(2ii) Materials for CO2 Capture, Conversion and Storage

Molecular Dynamics simulations, Density Functional Theory, Interatomic Potential Development, Machine Learning, Free Energy Calculations

Teaching Interests

Chemical Engineering Thermodynamics, Transport Phenomena, Numerical Methods in Chemical Engineering, Unit Operations in Chemical Engineering

Abstract

The severe repercussions of climate change and global warming have garnered attention towards reducing the concentration of CO₂ level in the atmosphere. The emergence of research hotspots, challenges and technologies for carbon capture and storage led to the development and discovery of several materials in the recent past. Materials with adequate CO₂ sorption kinetics can be divided into three main classes namely geological sequestration, metal oxide adsorption and amine solvent absorption. We apply state of the art computational tools such as molecular dynamics (MD), density functional theory (DFT) and machine learning (ML) to study material interactions for CO₂ capture and storage. For geological sequestration we consider smectite clays and limestone-based minerals which are present in abundance in the subsurface of earth. We consider pyrophyllite, beidellite, montmorillonite and gibbsite as layered minerals for CO₂ intercalation and conversion in the interlayers. We study the phenomena using reactive (ReaxFF) and non-reactive (CLAYFF) force field molecular simulations and free energy calculations. The physical properties of CO₂-water medium are being predicted using ML models. Enhanced weathering of limestone-based minerals such as wollastonite and forsterite are being studied using free energy calculations and reactive MD simulations to understand the leaching process at the surface and reactions in the bulk to trap CO₂ in the form of carbonate and bicarbonate precipitates. CO₂ adsorption on metal oxide includes materials such as Gallium oxide, Indium oxide and Gallium-Indium oxide-based alloys. We study CO₂ hydrogenation on the surface of these materials which reduce it to valuable fuels essential for feedstocks. In this study, we perform DFT and ab-initio MD to study the hydrogenation process. Another set of oxides we consider are calcium and magnesium oxide for CO₂ looping. We find the adsorption profile of CO₂ on these metal clusters using free energy calculations and reactive MD simulations. Finally, we study the chemical absorption of CO₂ in amine blends which show faster reactions, higher absorption capacity and lower regeneration energy compared to primary and secondary amines. We elucidate the behavior of different amine blends using reactive MD simulations.

Acknowledgement

Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.