TGA and DTA), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and surface area measurements have been employed for the current investigation of metal oxides. In general most of metal /mixed metal oxides have been synthesized at 70 0 C as compared to the temperatures required for the solid state method of preparation. The method used for synthesis of metal oxides is simple, cheap, easy, less time consuming and most reliable. All metal oxides of transition metals were nanosized and found in good agreement of theoretical value of nanosized metal oxides. Chapter 4 describes the synthesis and characterization of nanosized scale of Nickel ferrite,copper Ferrite and Zinc Ferrite. ZnFe 2 O 4 nanoparticles with spinel structure are synthesized successfully by aqueous precipitation method by using ammonia as precipitating agent. From TEM study it is found that particles are having average size of 10-30 nm. Magnetic measurements show that ZnFe 2 O 4 is super paramagnetic in nature having saturation magnetization (Ms) value 50 emu/g. This method is advantageous over existing methods of vii
synthesis of nanoparticles because other methods require specialized instrumentation, highly skilled labour, expensive materials and methods. Therefore, the proposed precipitation method is very promising, easy and cheap and may have extensive applications. NiFe 2 O 4 nanoparticles with cubic structure have been synthesized successfully by aqueous precipitation method. TEM study show very fine nanoparticles of diameter 10-28 nm with average size of 20nm. VSM studies show ferromagnetic behavior of synthesized nanoparticles.xrd pattern of the sample shows nano crystalline nature of the sample. It has been observed that the material prepared is having lattice constant of 8.398A 0. The average particle size of synthesized ferrite were observed to the 20 nm which is well supported by SEM/TEM micrographs. Magnetic measurements show that CuFe 2 O 4 is super paramagnetic in nature having saturation magnetization (Ms) value 50 emu/g. The notable advantages are high yield of product less expensive, shorter reaction times, mild reaction, conditions and easy workup.this method is advantageous over existing methods of synthesis of nanoparticles because other methods require specialized instrumentation, highly skilled labour, expensive materials and methods. Therefore, the proposed precipitation method is very promising, easy and cheap and may have extensive applications. Chapter 5 describes the synthesis and characterization of nanosized scale of Nickel ferrite,copper Ferrite and Zinc Ferrite. Ni 0.5 Zn 0.5 Fe 2 O 4 nanoparticles with cubic spinel structure are synthesized successfully by aqueous precipitation method. From TEM study it is found that particles are having size of 20-40 nm with average size. Magnetic measurements show that Ni 0.5 Zn 0.5 Fe 2 O 4 is super paramagnetic in nature having saturation magnetization (Ms) value 29 emu/g. This method is advantageous over existing methods of synthesis of nanoparticles because other methods require specialized instrumentation, highly skilled labour, expensive materials and methods. Ni 05 Cu 0.5 Fe 2 O 4 nanoparticle with cubic spinel structure have been synthesized successfully by aqueous precipitation method. From SEM/TEM studies it is found that particles have average size 18-34nm. Magnetic measurements shows that Ni 05 Cu 0.5 Fe 2 O 4 is super paramagnetic in nature having saturation magnetization (MS) value 52 emu/g. Cu 05 Zn 0.5 Fe 2 O 4 nanoparticle with cubic spinel structure are synthesized successfully by aqueous precipitation method. From TEM studies it is found that particles have average size 18-68nm. Magnetic measurements shows that Cu 05 Zn 0.5 Fe 2 O 4 is super paramagnetic in nature having saturation magnetization (MS) value 51 emu/g. This method is beneficial over the existing methods of synthesis of nano particles because other methods require expensive materials, highly skilled labour and specialized instrumentation. Therefore, viii
the proposed precipitation method is cheaper, easier, very promising and may have extensive applications. Chapter6 describes the conclusions of the work done. ix
