Hydroxyl-Functionalized Polymers of Intrinsic Microporosity and Dual-Functionalized Blends for High-Performance Membrane-Based Gas Separations.

Membrane technology has shown significant growth during the past two decades in the gas separation industry due to its energy-savings, compact and modular design, continuous operation, and environmentally benign nature. Robust materials with higher permeability and selectivity are key to reduce capital and operational cost, pushing it forward to replace or debottleneck conventional energy-intensive unit operations such as distillation. Recently designed ladder polymers of intrinsic microporosity (PIM) and polyimides of intrinsic microporosity (PIM-PI) with pores <20 Å have demonstrated excellent gas permeation performance. Here, a series of plasticization-resistant PIM-based membrane materials is reported, including the first example of a hydroxyl-functionalized triptycene- and Tröger's base-derived ladder PIM and two PIM-PI homopolymers and a series of dual-functionalized polyimide blends containing hydroxyl- and carboxyl-functionalized groups. Specifically, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA)-based PIM-PI blends demonstrated extremely high selectivity for a variety of industrially important applications. An optimized polyimide blend containing ─OH and ─COOH groups showed permselectivity values of 136 for CO2/CH4, 11.4 for O2/N2 and 636 for H2/CH4. Such extreme size-sieving capabilities are attributed to physical crosslinking induced by strong hydrogen bonding forming tightly structured polymer networks. The study provides a new general strategy for developing plasticization resistant, robust, and highly-selective PIM-based membrane materials.

Aggregation Induced Emission-Based Covalent Organic Frameworks for High-Performance Optical Wireless Communication.

Here, we report the first utilization of covalent organic frameworks (COFs) in optical wireless communication (OWC) applications. In the solid form, aggregation-induced emission (AIE) luminogen often shows promising emissive characteristics that augment radiative decays and improve fluorescence. We have synthesized an AIE-COF through the Knoevenagel condensation reaction by taking advantage of the ability to carefully design and alter the COF structure by integrating an AIE luminogen with linear building blocks. The synthesized AIE-COF exhibited a high solid-state photoluminescence quantum yield (∼39%) and a short photoluminescence lifetime (∼1 ns), crucial for achieving modulation bandwidth for high-speed OWC applications. For comparison, we constructed an aggregation-caused quenching based COF, showing a similar lifetime but almost insignificant quantum yield. The orthogonal frequency-division multiplexing modulation strategy employed by the AIE-COF demonstrates remarkable high-rate data transmission, with a wide -3 dB modulation bandwidth of nearly 200 MHz and achieving high net data rates of 825 Mb/s, outperforming traditional materials. These results open new avenues for the ability to design and finetune new COF materials for their utilization as color converters in developing cutting-edge OWC components, enabling faster and more efficient data transfer.

An Ultrastable Aqueous Ammonium-Ion Battery Using a Covalent Organic Framework Anode.

Aqueous ammonium ion batteries have garnered significant research interest due to their safety and sustainability advantages. However, the development of reliable ammonium-based full batteries with consistent electrochemical performance, particularly in terms of cycling stability, remains challenging. A primary issue stems from the lack of suitable anode materials, as the relatively large NH4 + ions can cause structural damage and material dissolution during battery operation. To address this challenge, an Aza-based covalent organic framework (COF) material is introduced as an anode for aqueous ammonium ion batteries. This material exhibits superior ammonium storage capabilities compared to existing anode materials. It operates effectively within a negative potential range of 0.3 to‒1.0 V versus SCE, achieves high capacity even at elevated current densities (≈74 mAh g-1 at 10 A g-1), and demonstrates exceptional stability, retaining a capacity over 20 000 cycles at 1.0 A g-1. Furthermore, by pairing this COF anode with a Prussian blue cathode, an ammonium rocking-chair full battery is developedd that maintains 89% capacity over 20 000 cycles at 1.0 A g-1, surpassing all previously reported ammonium ion full batteries. This study offers insights for the design of future anodes for ammonium ion batteries and holds promise for high-energy storage solutions.

p/n-Type Polyimide Covalent Organic Frameworks for High-Performance Cathodes in Sodium-Ion Batteries.

