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Design of Porous Boron Nitride Materials for Applications in Adsorption

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Design of Porous Boron Nitride Materials for Applications in Adsorption Design of Porous Boron Nitride Materials for Applications in Adsorption by Sofia Marchesini A Thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy and the Diploma of Imperial College London Chemical Engineering Department Imperial College London September 2018 Abstract Porous boron nitride (BN) recently emerged as a new class of adsorbent material with bond polarity and unprecedented high thermal and oxidative stabilities. These properties make BN an attractive adsorbent for use in a wide range of adsorption applications, especially those operating under extreme conditions. Yet, the number of studies on this fascinating material remain limited and its structure and chemistry still vastly unknown. A full understanding of its formation mechanisms, as well as control of its pore structure and chemistry, are necessary to exploit its full potential. This thesis presents an in-depth investigation of the effects of synthesis conditions on the formation of porous BN and a detailed characterisation of the material. A novel synthesis method was developed for producing high surface area (>1900 m2/g) porous BN with tuneable micro- and mesoporosity, without the use of templates, presenting opportunity for scalability. The shaping of porous BN powders into industrially relevant pellet morphologies was achieved with no significant detriment to the desirable textural properties of the material. A way to reduce the hydrolytic instability of porous BN is elucidated and samples with significantly higher water tolerance were produced. Finally, porous BN materials with various pore structures and chemistries were tested for a range of adsorption applications in gas, liquid and vapour phase, identifying adsorption mechanisms and outlining potential ways to improve adsorption performance. Overall, this thesis opens the door to the design and improvement of porous BN, establishing it as a promising adsorbent material. 2 Publications and Patent S Marchesini -free synthesis of highly porous ACS Nano, 11 (2017): 10003 10011 RT Woodward, A Jobbe-Duval, S Marchesini, DB Anthony, C Petit, A Bismarck; "Hypercrosslinked polyHIPEs as precursors to designable, hierarchically porous carbon foams" Polymer 115 (2017): 146-53 S Marchesini, A Regoutz, D Payne, C Petit; formation and its Microporous and Mesoporous Materials 243 (2017): 154-163 Patent: Porous Boron nitride, PCT Application No. PCT/GB2018/050686, filed: 16/05/2018 In preparation or submission: S Marchesini, R Shankar, Enhancing the hydrolytic stability of porous boron nitride via the control of crystallinity, porosity and chemical composition Currently being reviewed by industrial partners S Marchesini, aterials with tuneable chemistries , In preparation 3 I hereby declare that this work is my own and that any published work was appropriately referenced. 4 The copyright of this thesis rests with the author. Unless otherwise indicated, its contents are licensed under a Creative Commons Attribution-Non Commercial 4.0 International Licence (CC BY-NC). Under this licence, you may copy and redistribute the material in any medium or format. You may also create and distribute modified versions of the work. This is on the condition that: you credit the author and do not use it, or any derivative works, for a commercial purpose. When reusing or sharing this work, ensure you make the licence terms clear to others by naming the licence and linking to the licence text. Where a work has been adapted, you should indicate that the work has been changed and describe those changes. Please seek permission from the copyright holder for uses of this work that are not included in this licence or permitted under UK Copyright Law. 5 Acknowledgements I would like to express my deepest appreciation to my supervisor, Dr. Camille Petit, for all her help and supervision throughout these four years. Camille always provided prompt, extensive and constructive feedback, allowing me to develop my communication and research skills. She also encouraged me to participate in several national and international conferences and to apply for external funding, which allowed me to learn a lot and present my work to experts in my field. Camille also gave me the opportunity to supervise many undergraduate students, to design their experiments and train them, which taught me a lot. I would like to thank all the students for their help in the lab and all the time spent together! I would also like to thank my industrial supervisor, Dr. Leslie Bolton from BP and my second supervisor, Dr. Matthew Blunt from University College London. They both provided invaluable feedback and technical suggestions and were always extremely supportive. I would like to acknowledge the funding and technical support from BP through the BP International Centre for Advanced Materials (BP-ICAM), which made this research possible. BP also allowed me to spend 3 weeks in Hull, hosting me at the Saltend Chemical Park, where I tested some of the materials previously produced for different applications. I would like to thank everyone who helped me with the experiments while I was there. I would also like to acknowledge EPSRC for the funding through the CDT in Advanced Characterisation of Materials (CDT-ACM), which gave me the opportunity to participate in many courses for professional and personal development. I would like to express my gratitude to the CDT-ACM directors, Dr. Neil Curson and Prof. Stephen Skinner, for their technical and pastoral support. I would also like to acknowledge Dr. Catriona McGilvery, Josh Bailey, Ravi Shankar, Dr. Anna Regoutz and Angus Crake for their help in collecting and analysing results, some of which resulted in peer-reviewed publications. Some special thanks go to all my friends who supported me throughout these four years, the members of the Petit group, the CDT-ACM group and the other friends from Imperial (thank you Moon group). A special thanks to Rob, who made my PhD experience a lot easier. 6 Finally, grazie alla mia famiglia; thanks to my family who was extremely supportive and always present, although from another country. This achievement would not have been possible without your encouragement and immense support. 7 Abbreviations BN Boron Nitride BET Brunauer-Emmett-Teller 1/2/3-D One/Two/Three-dimensional MOFs Metal Organic Frameworks COFs Covalent Organic Frameworks MOPs Microporous Organic Polymers h-BN Hexagonal Boron Nitride r-BN Rhombohedral Boron Nitride c-BN Cubic Boron Nitride w-BN Wurtzite Boron Nitride t-BN Turbostratic Boron Nitride a-BN Amorphous Boron Nitride BNNSs Boron Nitride Nanosheets DMF N,N-Dimethylformamide NMP N-Methyl-2-Pyrrolidone IPA Isopropanol CVD Chemical Vapour Deposition AB Ammonia Borane MAB Tri(methylamino)borazine CTAB Cetyl-Trimethylammonium Bromide P123 Poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) DTAC D-trimethyl ammonium chloride BCN Boron Carbon Nitride SEM Scanning Electron Microscopy SE Secondary Electrons BE Backscattered Electrons XRD X-Ray Diffraction TEM Transmission Electron Microscopy 8 FFT Fast Fourier Transform STEM Scanning Transmission Electron Microscopy BF Bright Field DF Dark Field DFT Density Functional Theory EDX Energy dispersive X-ray spectroscopy WDX Wavelength Dispersive X-ray spectroscopy HAADF High Angle Annular Dark Field ATR Attenuated Total Reflectance XPS X-ray Photoelectron Spectroscopy FTIR Fast Fourier Transform TGA Thermo Gravimetric Analysis MS Mass Spectroscopy RhB Rhodamine B MO Methyl Orange 9 Table of Contents Abstract ...................................................................................................................................... 2 Publications and Patent .............................................................................................................. 3 Acknowledgements .................................................................................................................... 6 Abbreviations ............................................................................................................................. 8 Table of Contents ..................................................................................................................... 10 List of Figures .......................................................................................................................... 15 List of Tables ........................................................................................................................... 21 Thesis Outline .......................................................................................................................... 22 Motivation ............................................................................................................................ 22 Thesis Content ..................................................................................................................... 23 Literature Review............................................................................................... 24 1.1 Adsorption theory ...................................................................................................... 24 1.2 Adsorbent materials................................................................................................... 25 1.3 Boron nitride ............................................................................................................. 27 1.4 Synthesis methods leading to high surface area BN materials.................................. 30 1.5 Top-down
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