Chemistry and Dynamics of Supercritical Carbon Dioxide and Methane in the Slit Pores of Layered Silicates.

ConspectusIn the mid 2010s, high-pressure diffraction and spectroscopic tools opened a window into the molecular-scale behavior of fluids under the conditions of many CO sequestration and shale/tight gas reservoirs, conditions where CO and CH are present as variably wet supercritical fluids. Integrating high-pressure spectroscopy and diffraction with molecular modeling has revealed much about the ways that supercritical CO and CH behave in reservoir components, particularly in the slit-shaped micro- and mesopores of layered silicates (phyllosilicates) abundant in caprocks and shales. This Account summarizes how supercritical CO and CH behave in the slit pores of swelling phyllosilicates as functions of the HO activity, framework structural features, and charge-balancing cation properties at 90 bar and 323 K, conditions similar to a reservoir at ∼1 km depth.

Non-Equilibrium Modeling of Concentration-Driven processes with Constant Chemical Potential Molecular Dynamics Simulations.

ConspectusConcentration-driven processes in solution, i.e., phenomena that are sustained by persistent concentration gradients, such as crystallization and surface adsorption, are fundamental chemical processes.

Biohybrid Membrane Formation by Directed Insertion of Aquaporin into a Solid-State Nanopore.

Biohybrid nanopores combine the durability of solid-state nanopores with the precise structure and function of biological nanopores. Particular care must be taken to control how biological nanopores adapt to their surroundings once they come into contact with the solid-state nanopores. Two major challenges are to precisely control this adaptability under dynamic conditions and provide predesigned functionalities that can be manipulated for engineering applications.

Tuning the Transport Properties of Gases in Porous Graphene Membranes with Controlled Pore Size and Thickness.

Porous graphene membranes have emerged as promising alternatives for gas-separation applications due to their atomic thickness enabling ultrahigh permeance, but they suffer from low gas selectivity. Whereas decreasing the pore size below 3 nm is expected to increase the gas selectivity due to molecular sieving, it is rather challenging to generate a large number of uniform small pores on the graphene surface. Here, a pore-narrowing approach via gold deposition onto porous graphene surface is introduced to tune the pore size and thickness of the membrane to achieve a large number of small pores.