Covalent organic frameworks (COFs) are viewed as promising organic electrode materials for metal-ion batteries due to their structural diversity and tailoring capabilities. In this work, firstly using the monomers N,N,N',N'-tetrakis(4-aminophenyl)-1,4-phenylenediamine (TPDA) and terephthaldehyde (TA), p-type phenylenediamine-based imine-linked TPDA-TA-COF is synthesized. To construct a bipolar redox-active, porous and highly crystalline polyimide-linked COF, i.e., TPDA-NDI-COF, n-type 1,4,5,8-naphthalene tetracarboxylic dianhydride (NDA) molecules are incorporated into p-type TPDA-TA-COF structure via postsynthetic linker exchange method. This tailored COF demonstrated a wide potential window (1.03.6 V vs Na+/Na) with dual redox-active centers, positioning it as a favorable cathode material for sodium-ion batteries (SIBs). Owing to the inheritance of multiple redox functionalities, TPDA-NDI-COF can deliver a specific capacity of 67 mAh g-1 at 0.05 A g-1, which is double the capacity of TPDA-TA-COF (28 mAh g-1). The incorporation of carbon nanotube (CNT) into the TPDA-NDI-COF matrix resulted in an enhancement of specific capacity to 120 mAh g-1 at 0.02 A g-1. TPDA-NDI-50%CNT demonstrated robust cyclic stability and retained a capacity of 92 mAh g-1 even after 10 000 cycles at 1.0 A g-1. Furthermore, the COF cathode exhibited an average discharge voltage of 2.1 V, surpassing the performance of most reported COF as a host material.

Synthesis and crystallization of a carboxylate functionalized N-heterocyclic carbene-based Au13 cluster with strong photo-luminescence.

Here we report the synthesis and crystallization of a -COOH-capped N-heterocyclic carbene (NHC)-protected Au13 cluster. The single-crystal structure of the -COOH-capped NHC-Au13 cluster reveals a classic icosahedral core with one Au atom in its center. The icosahedral core is surrounded by five NHC ligands with pseudo C5 symmetry and exposed carboxyls in a pentagonal antiprism fashion. The detailed formula of the Au cluster was identified as Au13(bi-NHC carboxyl)5Cl2 (hereafter abbreviated as Au13-c). The density functional theory (DFT) calculations confirm that Au13-c is an electronically stable eight-electron super-atom cluster and elucidate its optical transitions in the UV-Vis range. The Au13-c cluster exhibits excellent thermal and chemical stability under bio-relevant conditions. Additionally, this cluster shows a strong red emission in DMF and H2O with an excellent quantum yield (QY) of 40% and 12.6%, respectively. The high QY of Au13-c enables its use in cell imaging on both cancer and noncancerous cells.

Tuning MOF/polymer interfacial pore geometry in mixed matrix membrane for upgrading CO2 separation performance.

The current paradigm considers the control of the MOF/polymer interface mostly for achieving a good compatibility between the two components to ensure the fabrication of continuous mixed-matrix metal-organic framework (MMMOF) membranes. Here, we unravel that the interfacial pore shape nanostructure plays a key role for an optimum molecular transport. The prototypical ultrasmall pore AlFFIVE-1-Ni MOF was assembled with the polymer PIM-1 to design a composite with gradually expanding pore from the MOF entrance to the MOF/polymer interfacial region. Concentration gradient-driven molecular dynamics simulations demonstrated that this pore nanostructuring enables an optimum guided path for the gas molecules at the MOF/polymer interface that decisively leads to an acceleration of the molecular transport all along the MMMOF membrane. This numerical prediction resulted in the successful fabrication of a [001]-oriented nanosheets AlFFIVE-1-Ni/PIM-1 MMMOF membrane exhibiting an excellent CO2 permeability, better than many MMMs, and ideally associated with a sufficiently high CO2/CH4 selectivity that makes this membrane very promising for natural gas/biogas purification.

