Gennady Gor: Research

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The main focus of the Computational Laboratory for Porous Materials is nanoporous materials, solids with pores of 100 nanometers and below. Such materials play a significant role in both nature and technology. Synthetic nanoporous materials are employed in the chemical industry as adsorbents, catalysts and separation membranes, among other uses. Naturally occurring nanoporous materials include coal and shale, key fuels in the production of energy. Another research focus is soot agglomerates, which are not porous, but rather nanostructured materials with features on the same scale as nanoporous solids. We work on the wide spectrum of phenomena related to the interfaces between these nanoporous or nanostructured solids and fluids: fluids adsorption, fluids transport and the propagation of ultrasound in fluid-saturated porous media, to name a few. Our approaches are mainly theoretical; we use various modeling techniques to represent phenomena at the nanoscale: Monte Carlo simulations, molecular dynamics, density functional theory and finite element analysis. However, in 2022 we added experimental research to our portfolio.

The current projects are:

A brief description of each of the projects is given below.

This recording of a presentation made for undergraduate students in 2020 also gives a short overview of some of the research projects. Another video highlights Jason Ogbebor's undergraduate research experience.

Note for potential graduate and undergraduate researchers: we are always looking for strong candidates to join the group. The list of the possible projects is not limited to the ones above. Interested candidates should email to Dr. Gennady Gor gor@njit.edu with a short cover letter and a CV. Although most of the projects involve collaborations with experimental groups at NJIT and beyond, our research is purely theoretical and computational. Thus strong math skills is a necessary condition to join the group, programming experience is a plus.

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Elastic Properties of Confined Fluids

Compressibility of a fluid in a porous medium determines the response of the medium to mechanical loads, and elastic waves propagation in particular. If the pores of the medium are in the nanometer range, many thermodynamic properties of the fluid confined in such pores are altered, and the fluid compressibility is not an exception. We study the compressibility of simple and complex fluids in confinement using both molecular simulations and experiments relate in order to understand the properties of fluid-saturated nanoporous media (such as hydrocarbons bearing shales).

Schematic of an ultrasonic-adsorption setup, assembled by Jason Ogbebor (collaboration with Prof. Khalizov lab).

Funding: National Science Foundation, New jersey Institute of Technology (Seed Grant)

Publications: Dobrzanski, C. D.; Gurevich, B.; Gor, G. Y. "Elastic Properties of Confined Fluids from Molecular Modeling to Ultrasonic Experiments on Porous Solids" Appl. Phys. Rev. 2021, 8, 021317, DOI: 10.1063/5.0024114
Maximov, M. A.; Gor, G. Y. "Molecular Simulations Shed Light on Potential Uses of Ultrasound in Nitrogen Adsorption Experiments", Langmuir 2018, 34(51), 15650-15657, DOI: 10.1021/acs.langmuir.8b02909.
Dobrzanski, C. D.; Maximov, M. A.; Gor, G. Y. "Effect of Pore Geometry on the Compressibility of a Confined Simple Fluid", J. Chem. Phys., 2018, 148, 054503, DOI: 10.1063/1.5008490, preprint is available at arxiv.org arXiv:1710.05220 [physics.chem-ph]
Gor, G. Y.; Gurevich, B. "Gassmann Theory Applies to Nanoporous Media", Geophys. Res. Lett., 2018, 45(1), 146-155, DOI: 10.1002/2017GL075321, preprint is available at arxiv.org arXiv:1710.05216 [physics.geo-ph]

Researchers: Jason Ogbebor, Satiago Flores Roman Collaborators: Alexei Khalizov (NJIT), Boris Gurevich (Curtin University, Australia), Maxim Lebedev (Curtin University, Australia), John Valenza (Exxonmobil), Peter Ravikovitch (Exxonmobil)

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Morphological Changes of Atmospheric Black Carbon

Soot is a major environmental pollutant with impacts ranging from air quality and human health to climate. The extent of these impacts depends on the microstructure of soot nanoparticles and their surface properties. The soot microstructure is complex, with nanoparticles being fractal aggregates of graphitic spherules mixed with organic and inorganic combustion products or other atmospheric chemicals. On top of it, soot nanoparticles often change structure when interacting with chemicals adsorbed on their surface. The main goal of this project is to develop a molecular-based model for soot nanoparticles restructuring (Gor's group) and verify it against experimental measurements (Khalizov's group).
SEM micrographs of (a) fresh soot particle, (b) soot particle coated with anthracene, where original morphology is sustained, and (c) soot particle coated with phenanthrene, where the fractal particle collapsed into a globule. (From Dr. Alexei Khalizov, unpublished).

