Physical Chemistry of Solid-Gas Interfaces: Concepts and Methodology for Gas Sensor Development

Physical Chemistry of Solid-Gas Interfaces......Page 5
Table of Contents......Page 7
Preface......Page 15
1.1. The surface of solids: general points......Page 17
1.2. Illustration of adsorption......Page 18
1.2.1. The volumetric method or manometry......Page 19
1.3.1. Van der Waals forces......Page 20
1.3.2. Expression of the potential between a molecule and a solid......Page 22
1.3.3. Chemical forces between a gas species and the surface of a solid......Page 23
1.4.1. The different models of adsorption......Page 24
1.4.2. The Hill model......Page 25
1.4.4.1. Formulating the equilibrium......Page 26
1.4.4.2. Isotherm equation......Page 27
1.4.5. Thermodynamics of adsorption equilibrium in the Hill-Everett model......Page 28
1.5.1. General points......Page 29
1.5.3. Adsorption isotherms of localized monolayers......Page 31
1.5.3.1. Thermodynamic method......Page 32
1.5.3.2. The kinetic model......Page 33
1.5.4.1. Isotherm equation......Page 34
1.6. Chemical adsorption isotherms......Page 39
1.7. Bibliography......Page 43
2.1. The concept of phases......Page 45
2.2. Solid solutions......Page 47
2.3. Point defects in solids......Page 49
2.4. Denotation of structural members of a crystal lattice......Page 50
2.5.1. Formation of defects in a solid matrix......Page 52
2.5.2. Formation of defects involving surface elements......Page 53
2.6. Bibliography......Page 54
3.2. Electronic properties of gases......Page 55
3.3.1. Introduction......Page 56
3.3.2.1. Reminder about quantum mechanics principles......Page 57
3.3.2.2. Band diagrams of solids......Page 61
3.3.2.3. Effective mass of an electron......Page 68
3.4.1. Full bands......Page 71
3.4.2. Partially occupied bands......Page 72
3.5.1. Band diagram and Fermi level of conductors......Page 73
3.5.2. Case of intrinsic semiconductors......Page 77
3.5.3. Case of extrinsic semiconductors......Page 78
3.5.4. Case of materials with point defects......Page 80
3.5.4.1. Metal oxides with anion defects, denoted by MO1–x......Page 81
3.5.4.2. Metal oxides with cation vacancies, denoted by M1–xO......Page 82
3.5.4.4. Metal oxides with interstitial anions, denoted by MO1+x......Page 83
3.6. Bibliography......Page 84
4.1. Introduction......Page 85
4.2. Interfacial phenomena......Page 86
4.3. Solid-gas equilibriums involving electron transfers or electron holes......Page 87
4.3.1. Concept of surface states......Page 88
4.3.2. Space-charge region (SCR)......Page 89
4.3.3.1. Case of a semiconductor in the absence of surface states......Page 93
4.3.3.2. Case of a semiconductor in the presence of surface states......Page 94
4.3.3.3. Physicists’ and electrochemists’ denotation systems......Page 95
4.3.4.1. Influence of adsorption on the surface barrier VS......Page 96
4.3.4.2. Influence of adsorption on the dipole component VD......Page 106
4.4. Solid-gas equilibriums involving mass and charge transfers......Page 107
4.4.1. Solids with anion vacancies......Page 108
4.4.3. Solids with interstitial anions......Page 110
4.4.4. Solids with cation vacancies......Page 112
4.5. Homogenous semiconductor interfaces......Page 113
4.5.1. The electrostatic potential is associated with the intrinsic energy level......Page 119
4.5.2. Electrochemical aspect......Page 120
4.6. Heterogenous junction of semiconductor metals......Page 123
4.7. Bibliography......Page 124
5.1. General points on process kinetics......Page 125
5.1.1. Linear chain......Page 127
5.1.1.1. Pure kinetic case hypothesis......Page 130
5.1.1.2. Bodenstein’s stationary state hypothesis......Page 134
5.1.1.3. Evolution of the rate according to time and gas pressure......Page 135
5.1.1.4. Diffusion in a homogenous solid phase......Page 137
5.1.2. Branched processes......Page 141
5.2. Electrochemical aspect of kinetic processes......Page 142
5.3. Expression of mixed potential......Page 149
5.4. Bibliography......Page 152
6.1. Introduction......Page 153
6.2.1. General points......Page 154
6.2.1.2. Seebeck effect......Page 155
6.2.1.4. Tian equation......Page 156
6.2.1.5. Description of a Tian-Calvet device......Page 158
6.2.1.6. Thermogram profile......Page 160
6.2.1.7. Examples of applications......Page 162
6.3.1. Introduction......Page 172
6.3.2. Theoretical aspect......Page 173
6.3.3.1. Tin dioxide......Page 177
6.3.3.2. Nickel oxide......Page 179
6.4.1. Contact potential difference......Page 188
6.4.2.2. Theoretical study of the vibrating capacitor method......Page 192
6.4.3.2. Temperature conditions......Page 195
6.4.4.1. The reference electrode......Page 197
6.4.5. Display of experimental results......Page 198
6.4.5.1. Study of interactions between oxygen and tin dioxide......Page 200
6.4.5.2. Study of interactions between oxygen and beta-alumina......Page 201
6.5.1. General points......Page 203
6.5.2. Direct-current measurement......Page 205
6.5.3.2. Principle of the impedance spectroscopy technique......Page 207
6.5.4.1. Protocol......Page 212
6.5.4.2. Experimental results: characteristics specific to each material......Page 213
6.5.5. Evolution of electrical parameters according to temperature......Page 218
6.5.6. Evolution of electrical parameters according to pressure......Page 224
6.6. Bibliography......Page 228
7.1. Introduction......Page 231
7.2.1.1. Elaboration process and structural properties......Page 232