LIST OF TABLES Table Description Page No. 2.1 List of various chemicals used in experimental work 108 3.1 X-Ray diffraction data for iron oxide 130 3.2 Observation on magnetic susceptibilities of synthesized nickel oxide 131 3.3 Observations of weight loss for iron oxide at corresponding temperature range 131 3.4 Particle size of synthesized iron oxide at different scales 132 3.5 Magnetic susceptibility data of iron oxide 133 3.6 X-Ray diffraction data for copper oxide 134 3.7 Observation on magnetic susceptibilities of synthesized copper oxide 135 3.8 Observations of weight loss for copper oxide at corresponding temperature range 135 3.9 Particle size of synthesized copper oxide at different scales 136 3.10 X-Ray diffraction data for zinc oxide 137 3.11 Observations of weight loss for zinc oxide at corresponding temperature range 138 3.12 Particle size of synthesized zinc oxide at different scales 138 3.13 X-Ray diffraction data for nickel oxide 139 3.14 Observation on magnetic susceptibilities of synthesized nickel oxide 139 3.15 Observations of weight loss for nickel oxide at corresponding temperature range 139 4.1 X-Ray diffraction data for zinc ferrite 172 4.2 Reported value of saturation magnetization in literature 173 4.3 Observations of weight loss for zinc ferrite at corresponding temperature range 174 4.4 Particle size of synthesized zinc ferrite at different scales 174 4.5 X-Ray diffraction data for nickel ferrite 175 4.6 Size and magnetic parameters for synthesized nickel ferrite 176 4.7 Size and magnetic parameters for synthesized nickel ferrite 176 4.8 Observations of weight loss for nickel ferrite at corresponding temperature range 177 4.4 Particle size of synthesized nickel ferrite at different scales 177 4.5 X-Ray diffraction data for copper ferrite 178 4.8 Observations of weight loss for copper ferrite at corresponding temperature range 181 4.4 Particle size of synthesized copper ferrite at different scales 181 5.1 X-Ray diffraction data for nickel zinc ferrite 214 5.2 Reported value of saturation magnetization in literature 215 5.3 Observations of weight loss for nickel zinc ferrite at corresponding temperature 216 range 5.4 Particle size of synthesized nickel zinc ferrite at different scales 216 5.5 X-Ray diffraction data for nickel copper ferrite 217 5.6 Observations of weight loss for nickel copper ferrite at corresponding temperature 218 range 5.7 Particle size of synthesized nickel copper ferrite at different scales 218 5.8 X-Ray diffraction data for copper Zinc ferrite 219 5.9 Observations of weight loss for copper zinc ferrite at corresponding temperature 221 range 5.10 Particle size of synthesized copper zinc ferrite at different scales 221 x
LIST OF FIGURES Figure No. Description Page No. 3.1 XRD spectra of synthesized iron oxide 140 3.2 (a) Morin transition curve for synthesized iron oxide nanoparticles. 140 (b) VSM studies of synthesized iron oxide. 3.3 TGA/DTA curve of iron oxide heated at 70 o C 141 3.4 SEM images of iron oxide particles 142 3.5 TEM images of iron oxide particles 143-144 3.6 XRD spectra of synthesized copper oxide 150 3.7 VSM images of copper oxide particles 145 3.8 TGA-DTA images of copper oxide particles 146 3.9 SEM images of copper oxide particles 146 3.10 TEM images of copper oxide particles 147 3.11 X-ray diffraction patterns of calcined zinc oxide 148 3.12 Manetic measurements of synthesized ZnO 148 3.13 TGA-DTA graph of zinc oxide. 149 3.14 SEM Micrographs of zinc oxide 150 3.15 TEM micrograph of zinc oxide under high magnification (Scale bar is 20 nanometer 151 3.16 XRD spectra of synthesized nickel oxide 152 3.17 Manetic measurements of synthesized ZnO 152 3.18 TGA/DTA curve of nickel oxide heated at 70 o C 153 3.19 SEM micrographs of nickel Oxide particles 153 3.20 TEM micrographs of nickel oxide particles 154 4.1 XRD spectra of Zinc Ferrite 182 4.2 Magnetic measurement of synthesized Zinc ferrite particles 183 4.3 TGA-DTA of zinc ferrite particles 184 4.4 SEM images of zinc ferrite 185 4.5 TEM images of zinc ferrite nanoparticles 186 4.6 XRD spectra of nickel ferrite 187 4.7 Magnetic measurements of nickel ferrite nanoparticles 187 4.8 TGA-DTA of nickel ferrite particles 188 4.9 SEM images of nickel ferrite 189 4.10 TEM images of nickel ferrite nanoparticles 190-2 4.11 XRD spectra of copper ferrite 193 4.12 Magnetic measurement of synthesized copper ferrite particles 194 4.13 TGA-DTA of copper ferrite particles 194 4.14 SEM images of copper ferrite particles 195 4.15 TEM images of copper ferrite particles 196 5.1 XRD spectra of Ni 05 Zn 0.5 Fe 2 O 4 222 5.2 Magnetic measurement of synthesized Ni 05 Zn 0.5 Fe 2 O 4 Particles 222 5.3 TGA-DTA of Ni 05 Zn 0.5 Fe 2 O 4 Particles 224 5.4 SEM micrographs of Ni 05 Zn 0.5 Fe 2 O 4 Particles 224 5.5 TEM images of Ni 05 Zn 0.5 Fe 2 O 4 particles 225 5.6 X-Ray diffraction spectra of Ni 05 Cu 0.5 Fe 2 O 4 Particles 226 5.7 Magnetic measurement of synthesized Ni 05 Cu 0.5 Fe 2 O 4 Particles 227 5.8 TGA-DTA of Ni 05 Cu 0.5 Fe 2 O 4 Particles 228 5.9 SEM micrographs of Ni 05 Cu 0.5 Fe 2 O 4 Particles 228 5.10 TEM micrographs of Ni 05 Cu 0.5 Fe 2 O 4 Particles 229 5.11 X-Ray diffraction spectra of Cu 05 Zn 0.5 Fe 2 O 4 Particles 230 5.12 Magnetic measurement of synthesized Cu 05 Zn 0.5 Fe 2 O 4 particles 230 5.13 TGA-DTA of Cu 05 Zn 0.5 Fe 2 O 4 Particles 231 5.14 SEM micrograph of Cu 05 Zn 0.5 Fe 2 O 4 Particles 231 5.15 TEM micrographs Cu 05 Zn 0.5 Fe 2 O 4 particles 232 xi
xii