Funding: New jersey Institute of Technology (Seed Grant)

Publications: Ivanova, E. V.; Emelianova, A.; Khalizov, A. F.; Gor, G. Y. "Molecular Simulation of Benzene Adsorption in Graphitic and Amorphous Carbon Slit Pores" J. Chem. Eng. Data 2022, 67, 7, 1765-1778, DOI: 10.1021/acs.jced.2c00063
Ivanova, E. V.; Khalizov, A. F.; Gor, G. Y. "Kinetic Model for Competitive Condensation of Vapor between Concave and Convex Surfaces in a Soot Aggregate" Aerosol Sci. Technol. 2021, 55(3), 302-315, DOI: 10.1080/02786826.2020.1846677
Chen, C.; Enekwizu, O. Y.; Fan, X.; Dobrzanski, C. D.; Ivanova, E. V.; Ma, Y.; Gor, G. Y.; Khalizov, A. F. "Single parameter for predicting the morphology of atmospheric black carbon", Environ. Sci. Technol., 2018, 52(24), 14169-14179, DOI: 10.1021/acs.est.8b04201

Researchers: Elly Ivanova Collaborators: Alexei Khalizov (NJIT), Nicole Riemer (UIUC)

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Adsorption-Induced Deformation of Nanoporous Materials

When a solid surface accommodates guest molecules, they induce noticeable stresses to the surface and cause its strain. Nanoporous materials have high surface area and, therefore, are very sensitive to this effect called adsorption-induced deformation. In recent years, there has been significant progress in both experimental and theoretical studies of this phenomenon, driven by the development of new materials as well as advanced experimental and modeling techniques. Also, adsorption-induced deformation has been found to manifest in numerous natural and engineering processes, e.g., drying of concrete, water-actuated movement of non-living plant tissues, change of permeation of zeolite membranes, swelling of coal and shale, etc. Our goal is to develop a quantitative molecular-based model for this phenomenon.

In humid air a pine cone closes, in dry air it opens. These processes are due to the mechanical stresses induced by humidity adsorption and desorption in the porous structure of the pine cone. When a nanoporous material adsorbs fluid, it can both expand or contract. This pine cone is not a real one, but an artificial pine cone made of nanoporous silica (from Van Opdenbosch et al., Adv. Mater. 2016, 28, 5235-5240).

Funding: National Science Foundation

Publications: Yurikov, A.; Lebedev, M.; Gor, G. Y.; Gurevich, B. "Sorption-Induced Deformation and Elastic Weakening of Bentheim Sandstone", J. Geophys. Res. Solid Earth, 2018, 123(10), 8589-8601 DOI: 10.1029/2018JB016003
Balzer, C.; Waag, A. M.; Gehret, S.; Reichenauer, G.; Morak, R.; Ludescher, L.; Paris, O.; Putz, F.; Elsaesser, M.; Husing, N.; Bernstein, N.; Gor, G. Y.; Neimark, A. V. "Adsorption-induced deformation of hierarchically-structured mesoporous silica - effect of local anisotropy", Langmuir, 2017, 33 (22), p. 5592-5602, DOI: 10.1021/acs.langmuir.7b00468
Gor, G. Y.; Huber, P.; Bernstein, N. "Adsorption-Induced Deformation of Nanoporous Materials - a Review", Appl. Phys. Rev., 2017, 4, 011303, DOI: 10.1063/1.4975001

Researchers: Alina Emelianova, Vincent Tews Collaborators: Oskar Paris (Montanuniversity Leoben, Austria), Gudrun Reichenauer (ZAE Bayern, Germany), Patrick Huber (TUHH, Germany)

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Molecular Modeling of Toxic Compounds

In some cases molecular simulations can be used as an alternative to experiments. This is the case in particular when the chemicals of interest are extremely toxic, and experimental measurements are dangerous. Examples include studies of chemical warfare agents, as well as some of the industrial compounds (e.g. isocyanates).

Several organophosphorus compounds, such as G-agents sarin and soman have been synthesized during the World War II to be used as chemical warfare agents (CWA). Despite the 1993 Chemical Weapons Convention, that outlaws the production and use of chemical weapons and their precursors, the use of CWA by terrorists still remain a threat. Thus there is a need to develop processes for chemical protection, capture and decontamination of CWAs. These studies require knowledge of thermodynamic properties of CWAs, in particular quantitative predictions of phase equilibrium of CWA in the presence of adsorbents. Due to the extreme toxicity of CWAs, experiments with them are very limited, and many of the experiments are made with their less toxic simulants. We employ molecular simulations for both CWAs and simulants. Modeling data for simulants can be readily verified experimentally, and justify the use of modeling data for CWAs for predictions as an alternative to experiments.

