Structural dynamics of chlorinated ruthenium dioxide model catalysts under reaction conditions [Elektronische Ressource] / von Jan Philipp Hofmann

Hofmann, Jan Philipp

Informations

• Publié par: justus-liebig-universitat_giessen
• Publié le: 01 janvier 2009
• Nombre de lectures: 6
• Langue: English
• Poids de l'ouvrage: 11 Mo

Extrait

Structural Dynamics of Chlorinated
Ruthenium Dioxide Model
Catalysts under Reaction
Conditions
im Fachbereich Biologie und Chemie
der Justus-Liebig-Universität Gießen
zur Erlangung des Grades
Doktor der Naturwissenschaften
-Dr. rer. nat.-
genehmigte Inaugural-Dissertation
von
Diplom-Chemiker Jan Philipp Hofmann
aus Solms
Gießen, 20092
Betreuer und 1. Gutachter: Prof. Dr. Herbert Over
2. Gutachter: Prof. Dr. Jürgen Janek
Tag der Disputation: 16.12.2009
Prüfer: Prof. Dr. Claus-Dieter Kohl
Prüfer: Prof. Dr. Siegfried SchindlerPreface
“Es gibt kaum etwas, was gegen die Regeln echter Naturforschung mehr streitet,
als die Erfindung und der Gebrauch des Wortes Katalyse oder katalytische Kraft;
wir alle wissen, dass in diesem Worte keine Wahrheit liegt...”
(Zitat Justus von Liebig, around 1865)
Meiner Familie
34Contents
1 Motivation 11
I Applied Experimental and Theoretical Methods 15
2 Thermal Desorption Spectroscopy 17
3 XPS and HRCLS 21
4 Surface X-ray Diffraction 29
4.1 Introduction to SXRD . . . . . . . . . . . . . . . . . . . . . . . . 29
4.2 Batch Reactor for Harsh Reaction Conditions at ESRF, ID03 . . . 31
5 Auger Electron Spectroscopy 37
6 Reflection Absorption Infrared Spectroscopy RAIRS 43
6.1 Theoretical Survey of RAIR Spectroscopy . . . . . . . . . . . . . 43
6.1.1 IR Reflection Absorption . . . . . . . . . . . . . . . . . . . 43
6.1.2 Single Diatomic Adsorbate . . . . . . . . . . . . . . . . . . 44
6.1.3 Coupling of the Vibrations in Adsorbed CO . . . . . . . . 47
6.2 Measurement of a FT-RAIR Spectrum . . . . . . . . . . . . . . . 47
6.3 The RAIRS Apparatus . . . . . . . . . . . . . . . . . . . . . . . . 50
7 DFT Calculations on Adsorbate Systems 53
7.1 Structural Optimisation and Electronic Energy Calculation . . . . 54
7.2 Adsorption Energies . . . . . . . . . . . . . . . . . . . . . . . . . 56
7.3 Frequency Calculations . . . . . . . . . . . . . . . . . . . . . . . . 56
7.4 Calculation of Surface Core Level Shifts . . . . . . . . . . . . . . 57
7.5 Modelling Chemical Reactions . . . . . . . . . . . . . . . . . . . . 60
56 CONTENTS
7.5.1 Manual Shift of Atoms orAtom Groupsalong a Predefined
Reaction Coordinate . . . . . . . . . . . . . . . . . . . . . 61
7.5.2 Nudged Elastic Band Calculations . . . . . . . . . . . . . . 61
8 Atmospheric Pressure Reaction Measurements 65
8.1 Reactor System . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
8.1.1 Gas Supply and Gas Mixture . . . . . . . . . . . . . . . . 66
8.1.2 Fixed Bed Reactor . . . . . . . . . . . . . . . . . . . . . . 68
8.1.3 Analytics - Quadrupole Mass Spectrometer . . . . . . . . . 68
9 Sample Cleaning and Preparation Procedures 71
9.1 Ru(0001). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
9.2 RuO (110) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 722
9.3 RuO Cl (110) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 772−x x
9.4 Preparation of Chlorinated RuO Catalysts at High Pressures . . 792
II Ruthenium Dioxide(110) as Model Catalyst - Litera-
ture Survey 81
10 The RuO (110) Surface 832
10.1 Oxidation of Ru(0001) . . . . . . . . . . . . . . . . . . . . . . . . 83
10.2 RuO (110) films on Ru(0001) . . . . . . . . . . . . . . . . . . . . 862
11 Chemical Activity of RuO (110) 912
11.1 Adsorption of CO on Reduced RuO (110) . . . . . . . . . . . . . 912
11.2 Adsorption of O on RuO (110) . . . . . . . . . . . . . . . . . . . 942 2
11.3 CO Oxidation on RuO (110) - from UHV to 1 atm . . . . . . . . 952
11.4 HCl Oxidation over RuO . . . . . . . . . . . . . . . . . . . . . . 972
III Chlorination of RuO (110) 1012
