Zirconium dioxide supported Copper Catalysts for the Methanol Steam Reforming vorgelegt von Diplom-Mineralogin Alexandra Szizybalski aus Potsdam Fakultät II – Mathematik und Naturwissenschaften der Technischen Universität Berlin zur Erlangung des akademischen Grades Doktor der Naturwissenschaften -Dr. rer. nat.- genehmigte Dissertation Promotionsausschuss Vorsitzender: Prof. Dr. rer. nat. P. Hildebrandt Berichter/Gutachter: Prof. Dr. rer. nat. M. Lerch Berichter/Gutachter: Priv.-Doz. Dr. T. Ressler Tag der wissenschaftlichen Aussprache: 25. April 2005 Berlin 2005 I D 83 II Table of Contents Table of Contents .......................................................................................................................... III Zusammenfassung........................................................................................................................VII Abstract ...................................................................................................................................... VIII Danksagung...................................................................................................................................IX 1 Introduction....................................................................................................................... 1 1.1 Motivation and Strategy......................................................................................................... 1 1.2 Hydrogen production from methanol .................................................................................... 6 1.2.1 Comparison of possible reactions in terms of the suitability for fuel cell applications6 1.2.2 Catalysts for the methanol synthesis and steam reforming of methanol...................... 7 1.3 Temperature programmed reduction of CuO/ZrO2 in comparison with bulk CuO and Cu/ZnO ................................................................................................................................ 10 1.4 Relationship between bulk structure and activity of supported copper catalysts ................ 12 1.5 Relationship between surface structure and activity of supported copper catalysts............ 13 1.6 Outline of the work.............................................................................................................. 13 1.7 References............................................................................................................................ 16 2 Materials.......................................................................................................................... 18 2.1 Preparation and characterization of CuO/Zr02..................................................................... 19 2.2 Structural Chemistry............................................................................................................ 22 2.2.1 Copper metal: Cu....................................................................................................... 22 2.2.2 Copper (II) oxide (tenorite): CuO .............................................................................. 23 2.2.3 Copper (I) oxide (cuprite): Cu2O................................................................................ 24 2.2.4 Zirconium dioxide: ZrO2 ............................................................................................ 26 2.3 SEM (Secondary Electron Microscopy).............................................................................. 29 2.4 References............................................................................................................................ 30 3 Experimental and Theoretical Details............................................................................. 31 3.1 X-ray diffraction.................................................................................................................. 32 3.1.1 Theory ........................................................................................................................ 32 3.1.2 Ex- and in situ set-up and instrumentation................................................................. 34 3.2 X-ray absorption spectroscopy (XAS)................................................................................. 36 3.2.1 Theory of EXAFS and XANES ................................................................................. 36 3.2.2 XAS experiments, instrumentation and data processing............................................ 38 3.3 N2O decomposition (refers to Reactive Frontal Chromatography (RFC)) and N2 adsorption (BET) ................................................................................................................................... 42 III 3.3.1 Fundamentals and experiment.................................................................................... 42 3.3.2 Evaluation of the experimental results ....................................................................... 43 3.4 Thermal Analysis (TG and DSC) combined with mass spectrometry................................. 44 3.4.1 Fundamentals and Apparatus ..................................................................................... 44 3.4.2 Experimental details................................................................................................... 45 3.5 Nuclear Magnetic Resonance (NMR).................................................................................. 45 3.5.1 Motivation .................................................................................................................. 45 3.5.2 Fundamentals and Apparatus ..................................................................................... 45 3.5.3 Experimental details................................................................................................... 46 3.6 Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM).... 46 3.6.1 Fundamentals and Apparatus ..................................................................................... 47 3.7 Infrared Spectroscopy (IR).................................................................................................. 48 3.7.1 Fundamentals and Aparatus ....................................................................................... 48 3.8 References............................................................................................................................ 50 4 In situ investigation of structure-activity relationships................................................... 52 4.1 Introduction.......................................................................................................................... 52 4.2 Results.................................................................................................................................. 53 4.2.1 XRD investigation of the precursor and the reduced Cu/ZrO2 catalyst ..................... 53 4.2.2 N2O decomposition .................................................................................................... 54 4.2.3 X-ray absorption spectroscopy................................................................................... 56 4.2.4 Reduction kinetics...................................................................................................... 60 4.2.5 Steam reforming of methanol..................................................................................... 61 4.2.6 High temperature treatment of Cu/ZrO2 in H2 ........................................................... 64 4.2.7 Nuclear magnetic resonance (NMR) spectroscopy.................................................... 65 4.3 Discussion............................................................................................................................ 67 4.3.1 Structure of the CuO/ZrO2 precursor ......................................................................... 68 4.3.2 Reduction of the CuO/ZrO2 precursor........................................................................ 69 4.3.3 Structure of the activated Cu/ZrO2 catalyst................................................................ 69 4.3.4 High temperature treatment of Cu/ZrO2 in H2 ........................................................... 70 4.3.5 Methanol steam reforming on a Cu/ZrO2 catalyst..................................................... 70 4.4 Conclusion ........................................................................................................................... 73 4.5 References............................................................................................................................ 75 5 The influence of preparation on structure and activity ................................................... 76 5.1 Introduction.......................................................................................................................... 76 IV 5.2 Experimental........................................................................................................................ 77 5.2.1 Catalysts ..................................................................................................................... 77 5.2.2 Steam reforming of methanol in a three channel parallel reactor .............................. 77 5.3 Results.................................................................................................................................. 78 5.3.1 Catalysis tests in a three channel parallel reactor....................................................... 78 5.3.2 XRD investigation of the precursors and the