Efficient and Selective Electrochemical CO to Formic Acid Conversion: A First-Principles Study of Single-Atom and Dual-Atom Catalysts on Tin Disulfide Monolayers.

Electrochemical CO reduction reaction (CORR) is a sustainable approach to recycle CO and address climate issues but needs selective catalysts that operate at low electrode potentials. Single-atom catalysts (SACs) and dual-atom catalysts (DACs) have become increasingly popular due to their versatility, unique properties, and outstanding performances in electrocatalytic reactions. In this study, we used Density Functional Theory along with the computational hydrogen electrode methodology to study the stability and activity of SACs and DACs by adsorbing metal atoms onto SnS monolayers.

Democratizing the Assessment of Thermal Robustness of Metal-Organic Frameworks.

With the pressing need of having reliable materials for carbon dioxide capture, metal-organic frameworks (MOFs) have shown promising performance due to their flexible sign and tunable functionality by applying reticular chemistry principles. One of the main characteristics of practical MOFs is to design thermally robust candidates for sustainable functionality. Here, we introduce a comprehensive methodology for examining the thermal stability of MOFs by combining theoretical calculations and affordable experimental methods to fully describe their performance under thermal variations.

A Dynamic Chemical Clip in Supramolecular Framework for Sorting Alkylaromatic Isomers using Thermodynamic and Kinetic Preferences.

Adsorptive chemical separation is at the forefront of future technologies, for use in chemical and petrochemical industries. In this process, a porous adsorbent selectively allows a single component from a mixture of three or more chemical components to be adsorbed or permeate. To separate the unsorted chemicals, a different adsorbent is needed.

Fluorocarbon-Functionalized Superhydrophobic Metal-Organic Framework: Enhanced CO Uptake via Photoinduced Postsynthetic Modification.

The design and synthesis of porous materials for selective capture of CO in the presence of water vapor is of paramount importance in the context of practical separation of CO from the flue gas stream. Here, we report the synthesis and structural characterization of a photoresponsive fluorinated MOF {[Cd(bpee)(hfbba)]·EtOH} () constructed by using 4,4'-(hexafluoroisopropylidene)bis(benzoic acid) (hfbba), Cd(NO), and 1,2-bis(4-pyridyl)ethylene (bpee) as building units. Due to the presence of the fluoroalkyl -CF functionality, compound exhibits superhydrophobicity, which is validated by both water vapor adsorption and contact angle measurements (152°).

High-throughput screening of metal-organic frameworks for kinetic separation of propane and propene.

We apply molecular simulations to screen a database of reported metal-organic framework structures from the computation-ready, experimental (CoRE) MOF database to identify materials potentially capable of separating propane and propene by diffusion. We report a screening workflow that uses descriptor analysis, conventional molecular dynamics (MD), and Nudged Elastic Band (NEB) energy barrier calculations at both classical force field and Density Functional Theory (DFT) levels. For the first time, the effects of framework flexibility on guest transport properties were fully considered in a screening process and led to the identification of candidate MOFs.

First-Principles Characterization and Experimental Validation of the Solid-Solid Interface in a Novel Organosulfur Cathode for the Li-S Battery.

Organosulfur silanes grafted on an aluminum current collector have been proposed and demonstrated to function as a sulfur source in the cathode for a lithium-sulfur (Li-S) battery. Bis[3-(triethoxysilyl)propyl]disulfide silane (TESPD) and bis[3-(triethoxysilyl)propyl]tetrasulfide silane (TESPT) are typical examples of organosulfur complexes used for the study. These organosulfur silanes act as an insulator.

Equation of State of Fluid Methane from First Principles with Machine Learning Potentials.

The predictive simulation of molecular liquids requires potential energy surface (PES) models that are not only accurate but also computationally efficient enough to handle the large systems and long time scales required for reliable prediction of macroscopic properties. We present a new approach to the systematic approximation of the first-principles PES of molecular liquids using the GAP (Gaussian Approximation Potential) framework. The approach allows us to create potentials at several different levels of accuracy in reproducing the true PES and thus to determine the level of quantum chemistry that is necessary to accurately predict macroscopic properties.

Understanding of the Graphene Oxide/Metal-Organic Framework Interface at the Atomistic Scale.

An atomistic model of the metal-organic framework (MOF) ZIF-8/graphene oxide (GO) interface has been constructed using a combination of density functional theory calculations and force-field-based molecular dynamics simulations. Two microscopic models of GO were constructed integrating basal plane and both basal and edge plane functional groups, called GO-OH and GO-COH, respectively. Analysis of the MOF/GO site-to-site interactions, surface coverage, and GO conformation/stiffness and a full characterization of the interfacial region is provided with a special emphasis on the influence of the chemical composition of GO.