Porous Organic Polymers for Efficient and Selective SO2 Capture from CO2-rich Flue Gas.

The quest for effective technologies to reduce SO2 pollution is crucial due to its adverse effects on the environment and human health. Markedly, removing a ppm level of SO2 from CO2-containing waste gas is a persistent challenge, and current technologies suffer from low SO2/CO2 selectivity and energy-intensive regeneration processes. Here using the molecular building blocks approach and theoretical calculation, we constructed two porous organic polymers (POPs) encompassing pocket-like structures with exposed imidazole groups, promoting preferential interactions with SO2 from CO2-containing streams. Markedly, the evaluated POPs offer outstanding SO2/CO2 selectivity, high SO2 capacity, and an easy regeneration process, making it one of the best materials for SO2 capture. To gain better structural insights into the notable SO2 selectivity of the POPs, we used dynamic nuclear polarization NMR spectroscopy (DNP) and molecular modelling to probe the interactions between SO2 and POP adsorbents. The newly developed materials are poised to offer an energy-efficient and environment-friendly SO2 separation process while we are obliged to use fossil fuels for our energy needs.

Bimetallic Metal Sites in Metal-Organic Frameworks Facilitate the Production of 1-Butene from Electrosynthesized Ethylene.

Converting CO2 to synthetic hydrocarbon fuels is of increasing interest. In light of progress in electrified CO2 to ethylene, we explored routes to dimerize to 1-butene, an olefin that can serve as a building block to ethylene longer-chain alkanes. With goal of selective and active dimerization, we investigate a series of metal-organic frameworks having bimetallic catalytic sites. We find that the tunable pore structure enables optimization of selectivity and that periodic pore channels enhance activity. In a tandem system for the conversion of CO2 to 1-C4H8, wherein the outlet cathodic gas from a CO2-to-C2H4 electrolyzer is fed directly (via a dehumidification stage) into the C2H4 dimerizer, we study the highest-performing MOF found herein: M' = Ru and M″ = Ni in the bimetallic two-dimensional M'2(OAc)4M″(CN)4 MOF. We report a 1-C4H8 production rate of 1.3 mol gcat-1 h-1 and a C2H4 conversion of 97%. From these experimental data, we project an estimated cradle-to-gate carbon intensity of -2.1 kg-CO2e/kg-1-C4H8 when CO2 is supplied from direct air capture and when the required energy is supplied by electricity having the carbon intensity of wind.

Planar Core and Macrocyclic Shell Stabilized Atomically Precise Copper Nanocluster Catalyst for Efficient Hydroboration of C-C Multiple Bond.

Atomically precise metal nanoclusters (NCs) have become an important class of catalysts due to their catalytic activity, high surface area, and tailored active sites. However, the design and development of bond-forming reaction catalysts based on copper NCs are still in their early stages. Herein, we report the synthesis of an atomically precise copper nanocluster with a planar core and unique shell, [Cu45(TBBT)29(TPP)4(C4H11N)2H14]2+ (Cu45) (TBBT: 4-tert-butylbenzenethiol; TPP: triphenylphosphine), in high yield via a one-pot reduction method. The resulting structurally well-defined Cu45 is a highly efficient catalyst for the hydroboration reaction of alkynes and alkenes. Mechanistic studies show that a single-electron oxidation of the in situ-formed ate complex enables the hydroboration via the formation of boryl-centered radicals under mild conditions. This work demonstrates the promise of tailored copper nanoclusters as catalysts for C-B heteroatom bond-forming reactions. The catalysts are compatible with a wide range of alkynes and alkenes and functional groups for producing hydroborated products.

Translocation and Confinement of Tetraamines in Adaptable Microporous Cavities.

