A data-science approach to predict the heat capacity of nanoporous materials.

The heat capacity of a material is a fundamental property of great practical importance. For example, in a carbon capture process, the heat required to regenerate a solid sorbent is directly related to the heat capacity of the material. However, for most materials suitable for carbon capture applications, the heat capacity is not known, and thus the standard procedure is to assume the same value for all materials. In this work, we developed a machine learning approach, trained on density functional theory simulations, to accurately predict the heat capacity of these materials, that is, zeolites, metal-organic frameworks and covalent-organic frameworks. The accuracy of our prediction is confirmed with experimental data. Finally, for a temperature swing adsorption process that captures carbon from the flue gas of a coal-fired power plant, we show that for some materials, the heat requirement is reduced by as much as a factor of two using the correct heat capacity.

Toward Optimal Photocatalytic Hydrogen Generation from Water Using Pyrene-Based Metal-Organic Frameworks.

Metal-organic frameworks (MOFs) are promising materials for the photocatalytic H2 evolution reaction (HER) from water. To find the optimal MOF for a photocatalytic HER, one has to consider many different factors. For example, studies have emphasized the importance of light absorption capability, optical band gap, and band alignment. However, most of these studies have been carried out on very different materials. In this work, we present a combined experimental and computation study of the photocatalytic HER performance of a set of isostructural pyrene-based MOFs (M-TBAPy, where M = Sc, Al, Ti, and In). We systematically studied the effects of changing the metal in the node on the different factors that contribute to the HER rate (e.g., optical properties, the band structure, and water adsorption). In addition, for Sc-TBAPy, we also studied the effect of changes in the crystal morphology on the photocatalytic HER rate. We used this understanding to improve the photocatalytic HER efficiency of Sc-TBAPy, to exceed the one reported for Ti-TBAPy, in the presence of a co-catalyst.

Multiscale Modeling Strategy of 2D Covalent Organic Frameworks Confined at an Air-Water Interface.

Two-dimensional covalent organic frameworks (2D COFs) have attracted attention as versatile active materials in many applications. Recent advances have demonstrated the synthesis of monolayer 2D COF via an air-water interface. However, the interfacial 2D polymerization mechanism has been elusive. In this work, we have used a multiscale modeling strategy to study dimethylmethylene-bridged triphenylamine building blocks confined at the air-water interface to form a 2D COF via Schiff-base reaction. A synergy between the computational investigations and experiments allowed the synthesis of a 2D-COF with one of the linkers considered. Our simulations complement the experimental characterization and show the preference of the building blocks to be at the interface with a favorable orientation for the polymerization. The air-water interface is shown to be a key factor to stabilize a flat conformation when a dimer molecule is considered. The structural and electronic properties of the monolayer COFs based on the two monomers are calculated and show a semiconducting nature with direct bandgaps. Our strategy provides a first step toward the in silico polymerization of 2D COFs at air-water interfaces capturing the initial steps of the synthesis up to the prediction of electronic properties of the 2D material.

Pyrene-based metal organic frameworks: from synthesis to applications.

Pyrene is one of the most widely investigated aromatic hydrocarbons given to its unique optical and electronic properties. Hence, pyrene-based ligands have been attractive for the synthesis of metal-organic frameworks (MOFs) in the last few years. In this review, we will focus on the most important characteristics of pyrene, in addition to the development and synthesis of pyrene-based molecules as bridging ligands to be used in MOF structures. We will summarize the synthesis attempts, as well as the post-synthetic modifications of pyrene-based MOFs by the incorporation of metals or ligands in the structure. The discussion of promising results of such MOFs in several applications; including luminescence, photocatalysis, adsorption and separation, heterogeneous catalysis, electrochemical applications and bio-medical applications will be highlighted. Finally, some insights and future prospects will be given based on the studies discussed in the review. This review will pave the way for the researchers in the field for the design and development of novel pyrene-based structures and their utilization for different applications.

TRPV1 channel as a target for cancer therapy using CNT-based drug delivery systems.

Carbon nanotubes are being considered for the design of drug delivery systems (DDSs) due to their capacity to internalize molecules and control their release. However, for cellular uptake of drugs, this approach requires an active translocation pathway or a channel to transport the drug into the cell. To address this issue, it is suggested to use TRPV1 ion channels as a potential target for drug release by nano-DDSs since these channels are overexpressed in cancer cells and allow the permeation of large cationic molecules. Considering these facts, this work presents three studies using molecular dynamics simulations of a human TRPV1 (hTRPV1) channel built here. The purpose of these simulations is to study the interaction between a single-wall carbon nanotube (SWCNT) and hTRPV1, and the diffusion of doxorubicin (DOX) across hTRPV1 and across a POPC lipid membrane. The first study shows an attractive potential between the SWCNT surface and hTRPV1, tilting the adsorbed SWCNT. The second study shows low diffusion probability of DOX across the open hTRPV1 due to a high free energy barrier. Although, the potential energy between DOX and hTRPV1 reveals an attractive interaction while DOX is inside hTRPV1. These results suggest that if the channel is dilated, then DOX diffusion could occur. The third study shows a lower free energy barrier for DOX across the lipid membrane than for DOX across hTRPV1. Taking into account the results obtained, it is feasible to design novel nano-DDSs based on SWCNTs to accomplish controlled drug release into cells using as translocation pathway, the hTRPV1 ion channel.