Adsorption and Diffusion in Porous Systems

Kinetic Monte Carlo Simulation of Statistical Mechanical Models and Coarse-Grained Mesoscale Descriptions of Catalytic Reaction–Diffusion Processes: 1D Nanoporous and 2D Surface Systems

“…Given the importance of transport in these materials for applications to catalysis, separations, and sequestration, there is naturally extensive experimental and theoretical literature on this topic. We refer reader to reviews ,,, and selected recent papers. , There are extensive studies for species like CH 4 , CF 4 , and CCl 4 , with diameters of ∼0.4 nm and above which are often described by a spherical united atom model . Species such as ethane are described by the union of two spherical united atoms .…”

“…We have focused on three classes of catalytic systems where spatial correlations are important but where the origin and nature of the correlations differ: (i) Catalytic conversion reactions in functionalized nanoporous materials with arrays of 1D linear nanopores , − where passing of reactant and product molecules is strongly inhibited. These systems operate in a nonequilibrium spatially heterogeneous steady state with strong concentration variations within the pores.…”

“…In this review, we focus on scenarios where spatial correlations impact reaction–diffusion behavior. For catalysis in 1D nanoporous systems , such as zeolites − and functionalized mesoporous silica, , severe transport limitations , (in the extreme case leading to single-file diffusion) induce strong correlations of kinetic origin that invalidate standard mean-field treatments. − For catalytic reactions on 2D crystalline surfaces in the low-pressure, lower-coverage regime, lateral interactions between reactant species usually induce subtle superlattice ordering or perhaps 2D phase separation. , Associated significant correlations of thermodynamic origin can impact reaction kinetics, , e.g., if reaction occurs predominantly at boundaries between reactant domains . For higher pressures and coverages, inhibited mobility can enhance correlations of kinetic origin as demonstrated for both simple Ziff–Gulari–Barshad (ZGB)-type − and realistic − reaction models.…”

Langevin and Fokker-Planck Analyses of Inhibited Molecular Passing Processes Controlling Transport and Reactivity in Nanoporous Materials

“…Inhibited diffusive transport in nanoporous materials has been analyzed extensively given applications to separations, sequestration, and catalysis [1][2][3][4][5][6][7]. These materials include zeolites with pore diameters from d p ¼ 0.5-2 nm [4], and mesoporous silica nanoparticles (MSN) with d p ≥ 2 nm [8].…”

Catalytic conversion reactions in nanoporous systems with concentration-dependent selectivity: Statistical mechanical modeling

“…Direct molecular or Langevin dynamics simulation [26][27][28] is not viable to describe the overall reactiondiffusion process on the appropriate time scale (i.e., reactants entering, diffusing within, reacting, and products diffusing within and being extruded from the pore, with dynamics generally mediated by the presence of a solvent). Thus, instead spatially discrete coarse-grained stochastic modeling is typically implemented [3][4][5][6][7][8][9][10][11].…”