Metal-Organic Frameworks can be grafted with amines by coordination to metal vacancies to create amine-appended solid adsorbents, which are being considered as an alternative to using aqueous amine solutions for CO2 capture. In this study, we propose an alternative mechanism that does not rely on the use of neutral metal vacancies as binding sites but is enabled by the structural adaptability of heterobimetallic Ti2Ca2 clusters. The combination of hard (Ti4+) and soft (Ca2+) metal centers in the inorganic nodes of the framework enables MUV-10 to adapt its pore windows to the presence of triethylenetetramine molecules. This dynamic cluster response facilitates the translocation and binding of tetraamine inside the microporous cavities to enable the formation of bis-coordinate adducts that are stable in water. The extension of this grafting concept from MUV-10 to larger cavities not restrictive to CO2 diffusion will complement other strategies available for the design of molecular sorbents for decarbonization applications.

Machine learning potential for modelling H2 adsorption/diffusion in MOFs with open metal sites.

Metal-organic frameworks (MOFs) incorporating open metal sites (OMS) have been identified as promising sorbents for many societally relevant-adsorption applications including CO2 capture, natural gas purification and H2 storage. This has been ascribed to strong specific interactions between OMS and the guest molecules that enable the MOF to achieve an effective capture even under low gas pressure conditions. In particular, the presence of OMS in MOFs was demonstrated to substantially boost the H2 binding energy for achieving high adsorbed hydrogen densities and large usable hydrogen capacities. So far, there is a critical bottleneck to computationally attain a full understanding of the thermodynamics and dynamics of H2 in this sub-class of MOFs since the generic classical force fields (FFs) are known to fail to accurately describe the interactions between OMS and any guest molecules, in particular H2. This clearly hampers the computational-assisted identification of MOFs containing OMS for a target adsorption-related application since the standard high-throughput screening approach based on these generic FFs is not applicable. Therefore, there is a need to derive novel FFs to achieve accurate and effective evaluation of MOFs for H2 adsorption. On this path, as a proof-of-concept, the soc-MOF-1d containing OMS, previously envisaged as a potential platform for H2 adsorption, was selected as a benchmark material and a machine learning potential (MLP) was derived for the Al-soc-MOF-1d from a dataset initially generated by ab initio molecular dynamics (AIMD) simulations. This MLP was further implemented in MD simulations to explore the H2 binding modes as well as the temperature dependence distribution of H2 in the MOF pores from 10 K to 80 K. MLP-Grand Canonical Monte Carlo (GCMC) simulations were then performed to predict the H2 sorption isotherm of Al-soc-MOF-1d at 77 K that was further confirmed using sorption data we collected on this sample. As a further step, MLP-based molecular dynamics (MD) simulations were conducted to anticipate the kinetics of H2 in this MOF. This work delivers the first MLP able to describe accurately the interactions between the challenging H2 guest molecule and MOFs containing OMS. This innovative strategy applied to one of the most complex molecules owing to its highly polarizable nature, paves the way towards a more systematic accurate and efficient in silico assessment of MOFs containing OMS for H2 adsorption and beyond to the low-pressure capture of diverse molecules.

Advancing Membrane Technology: Ordered Macroporous ZIF-67 as a Filler in Mixed Matrix Membranes for Enhanced Propylene/Propane Separation.

Conventional separation technologies for valuable commodities require substantial energy, accounting for 10%-15% of global consumption. Mixed-matrix membranes (MMMs) offer a promising solution by combining processable polymers with selective inorganic fillers. Here, the potential of using ordered microporous structured materials is demonstrated as MMM fillers. The use of ordered macroporous ZIF-67 in combination with the well-known 6FDA-DAM polymer leads to superior performance in the important separation of propylene from propane. The enhanced performance can be rationalized with the help of advanced microscopy, which demonstrates that the polymer is able to penetrate the macroporous network around which the MOF (Metal-Organic Framework) is synthesized, resulting in a much better interphase between the two components and the homogeneous distribution of the filler, even at high loadings.

