Chapter 1 Metal Oxide Nanomaterial Gas Sensors:Introduction and Applications 1
1.1 Survey of Gas Sensors 1
1.2 Classification of Gas Sensors 3
1.2.1 Methods Based on Electrical Variation with Different Materials 4
1.2.2 Methods Based on Variation of Other Properties 12
1.2.3 Summary and Comparison for Different Gas Sensing Methods 18
1.3 Application and Perspective of Metal Oxide Nanomaterial Gas Sensors 20
References 22
Chapter 2 Basic Theory of Metal Oxide Semiconductor Gas Sensors 34
2.1 Gas Sensing Mechanism 34
2.2 Reaction between Gases and Metal Oxide Semiconductor Gas Sensors 38
2.3 Effect of Noble Metal Doping 39
2.4 Microstructure Model of Metal Oxide Sputtered Films 41
2.5 Growth Mechanisms of Nanowires 43
2.5.1 Vapour-Liquid-Solid(VLS)Mechanism 43
2.5.2 Vapour-Solid(VS)Mechanism 44
References 46
Chapter 3 Fabrication Techniques of Metal Oxide Nanomaterials 48
3.1 Physical Vapour Deposition(PVD) 48
3.2 Chemical Vapour Deposition(CVD) 49
3.3 Sol-Gel 50
3.4 Spray Pyrolysis 51
3.5 Screen Printing 53
3.6 Drop Coating 53
3.7 Comparison of Different Fabrication Techniques 54
References 56
Chapter 4 Characterization Techniques of Metal Oxide Nanomaterials 59
4.1 X-ray Diffraction 59
4.2 Scanning Electron Microscopy 61
4.3 Transmission Electron Microscopy 63
4.4 X-ray Photoelectron Spectroscopy 67
4.5 Scanning Probe Microscopy 68
4.6 Physical Adsorption Isotherm Method 71
4.7 Film Density 73
4.8 Other Characterization Techniques 73
4.9 Measurement of Gas Sensing Properties 74
References 76
Chapter 5 SnO2-based Nanomaterial Gas Sensors 78
5.1 SnO2 Thin Films 78
5.1.1 Preparation 78
5.1.2 Microstructure 80
5.1.3 Gas Sensing Properties 89
5.2 SnO2 Nanowires 104
5.2.1 Preparation 104
5.2.2 Microstructure 105
5.2.3 Gas Sensing Properties 111
5.3 SnO2 Nanorods 122
5.3.1 Preparation 122
5.3.2 Microstructure 122
5.3.3 Gas Sensing Properties 125
References 129
Chapter 6 WO3-based Nanomaterial Gas sensors 134
6.1 WO3 Thin Films 134
6.1.1 Preparation 134
6.1.2 Microstructure 137
6.1.3 Gas Sensing Properties 143
6.2 WO3 Nanowires 153
6.2.1 Preparation 153
6.2.2 Microstructure 154
6.2.3 Gas Sensing Properties 156
6.3 WO3 Nanoparticles 161
6.3.1 Preparation 161
6.3.2 Microstructur 162
6.3.3 Gas Sensing Properties 163
References 170
Chapter 7 Future of Metal Oxide Nanomaterial Gas Sensors 174
7.1 Material Design for Metal Oxide Nanomaterial Gas Sensors 174
7.2 For Innovations of Metal Oxide Nanomaterial Gas Sensors 174
7.2.1 Innovative Sensors 176
7.2.2 Intelligent Sensors 176
7.2.3 Hybrid Systems 177
Reference 178