7.2.1.2. Influence of the morphological parameters on the electric properties......Page 233
7.2.2.1. Experimental device......Page 235
7.2.2.3. Thickness measure......Page 238
7.2.2.5. Structure and properties of the films......Page 240
7.2.3.1. General points......Page 252
7.2.3.2. Device description......Page 254
7.2.3.3. Structural characterization of the material......Page 258
7.2.3.4. Influence of the experimental parameters on the physico-chemical properties of the films......Page 261
7.2.3.5. Influence of the structure parameters on the electric properties of the films......Page 266
7.2.4.1. Method description......Page 268
7.2.4.2. Ink elaboration......Page 269
7.2.4.3. Structural characterization of thick films made with tin dioxide......Page 270
7.3.1. General properties......Page 271
7.3.2. Material elaboration......Page 273
7.3.3.1. Mono-axial compression......Page 277
7.3.3.2. Serigraphic process......Page 278
7.3.4.1. Physico-chemical characterization of the sintered materials......Page 279
7.3.4.2. Physico-chemical treatment of the thick films......Page 282
7.3.5. Electric characterization......Page 289
7.4. Bibliography......Page 291
8.1. Introduction......Page 293
8.2.1. Methods to deposit the metallic parts on the sensitive element......Page 294
8.2.2. Role of the metallic elements on the sensors’ response......Page 295
8.2.3. Role of the metal: catalytic aspects......Page 298
8.2.3.1. Spill-over mechanism......Page 299
8.2.3.3. Electronic effect mechanism......Page 300
8.2.3.4. Influence of the metal nature on the involved mechanism......Page 302
8.3.1. Choice of the samples......Page 304
8.3.2. Description of the reactor......Page 305
8.3.3.1. Influence of the oxygen pressure on the electric conductivity......Page 307
8.3.3.2. Influence of the reducing gas on the electric conductions......Page 311
8.4. Case study: beta-alumina......Page 312
8.4.1. Device and experimental process......Page 313
8.4.2. Influence of the nature of the electrodes on the measured voltage......Page 314
8.4.2.1. Study of the different couples of metallic electrodes......Page 315
8.4.2.2. Electric response to polluting gases......Page 317
8.4.3.1. Description of the studied devices......Page 319
8.4.3.2. Study of the electric response according to the experimental conditions......Page 320
8.5. Conclusion......Page 322
8.6. Bibliography......Page 323
9.1. General points on development and use......Page 325
9.2.1. Sensors elaborated using sintered materials......Page 326
9.2.2. Sensors produced with serigraphed sensitive materials......Page 328
9.3. Device designed for the laboratory assessment of sensitive elements and/or sensors to gas action......Page 332
9.3.1. Measure cell for sensitive materials......Page 333
9.3.3.1. Measure of the electric conductance......Page 335
9.4.1. Assessment of the performances of tin dioxide in the presence of gases......Page 338
9.4.2.2. Electric response to the action of oxygen......Page 343
9.4.3.2. Electric results......Page 345
9.5. Assessment of the sensor working for an industrial application......Page 348
9.5.1.2. Study of performances in the presence of hydrogen......Page 349
9.5.1.3. Test carried out in an industrial environment......Page 353
9.5.2. Application of the resistant sensor to atmospheric pollutants in an urban environment......Page 357
9.5.2.1. Measurement campaign conducted at Lyon in 1988......Page 358
9.5.2.2. Measurement campaign conducted at Saint Etienne in 1998......Page 361
9.5.3.1. Strategy implemented to control the emission of nitrogen oxides......Page 363
9.5.3.2. Strategy implemented to control nitrogen oxide traps......Page 365
9.5.3.3. Results relative to the nitrogen oxides traps......Page 366
9.6.1.1. Development of a sensor using a rhodium filter......Page 368
9.6.1.2. Development of a sensor using a platinum filter......Page 370
9.6.2.2. Development of a protective film for potentiometric sensors......Page 372
9.7. Bibliography......Page 375
10.1. Introduction......Page 377
10.2. Nickel oxide......Page 378
10.2.1. Kinetic model......Page 381
10.2.2.1. Simulation of the curves displaying a maximum......Page 386
10.2.2.2. Simulation of the curves displaying a plateau......Page 393
10.3.1.1. Oxygen species present at the surface of the device......Page 396
10.3.1.2. Origin of the electric potential......Page 400
10.3.2.1. The electrode potential......Page 401
10.3.2.2. Expression of the coverage degree......Page 405
10.3.2.3. Expression of the theoretical potential difference at the poles of the device......Page 410
10.3.3.1. Behavior as a function of temperature and pressure......Page 411
10.3.3.2. Behavior as a function of electrode size......Page 413
10.3.3.3. Evolution of the surface potential......Page 415
10.3.4.1. Description of the mechanisms considered......Page 417
10.3.4.2. Oxidation mechanisms of carbon monoxide......Page 418
10.3.4.3. Results of the simulation......Page 421
10.4.1. Introduction......Page 425
10.4.2. Proposition for a physico-chemical model......Page 426
10.4.3. Phenomenon at the electrodes and role of the thickness of the sensitive film......Page 431
10.4.3.1. Calculation of the conductance G as a function of the thickness of the film......Page 432
10.4.3.2. Mathematical simulation......Page 439
10.5. Bibliography......Page 444
Index......Page 447