AgÃncia Nacional do PetrÃleo / Activated carbons are amorphous materials represented by a pore size distribution (PSD) which usually reproduce the experimental isotherm of N2 at 77 K. Presently, we obtain this distribution using the activated carbon slit-pore model and isotherms calculated by molecular simulation. In this study, we have evaluated the extent to which the use of more realistic activated carbon models influences on the characterization, as well as the possibility of representing the activated carbon by a minimum three-pore PSD. Adsorption isotherms were calculated using the Grand Canonical ensemble within the Monte Carlo method, and compared with experimental isotherms of commercial activated carbons. The deconvolution method with non negative least squares was used to determine the PSDs. We observed that the models containing heterogeneity factors were more accurate than the simplified models, and that activated carbons could be well represented by a minimum three-pore distribution without significant loss of precision. Furthermore, we demonstrated that the minimum PSD could be applied to formulate virtual porous carbon models that are useful in the heterogeneity study. Finally, we propose the use of the minimum PSD to replace the classical calculations of average pore size. / Carbonos ativados sÃo materiais amorfos representados por uma distribuiÃÃo de tamanho de poros (PSD) que usualmente reproduz a isoterma experimental de N2 a 77 K. Presentemente esta distribuiÃÃo à obtida com o uso do modelo de carbono ativado de placas paralelas de grafeno e isotermas calculadas por simulaÃÃo molecular. Neste estudo avaliou-se a influÃncia do uso de modelos de poros de carbono ativado mais realistas sobre a caracterizaÃÃo, bem como a possibilidade de representar o carbono ativado por uma PSD mÃnima constituÃda de apenas trÃs poros. Isotermas de adsorÃÃo foram calculadas utilizando-se o algoritmo de Monte Carlo no ensemble grande canÃnico e comparadas com as isotermas experimentais de carbonos ativados comerciais. O mÃtodo de deconvoluÃÃo com mÃnimos quadrados nÃo negativos foi utilizado para determinaÃÃo das PSDs. Observou-se que modelos contendo fatores de heterogeneidade mostraram-se mais precisos que os modelos simplificados. Notou-se ainda que efetivamente o carbono ativado pode ser representado por uma PSD mÃnima de trÃs poros sem perda significativa de precisÃo. AlÃm disso, demonstrou-se que a distribuiÃÃo mÃnima pode ser usada para elaborar modelos virtuais de carbono que sÃo Ãteis no estudo de heterogeneidades. Finalmente propomos o uso da PSD mÃnima em substituiÃÃo ao cÃlculo clÃssico de tamanho mÃdio de poros.

This cumulative dissertation is a compendium of five peer-reviewed and published scientific papers on developing an advanced NMR Cryoporometry toolbox for pore architecture characterization. The dissertation contains five chapters. The first introduces porous materials, their types and applications. Chapter two describes the fundamentals of fluid phase equilibria in mesoporous solids and how modifications of the well-known Laplace equation describe various fluid phase equilibria. The basic principles of the Gas Sorption and NMR Cryoporometry techniques are discussed. In chapter three, different characterization techniques are amalgamated onto a common framework which can be used to compare fluid phase coexistence in porous materials of different pore sizes. Chapter four explains a completely new NMR Cryoporometry characterization methodology developed for cylindrical and spherical pore shapes. Chapter five concludes and crowns the present work by discussing the complementary benefits of the advanced technique in characterizing random porous materials and accounting for pore connectivity effects. All materials synthesized for the work in this dissertation have been obtained through collaborations with the groups of Profs. Dr. Michael Fröba and Simone Mascotto of the Hamburg University and Prof. Dr. Dirk Enke of the Leipzig University.:Table of Contents Thesis Summary ........................................................................................................1 List of publications ......................................................................................................2 Acknowledgements ...................................................................................................4 CHAPTER 1:.............................................................................................................10 Introduction ..............................................................................................................10 CHAPTER 2:.............................................................................................................12 Fluid Phase Equilibria in Mesoporous Solids ..........................................................12 2.1 Gas Sorption................................................................................................... 13 2.1.1 Adsorption Isotherms................................................................................ 15 2.1.2 Adsorption Hysteresis............................................................................... 18 2.1.3 Scanning Behavior.................................................................................... 23 2.2 NMR Cryoporometry ....................................................................................... 25 2.2.1 Pore Size Distribution (PSD)....................................................................... 28 2.3 Serially-Connected Pore Model (SCPM)......................................................... 29 2.4 Problem Statement ......................................................................................... 30 CHAPTER 3:..............................................................................................................32 Analogy between Characterization Techniques ......................................................32 • Publication 3. On the Comparative Analysis of Different Phase Coexistences in Mesoporous Materials CHAPTER 4:.............................................................................................................42 An Advanced NMR Cryoporometry Approach.........................................................42 • Publication 4.1. Nuclear Magnetic Resonance Cryoporometry Study of Solid−Liquid Equilibria in Interconnected Spherical Nanocages • Publication 4.2. A novel approach for advanced thermoporometry characterization of mesoporous solids: Transition kernels and the serially connected pore model CHAPTER 5:.............................................................................................................65 Characterizing Random Porous Materials................................................................65 • Publication 5.1. Comparative Gas Sorption and Cryoporometry Study of Mesoporous Glass Structure: Application of the Serially Connected Pore Model • Publication 5.2. Impact of Geometrical Disorder on Phase Equilibria of Fluids and Solids Confined in Mesoporous Materials Appendix A:.............................................................................................................100 Porous Solid Characterization Techniques............................................................100 A.1: Mercury Intrusion Porosimetry (MIP) ........................................................... 100 A.1.1. Experimental Set-up.............................................................................. 101 A.2: Gas Sorption................................................................................................ 103 A.2.1. Experimental Set-Up ............................................................................. 103 A.2: NMR Cryoporometry.................................................................................... 106 A.2.2. Experimental Set-Up ............................................................................. 106 Appendix B:..............................................................................................................109 Supporting information ............................................................................................109 Appendix C:.............................................................................................................115 Author contributions ................................................................................................115 Bibliography ............................................................................................................117