De plasma-geassisteerde synthese van heterogene metallo-silicaat katalysatoren

Heterogeneous catalysts are usually synthesized by a series of multiple unit operations. Some of these unit operations require high temperatures and environmentally harmful solvents and thus demand lots of energy, labor, and also time. Plasma enhanced chemical vapor deposition proves to be a very interesting synthesis procedure for heterogeneous catalysts, because it avoids the use of solvents and uses the electrical energy instead of the thermal energy to create a chemically active environment in which the synthesis of the heterogeneous catalysts can take place. However, the use of a plasma for the synthesis of catalysts is not very common. It is only recently emerging as an innovative alternative for the classical synthesis procedures. In this work, a non-equilibrium, or cold, plasma is employed for the synthesis of powders for use as catalysts in biomass related reactions. The fact that the synthesis procedure only requires one step is not the only innovative characteristic; another ingenious property of the procedure is the use of homemade atomizers which makes it possible to tune the introduction of nanosized precursor droplets into the plasma zone, with no restriction of the vapor pressure, which is often the case with other methods. First, the reactor setup itself was refined and optimized so that it was possible to create powders in a safe and reproducible way. Then, the reactor parameters (plasma power, total gas flow, and electrical frequency) were optimized towards powders synthesis to ensure that all resources were used efficiently. Additionally, optimization towards the catalytic properties of the produced materials was carried out as well. The studied reaction for the optimization was the isomerization of glucose into fructose, which is an intermediate step in the conversion of biomass into fuels and chemicals. It was found that the innovative way of producing heterogeneous catalysts proved to be successful. High conversions, selectivities and thus yields have been reached. The catalyst properties are comparable to what can be found in literature, however, it is the simple nature of the synthesis procedure that proves to be a great advantage when it is compared to more conventional synthesis pathways.TABLE OF CONTENTS iv LIST OF PUBLICATIONS vii ABSTRACT viii SAMENVATTING ix SCOPE OF THE THESIS xi LIST OF ABBREVIATIONS xii CHAPTER I: STATE OF THE ART 1 I.0. Supportive information 2 I.1. Abstract 3 I.2. Introduction 4 I.3. Catalyst synthesis 6 I.4. Catalyst treatment 16 I.5. Summary 23 I.6. Acknowledgements 24 I.7. Reference list 25 CHAPTER II: PLASMA TECHNOLOGY 31 II.0. Supportive information 32 II.1. Plasma generation 33 II.2. Reactor design 39 II.3. Reference list 51 CHAPTER III: Sn-SILICATE CATALYSTS 53 III.0. Supportive information 54 III.1. Abstract 60 III.2. Introduction 61 III.3. Experimental 63 III.4. Results and Discussion 67 III.5. Conclusion 82 III.6. Acknowledgements 83 III.7. Reference list 84 CHAPTER IV: HYBRID METAL SILICATES 87 IV.0. Supportive information 88 IV.1. Abstract 90 IV.2. Introduction 91 IV.3. Materials and methods 93 IV.4. Results and discussion 99 IV.5. Conclusion 108 IV.6. Acknowledgements 109 IV.7. Reference list 110 CHAPTER V: HETEROGENEOUS BASES 113 V.0. Supportive information 114 V.1. Introduction 115 V.2. Experimental 117 V.3. Results and discussion 121 V.4. Conclusion 131 V.5. Reference list 133 CHAPTER VI: FUTURE PERSPECTIVES 135 VI.1. Reactor 136 VI.2. Catalyst stability 138 VI.3. Conclusion 139nrpages: 139status: publishe