Ni-based catalysts for methane dry reforming

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Table of contents

Acknowledgements
General Introduction
CHAPTER I : Literature review
I.1 Methane dry reforming: general context
I.1.1 Methane resources
I.1.2 Pathways for methane-to-syngas conversion
I.1.3 Advantages of dry reforming of methane
I.1.4 Main and side reactions during dry reforming of methane
I.2 Methane dry reforming catalysts: general overview
I.2.1 High performance of noble metals
I.2.2 Use of transition metals and importance of nickel
I.2.3 Existing industrial processes
I.3 Ni-based catalysts for methane dry reforming
I.3.1 Structural approaches to limit nickel sintering and coke resistance
I.3.2 Chemical approaches to enhance carbon resistance
I.4 Aim of this work
I.5 References
CHAPTER II : Experimental part
II.1 Materials preparation
II.1.1 Supports
a) SBA-15 silica supports syntheses
b) Mesoporous CeO2 support synthesis
c) Commercial supports
II.1.2 Addition of metal salts
a) Two solvents impregnation (2S)
b) Incipient wetness impregnation (IWI)
c) Direct synthesis (DS)
II.2 Characterization techniques
II.2.1 N2 adsorption-desorption isotherms
II.2.2 Scanning electron microscopy (SEM)
II.2.3 Transmission electron microscopy (TEM)
II.2.4 X-ray diffraction (XRD)
II.2.5 Temperature-programmed reduction (TPR)
II.2.6 Thermogravimetric analysis coupled to mass spectrometry (TGA-MS)
II.2.7 Raman spectroscopy
II.2.8 Temperature programmed hydrogenation (TPH)
II.2.9 X-ray photoelectron spectroscopy (XPS)
II.3 Catalytic test
II.3.1 General description of the equipment
II.3.2 Operating procedure
II.3.3 Effluent gas analysis
II.3.4 Expression of results
II.3.5 Validation and reproducibility of the test
II.4 Thermodynamics of the reaction
II.4.1 Effect of dilution
II.4.2 Effect of carbon deposition
II.4.3 Effect of pressure
II.5 References
CHAPTER III : Active and stable Ni/SBA-15 catalysts at 500°C
III.1 Material preparation
III.2 Physico-chemical properties of supports and calcined samples
III.2.1. Textural properties of the SBA-151 and SBA-152 supports
III.2.2. Porosity of the calcined impregnated samples
III.2.3. Identification and size of supported nanoparticles
III.2.4. Location of the supported nanoparticles
III.2.5. Reducibility of calcined samples
III.3 Catalytic performance in dry reforming of methane
III.3.1 Catalytic activity
III.3.2 Catalytic stability and selectivity
III.4 Physico-chemical properties of spent catalysts
III.5 Conclusion
III.6 References
CHAPTER IV: Influence of textural properties
IV.1 Comparison of small and larger SBA-15 syntheses
IV.2 Comparison between synthesized SBA-A3 and commercial supports
IV.2.1 Porosity of calcined samples
IV.2.2 Size, dispersion and reducibility of supported nanoparticles
IV.2.3 Catalytic activity and stability
IV.3 Improvement of the synthesized SBA-15 support
IV.3.1 Physico-chemical properties of the samples
IV.3.2 Catalytic activity and stability
IV.3.3 Effect of hydrothermal treatment
IV.4 Conclusion
IV.5 References
CHAPTER V: Influence of preparation procedure
V.1 Effect of nickel addition method
V.1.1 Catalytic activity and stability
V.1.2 Porosity of calcined samples
V.1.3 Reducibility of the samples
V.1.4 Size and dispersion of the supported nanoparticles
V.2 Effect of nickel precursor and pre-treatment
V.2.1 Catalytic activity and stability
V.2.2 Porosity of calcined samples
V.2.3 Reducibility of the samples
V.2.4 Size and dispersion of the supported nanoparticles
V.3 Effect promoters/dopants
V.3.1 Catalytic activity and stability
V.3.2 Porosity of calcined samples
V.3.3 Reducibility of the samples
V.3.4 Structural ordering of reduced and spent catalysts
V.3.5 Size and dispersion of supported nanoparticles
V.4 Influence of the nature of support – preliminary results
V.4.1 Catalytic activity and stability
V.4.2 Porosity of calcined samples
V.4.3 Reducibility of the samples
V.4.4 Identification and size of the supported nanoparticles
V.5 Conclusion
V.6 References
CHAPTER VI : Carbon analysis and supplementary data
VI.1 Carbon analysis on spent catalysts
VI.1.1 Effect of stability test duration
VI.1.2 Carbon quantification on spent catalysts
VI.1.3 Carbon structure on spent catalysts
VI.2 Study of more severe reaction conditions
VI.2.1 Effect of gas hourly space velocity (GHSV)
VI.2.2 Effect of pressure
VI.2.3 Effect of regeneration
VI.3 Conclusion
VI.4 References
Conclusion and perspectives