Multiple neighboring active sites of an atomically precise copper nanocluster catalyst for efficient bond-forming reactions.

Atomically precise copper nanoclusters (NCs) are an emerging class of nanomaterials for catalysis. Their versatile core-shell architecture opens the possibility of tailoring their catalytically active sites. Here, we introduce a core-shell copper nanocluster (CuNC), [Cu29(StBu)13Cl5(PPh3)4H10]tBuSO3 (StBu: tert-butylthiol; PPh3: triphenylphosphine), Cu29NC, with multiple accessible active sites on its shell. We show that this nanocluster is a versatile catalyst for C-heteroatom bond formation (C-O, C-N, and C-S) with several advantages over previous Cu systems. When supported, the cluster can also be reused as a heterogeneous catalyst without losing its efficiency, making it a hybrid homogeneous and heterogeneous catalyst. We elucidated the atomic-level mechanism of the catalysis using density functional theory (DFT) calculations based on the single crystal structure. We found that the cooperative action of multiple neighboring active sites is essential for the catalyst's efficiency. The calculations also revealed that oxidative addition is the rate-limiting step that is facilitated by the neighboring active sites of the Cu29NC, which highlights a unique advantage of nanoclusters over traditional copper catalysts. Our results demonstrate the potential of nanoclusters for enabling the rational atomically precise design and investigation of multi-site catalysts.

Copper nanoparticles encapsulated in zeolitic imidazolate framework-8 as a stable and selective CO2 hydrogenation catalyst.

Metal-organic frameworks have drawn attention as potential catalysts owing to their unique tunable surface chemistry and accessibility. However, their application in thermal catalysis has been limited because of their instability under harsh temperatures and pressures, such as the hydrogenation of CO2 to methanol. Herein, we use a controlled two-step method to synthesize finely dispersed Cu on a zeolitic imidazolate framework-8 (ZIF-8). This catalyst suffers a series of transformations during the CO2 hydrogenation to methanol, leading to ~14 nm Cu nanoparticles encapsulated on the Zn-based MOF that are highly active (2-fold higher methanol productivity than the commercial Cu-Zn-Al catalyst), very selective (>90%), and remarkably stable for over 150 h. In situ spectroscopy, density functional theory calculations, and kinetic results reveal the preferential adsorption sites, the preferential reaction pathways, and the reverse water gas shift reaction suppression over this catalyst. The developed material is robust, easy to synthesize, and active for CO2 utilization.

Design of Mixed-Matrix MOF Membranes with Asymmetric Filler Density and Intrinsic MOF/Polymer Compatibility for Enhanced Molecular Sieving.

The separation of high-value-added chemicals from organic solvents is important for many industries. Membrane-based nanofiltration offers a more energy-efficient separation than the conventional thermal processes. Conceivably, mixed-matrix membranes (MMMs), encompassing metal-organic frameworks (MOFs) as fillers, are poised to promote selective separation via molecular sieving, synergistically combining polymers flexibility and fine-tuned porosity of MOFs. Nevertheless, conventional direct mixing of MOFs with polymer solutions results in underutilization of the MOF fillers owing to their uniform cross-sectional distribution. Therefore, in this work, a multizoning technique is proposed to produce MMMs with an asymmetric-filler density, in which the MOF fillers are distributed only on the surface of the membrane, and a seamless interface at the nanoscale. The design strategy demonstrates five times higher MOF surface coverage, which results in a solvent permeance five times higher than that of conventional MMMs while maintaining high selectivity. Practically, MOFs are paired with polymers of similar chemical nature to enhance their adhesion without the need for surface modification. The approach offers permanently accessible MOF porosity, which translates to effective molecular sieving, as exemplified by the polybenzimidazole and Zr-BI-fcu-MOF system. The findings pave the way for the development of composite materials with a seamless interface.

Rare Earth alb-MOFs: From Synthesis to Their Deployment for Amine-Sensing Application in Aqueous Media.