Read more about Dr. Gor participation in MSEE here and about the grant supporting this research here

TOC figure from our recent publication on sarin and its common simulants.

Funding: MSEE URA Seed Grant (DTRA).

Publications: Emelianova, A.; Gor, G. Y. "Molecular Simulations of Vapor-Liquid Equilibrium of Isocyanates" J. Phys. Chem. B 2021, 125, 45, 12528-12538, DOI: 10.1021/acs.jpcb.1c07132;
Emelianova, A.; Basharova, E.; Kolesnikov, A; Villaseco Arribas, E.; Ivanova, E. V.; Gor, G. Y. "Force Fields for Molecular Modeling of Sarin and its Simulants: DMMP and DIMP" J. Phys. Chem. B 2021, 125, 16, 4086-4098, DOI: 10.1021/acs.jpcb.0c10505

Researchers: Ella Ivanova, Allen Reed, Matthew Stickles, Alina Emelianova Collaborators: Edward Dreizin (NJIT), Mirko Schoenitz (NJIT)

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Modeling of Amino Acids at Mineral Interfaces

We are studying behaviour of various amino acids to better undestand and fine-tune additives to toothpaste. NJIT highlighted this research in a news item, please read "Chemical Engineering Solves Problems with Computer Simulation". A video below also provides an idea about this project.

Funding: Colgate-Palmolive

Researchers: Alina Emelianova Collaborators: Andrei Potanin (Colgate-Palmolive), Tatiana Brinzari (Colgate-Palmolive)

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Materials Properties of Separators in Li-Ion Batteries

Lithium-ion batteries (LIBs) is the leading solution for electrical energy storage, which provide the highest energy and power per unit mass. Although it is already a well-developed technology, it still has one weak point - safety. A lithium-ion battery failure may cause thermal runaway; and the battery can catch on fire. While the performance characteristics of the batteries (e.g. specific power or specific energy) are determined by the electrode materials, the battery safety relies on the separator. LIB separators are typically made of porous semicrystalline polypropylene. Recent experiments showed that, when polypropylene separators are immersed in carbonate solvents used in LIBs, the separators mechanical properties are significantly reduced. The extent of the observed reduction is unexpected, and the physical mechanism is unclear. We aim to elucidate this mechanism on the molecular level to provide a path towards the development of porous polymeric membranes with improved mechanical properties.
Structure of a lithium battery cell (left). Two challenging problems related to the properties of the separator: lithium intercalation into the electrode particles causes noticeable expansion of the anode particles. Expanding anode compresses the separator, decreasing the ion transport through its pores (center). Lithium dendrite can grow through the separator and cause short circuit (right).

Funding: NJIT Seed Grant

Researchers: Marcos Molina Collaborators: Craig Arnold (Princeton University), Andrew Maximov (Cherepovets State University, Russia)

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New Methods for Characterization of Porous Materials

Porous materials have myriad of applications. Nowadays, materials are carefully tailored for each application. Materials scientists and chemist need precise tools for characterization of the synthesized samples, to determine the surface area, pore morphology, pore size distribution, etc. Gas adsorption has been utilized for this purpose. We develop theoretical models of gas adsorption in porous materials, as well as employ new phenomena for characterization purposes (such as ultrasound or adsorption-induced deformation).
Left: SEM Structure of silica colloidal crystals (synthetic opals). Right: Solid-fluid interaction potential for molecular simulation of adsorption in 3DOm carbons.

Publications: Maximov, M. A.; Molina, M.; Gor, G. Y. "The Effect of Interconnections on Gas Adsorption in Materials with Spherical Mesopores: a Monte Carlo Simulation Study" J. Chem. Phys. 2021, 154, 114706 DOI: 10.1063/5.0040763;
Maximov, M. A.; Galukhin, A. V.; Gor, G. Y. "Pore Size Distribution of Silica Colloidal Crystals from Nitrogen Adsorption Isotherms" Langmuir 2019, 35(47), 14975-14982, DOI: 10.1021/acs.langmuir.9b02252;
Galukhin, A. V.; Bolmatenkov, D.; Emelianova, A.; Zharov, I.; Gor, G. Y. "Porous Structure of Silica Colloidal Crystals" Langmuir 2019, 35(6), 2230-2235, DOI: 10.1021/acs.langmuir.8b03476

Researchers: Marcos Molina, Alina Emelianova Collaborators: Andrey Galukhin (Kazan University, Russia), Ilya Zharov (University of Utah)

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