12 Chlorination Mechanism of RuO (110) 1032
12.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
12.2 DFT Study: Proposal of a Reaction Mechanism . . . . . . . . . . 104CONTENTS 7
12.3 Chlorination of Hydrogen Pretreated
RuO (110) by HCl . . . . . . . . . . . . . . . . . . . . . . . . . . 1102
12.4 Chlorination of RuO (110) by HCl Exposure . . . . . . . . . . . . 1132
12.5 Chlorination of CO Pre-reduced RuO (110) by Cl . . . . . . . . 1182 2
13 Determination of the Degree of Chlorination 121√ √
13.1 The ( 3× 3)R30°-Cl-Ru(0001) Phase . . . . . . . . . . . . . . 121
13.2 Chlorine Content on RuO Cl (110) . . . . . . . . . . . . . . . . 1242−x x
13.2.1 Determination of the Sum Formula of Chlorinated RuO . 1262
13.3 Summary: Chlorination of RuO (110) . . . . . . . . . . . . . . . . 1262
IV Structural Dynamics of Chlorinated RuO 1292
14 Interaction of CO with RuO Cl (110) 1312−x x
14.1 CO Adsorption on RuO Cl (110) . . . . . . . . . . . . . . . . . 1312−x x
14.1.1 HRCLS Study: CO Adsorption on RuO Cl (110) . . . . 1322−x x
14.1.2 Adsorption of CO on RuO Cl (110) under UHV . . . . . 1342−x x
14.1.3 Influence of Cl on the Vibrational Properties of CO . . 138ot ot
14.1.4 CO + O Coadsorbates . . . . . . . . . . . . . . . . . . 140ot ot
14.2 Mild Reduction of RuO Cl (110) . . . . . . . . . . . . . . . . . 1442−x x
14.2.1 Reduction of RuO Cl (110) by CO in a One-Step Proce-2−x x
dure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
14.2.2 Thermal Desorption of CO from (Cl +CO )/CO onot br br ot
RuO Cl (110). . . . . . . . . . . . . . . . . . . . . . . . 1472−x x
14.3 Chapter Summary . . . . . . . . . . . . . . . . . . . . . . . . . . 150
15 Influence of Oxygen on RuO Cl (110) 1532−x x
15.1 Thermal Stability of RuO Cl (110) . . . . . . . . . . . . . . . . 1532−x x
15.2 The Cl ↔ Cl Shift Reaction . . . . . . . . . . . . . . . . . . . 159br ot
15.2.1 HRCLS Study: O Treatment of RuO Cl (110) . . . . . 1592 2−x x
15.2.2 RAIRS Study: O Treatment of RuO Cl (110) at T =2 2−x x
700 K . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
15.2.3 The Cl ↔ Cl Shift Reaction . . . . . . . . . . . . . . . 164br ot
15.2.4 CO RAIRS Double Feature after Restoration
of RuO Cl (110) in O . . . . . . . . . . . . . . . . . . . 1732−x x 28 CONTENTS
15.3 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178
16 CO Oxidation on RuO Cl (110) - Reactivity 1812−x x
16.1 O Titration by CO - RAIRS Study . . . . . . . . . . . . . . . . 181ot
16.1.1 O Titration on s-RuO (110) . . . . . . . . . . . . . . . . 182ot 2
16.1.2 O Titration on RuO Cl (110) . . . . . . . . . . . . . . 184ot 2−x x
16.2 In situ CO Oxidation - RAIRS Study . . . . . . . . . . . . . . . . 192
16.2.1 CO Oxidation on RuO Cl (110) under HV conditions2−x x
−6(10 mbar) . . . . . . . . . . . . . . . . . . . . . . . . . . 193
16.3 Reactivity and Stability of RuO Cl (110) . . . . . . . . . . . . 1982−x x
16.3.1 Combined Reactivity and Stability Measurements under
Reducing Feed Gas Composition . . . . . . . . . . . . . . 198
16.3.2 Stability against CO in Different Pressure Regimes . . . . 204
16.4 Summary of the Results - CO Oxidation over RuO Cl (110) . . 2072−x x
17 CO Oxidation under Atmospheric Pressure Conditions 209
17.1 CO Oxidation over Fully Oxidised RuO . . . . . . . . . . . . . . 2092
17.2 CO Oxidation over H -Reduced RuO . . . . . . . . . . . . . . . . 2122 2
17.3 CO Oxidation over Chlorinated RuO . . . . . . . . . . . . . . . . 2142
17.4 CO Oxidation over Chlorinated RuO after O Treatment . . . . 2142 2
17.5 CO Oxidation over Chlorinated RuO after Reduction by H . . . 2172 2
17.6 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219
V Conclusions 221
18 Summary and Outlook 223
VI Appendices 229
A Graphical Representations of the RuO (110) Surface 2312
B Lebenslauf 233
C Danksagung 235
D Eidesstattliche Erklärung 237CONTENTS 9
E Zusammenfassung in deutscher Sprache 23910 CONTENTS