Separation/purification of ethylene from an acetylene/ethylene mixture in a pillared-layer porous metal-organic framework.

Here we report the synthesis, structure and porous properties of a 3D pillared-layer porous framework of Mn(ii)-Mn(iii), {[Mn(bipy)(HO)][Mn(CN)]·2(bipy)·4HO} (1). The guest-removed framework (1a) shows significant uptake of CH, whereas it excludes the other two C2 hydrocarbons (CH and CH). Furthermore, excellent separation proficiency for CH from a mixture of CH and CH (1 : 99, v/v) is realized in a breakthrough column experiment under ambient conditions.

Styrene Purification by Guest-Induced Restructuring of Pillar[6]arene.

The separation of styrene (St) and ethylbenzene (EB) mixtures is important in the chemical industry. Here, we explore the St and EB adsorption selectivity of two pillar-shaped macrocyclic pillar[n]arenes (EtP5 and EtP6; n = 5 and 6). Both crystalline and amorphous EtP6 can capture St from a St-EB mixture with remarkably high selectivity.

Crystal Dynamics in Multi-stimuli-Responsive Entangled Metal-Organic Frameworks.

An understanding of solid-state crystal dynamics or flexibility in metal-organic frameworks (MOFs) showing multiple structural changes is highly demanding for the design of materials with potential applications in sensing and recognition. However, entangled MOFs showing such flexible behavior pose a great challenge in terms of extracting information on their dynamics because of their poor single-crystallinity. In this article, detailed experimental studies on a twofold entangled MOF (f-MOF-1) are reported, which unveil its structural response toward external stimuli such as temperature, pressure, and guest molecules.

Host-Guest [2+2] Cycloaddition Reaction: Postsynthetic Modulation of CO2 Selectivity and Magnetic Properties in a Bimodal Metal-Organic Framework.

Simultaneous tuning of permanent porosity and modulation of magnetic properties by postsynthetic modification (PSM) with light in a metal-organic framework is unprecedented. With the aim of achieving such a photoresponsive porous magnetic material, a 3D photoresponsive biporous framework, MOF1, which has 2D channels occupied by the guest 1,2-bis(4-pyridyl)ethylene (bpee), H2 O, and EtOH molecules, has been synthesized. The guest bpee in 1 is aligned parallel to pillared bpee with a distance of 3.

Dynamic Entangled Porous Framework for Hydrocarbon (C2-C3) Storage, CO2 Capture, and Separation.

Storage and separation of small (C1-C3) hydrocarbons are of great significance as these are alternative energy resources and also can be used as raw materials for many industrially important materials. Selective capture of greenhouse gas, CO2 from CH4 is important to improve the quality of natural gas. Among the available porous materials, MOFs with permanent porosity are the most suitable to serve these purposes.

Structure-Property Relationships in Amorphous Microporous Polymers.

Structural models and physical properties of several amorphous microporous polymers (AMPs) have been investigated using molecular dynamics simulations in an all-atom framework. The modeled structures of AMPs are quantitatively consistent with experimental observations. A linear relationship between the accessible surface area (ASA) and mass density of AMPs has been established.

Amide functionalized microporous organic polymer (Am-MOP) for selective CO₂ sorption and catalysis.

We report the design and synthesis of an amide functionalized microporous organic polymer (Am-MOP) prepared from trimesic acid and p-phenylenediamine using thionyl chloride as a reagent. Polar amide (-CONH-) functional groups act as a linking unit between the node and spacer and constitute the pore wall of the continuous polymeric network. The strong covalent bonds between the building blocks (trimesic acid and p-phenylenediamine) through amide bond linkages provide high thermal and chemical stability to Am-MOP.

Effect of pillar modules and their stoichiometry in 3D porous frameworks of Zn(II) with [Fe(CN)6]3-: high CO2/N2 and CO2/CH4 selectivity.

We report the synthesis, single-crystal structural characterization, and selective gas adsorption properties of three new 3D metal-organic frameworks of Zn(II), {[Zn3(bipy)3(H2O)2][Fe(CN)6]2·2(bipy)·3H2O}n (1), {[Zn3(bipy)][Fe(CN)6]2·(C2H5OH)·H2O}n (2), and {[Zn3(azpy)2(H2O)2][Fe(CN)6]2·4H2O}n (3) (bipy = 4,4'-bipyridyl and azpy = 4,4'-azobipyridyl), bridged by [Fe(CN)6](3-) and exobidentate pyridyl-based linkers. Compounds 1-3 have been successfully isolated by varying the organic linkers (bipy and azpy) and their ratios during the synthesis at RT. Frameworks 1 and 3 feature a biporous-type network.