CAREER: Fundamental Limits of Physical Adsorption in Porous Materials

University Of Pittsburgh, Pittsburgh PA

Investigators

Abstract

Title: CAREER: Fundamental Limits of Physical Adsorption in Porous Materials 1653375 Wilmer The development of new porous materials is a critical part of improving important gas storage and separations applications. These include the deployment of methane and/or hydrogen gases as alternative fuels, development of new filters for removing trace gaseous contaminants from air, and separation of carbon dioxide from flue gas to mitigate greenhouse emissions from the burning of fossil fuels. In the past decade, the design of novel porous materials on the molecular level has led to an exponential growth in the available structures, with variations in porosity, topology, and surface area all affecting performance of the material in a given application. Computational methods have enabled rapid screening of the available materials for particular conditions, but also highlighted that certain material performance technical targets may not be achievable. In this project, computational methods will be used to probe the limits of material performance for physical adsorption to porous materials at ambient and sub-ambient temperatures. Whereas past computational screening has suggested physical limits of adsorption capacity for one class of materials, i.e., metal organic frameworks (MOFs), this project will explore pseudomaterials, which represent all potential atomistic arrangements of matter in a porous material. The upper bound in performance of pseudomaterials will necessarily represent an upper bound of the real material subset, and thus provide the identification of physical limits of material performance that can be used for engineering design and research prioritization. Classical molecular modeling will be used to compute adsorption capacity and diffusivity, and the Maxwell model will be used to predict the selectivity of mixed-matrix membranes; force field parameters for the pseudomaterials will be systematically and continuously varied to bracket reasonable limits. Optimization procedures will be used to manage the large potential configuration of parameters. The observed upper bounds for material performance will be correlated to material design parameters, such as surface area and pore volume, among others. One graduate student will be trained in this project, which will also include mentoring of high school students and undergraduates from underrepresented minority groups. An educational outreach plan will include development and dissemination of educational movies on the fundamental science of gas adsorption, including those relevant to carbon capture to mitigate climate change.