La lecture à portée de main
Description
Informations
Publié par | universitat_potsdam |
Publié le | 01 janvier 2009 |
Nombre de lectures | 39 |
Langue | Deutsch |
Poids de l'ouvrage | 19 Mo |
Extrait
Max‐Planck Institut für Kolloid‐ und Grenzflächenforschung
Abteilung Kolloidchemie
Über neue Allotrope und Nanostrukturen von Karbonitriden
On new allotropes and nanostructures of carbon nitrides
Dissertation
zur Erlangung des akademischen Grades
"doctor rerum naturalium"
(Dr. rer. nat.)
in der Wissenschaftsdisziplin "Physikalische Chemie"
eingereicht an der
Mathematisch‐Naturwissenschaftlichen Fakultät
der Universität Potsdam
von
Michael Janus Bojdys
aus Grudziądz, Polen
Potsdam, den 05 Januar 2009 This work is licensed under a Creative Commons License:
Attribution - Noncommercial - Share Alike 3.0 Germany
To view a copy of this license visit
http://creativecommons.org/licenses/by-nc-sa/3.0/de/deed.en
Published online at the
Institutional Repository of the University of Potsdam:
URL http://opus.kobv.de/ubp/volltexte/2010/4123/
URN urn:nbn:de:kobv:517-opus-41236
http://nbn-resolving.org/urn:nbn:de:kobv:517-opus-41236 3
Contents
1 Introduction and motivation.............................................................................................. 6
2 Theoretical background ................................................................................................... 10
2.1 X‐ray diffraction ......................................................................................................... 10
2.1.1 Laue, Ewald, Miller and Bragg relationships ...................................................... 11
2.2 Principles of powder diffraction ................................................................................ 13
2.3 Structure refinement using powder diffraction data ................................................ 15
2.3.1 The method of least squares ............................................................................. 15
2.3.2 Application of least squares refinement to structures ...................................... 16
2.4 Inelastic scattering of electrons and compositional analysis .................................... 19
2.5 Electron diffraction and imaging ............................................................................... 22
2.6 Some thoughts on the interaction of x‐rays and electrons with light solid‐state
materials .............................................................................................................................. 23
3 Graphitic carbon nitride ................................................................................................... 25
3.1 Introduction to carbon nitride materials .................................................................. 25
3.2 Basic considerations on the synthetic pathway to graphitic carbon nitride ............ 27
3.3 Formulation of a condensation pathway 31
3.4 Synthesis of graphitic carbon nitride and its intermediates in LiCl/KCl .................... 34
3.5 Characterisation of graphitic carbon nitride ............................................................. 34
4 A new phase of graphitic carbon nitride – g‐C N ‐mod2, analogous to rhombohedral 3 4
graphite .................................................................................................................................... 45
4.1 A toolbox of solvent systems for ionothermal synthesis .......................................... 45
4.2 Synthesis and characterisation of the graphitic carbon nitride, g‐C N ‐mod2 ......... 46 3 4
5 Graphite chemistry with g‐C N – reductive intercalation .............................................. 56 3 4
5.1 Synthesis and characterisation of K(C N ) – a potassium intercalation compound of 6 8 3
g‐C N .... 57 3 4
6 Heptazine‐based frameworks .......................................................................................... 68
6.1 Introduction to rationally designed frameworks ...................................................... 68
6.2 Synthesis of the triazine precursor materials ........................................................... 71
6.3 From ArCNTz to HBF‐1 – ionothermal synthesis and characterisation .................... 72
6.4 From BiPhCNTz to HBF‐2 – ionothermal and characterisation ................. 83
7 Conclusion and outlook ................................................................................................... 91
8 Appendix .......................................................................................................................... 96
8.1 General methods and characterisation techniques .................................................. 96
8.1.1 Wide angle x‐ray scattering (WAXS) .................................................................. 96
8.1.2 Thermogravimetric analysis (TGA) ..................................................................... 96
8.1.3 Elemental microanalysis .................................................................................... 96
8.1.4 Infrared measurements ..................................................................................... 96
8.1.5 Electron microscopy ........................................................................................... 97
8.1.6 Electron spectroscopy ........................................................................................ 97
8.2 Synthesis of graphitic carbon nitride – g‐C N .......................................................... 97 3 4
8.2.1 Thermogravimetric Analysis. ............................................................................. 98
8.2.2 Results from structureless LeBail fit and unit cell refinement. ......................... 99
8.2.3 Scanning Electron Microscopy Imaging (SEM) of g‐C3N4. .............................. 101
8.3 Synthesis of ArCNTz ................................................................................................. 102
8.4 of BiPhCNTz ............................................................................................. 103 4
8.5 Synthesis of NaphthaCNTz ...................................................................................... 105
8.6 Synthetic challenges ................................................................................................ 108
8.6.1 Bisubstition ...................................................................................................... 108
8.6.2 Hydrolysis of the nitrile group ......................................................................... 108
8.7 Atomic coordinates of HBF‐1 in cif‐fileformat ........................................................ 109
8.8 Indexed and refined unit cell