The pursuit of developing sensors, characterized by their fluorescence-intensity enhancement or "turn-on" behavior, for accurately detecting noxious small molecules, such as amines, at minimal levels remains a significant challenge. Metal-organic frameworks (MOFs) have emerged as promising candidates as sensors as a result of their diverse structural features and tunable properties. This study introduces the rational synthesis of a new highly coordinated (6,12)-connected rare earth (RE) alb-MOF-3, by combining the nonanuclear 12-connected hexagonal prismatic building units, [RE9(µ3-O)2(µ3-X)12(OH)2(H2O)7(O2C-)12], with the 6-connected rigid trigonal prismatic extended triptycene ligand. The resulting Y-alb-MOF-3 material is distinguished by its high microporosity and Brunauer-Emmett-Teller surface area of approximately 1282 m2/g, which offers notable hydrolytic stability. Remarkably, it demonstrates selective detection capabilities for primary aliphatic amines in aqueous media, as evidenced by fluorescence turn-on behavior and photoluminescence (PL) titration measurements. This work emphasizes the potential of MOFs as sensors in advancing their selectivity and sensitivity toward various analytes.

How Reproducible is the Synthesis of Zr-Porphyrin Metal-Organic Frameworks? An Interlaboratory Study.

Metal-organic frameworks (MOFs) are a rapidly growing class of materials that offer great promise in various applications. However, the synthesis remains challenging: for example, a range of crystal structures can often be accessed from the same building blocks, which complicates the phase selectivity. Likewise, the high sensitivity to slight changes in synthesis conditions may cause reproducibility issues. This is crucial, as it hampers the research and commercialization of affected MOFs. Here, it presents the first-ever interlaboratory study of the synthetic reproducibility of two Zr-porphyrin MOFs, PCN-222 and PCN-224, to investigate the scope of this problem. For PCN-222, only one sample out of ten was phase pure and of the correct symmetry, while for PCN-224, three are phase pure, although none of these show the spatial linker order characteristic of PCN-224. Instead, these samples resemble dPCN-224 (disordered PCN-224), which has recently been reported. The variability in thermal behavior, defect content, and surface area of the synthesised samples are also studied. The results have important ramifications for field of metal-organic frameworks and their crystallization, by highlighting the synthetic challenges associated with a multi-variable synthesis space and flat energy landscapes characteristic of MOFs.

Charge Transfer Process of a Solvated Hydrogen-Bonded Organic Network.

We show the first example of an organic linker (OL) terminated by carboxylic groups that can form a hydrogen-bonded network/polymer (HBN) in solution under controlled conditions in which the photogenerated charges can hop from a monomer OL to the hydrogen-bonded backbone of OLs, as probed by transient absorption (fs-TA). While fs-TA reveals a slow twisting process in the monomer form of the OL, the formation of a hydrogen-bonded network in solution suppresses such process and favors instead a charge transfer (CT) state along the low-lying hydrogen-bonded backbone. Theoretical calculations show that such solvated HBN in a specific polar solvent is stabilized due to the huge change of the dipole moment from monomer compared to the network, leading to a charge delocalization character due to the symmetry breaking. Our findings will open new avenues for implementing solvated hydrogen-bonded molecules in applications such as sensing and photocatalysis.

Fluorine-Boosted Kinetic and Selective Molecular Sieving of C6 Derivatives.

Porous molecular sorbents have excellent selectivity towards hydrocarbon separation with energy saving techniques. However, to realize commercialization, molecular sieving processes should be faster and more efficient compared to extended frameworks. In this work, we show that utilizing fluorine to improve the hydrophobic profile of leaning pillararenes affords a substantial kinetic selective adsorption of benzene over cyclohexane (20 : 1 for benzene). The crystal structure shows a porous macrocycle that acts as a perfect match for benzene in both the intrinsic and extrinsic cavities with strong interactions in the solid state. The fluorinated leaning pillararene surpasses all reported organic molecular sieves and is comparable to the extended metal-organic frameworks that were previously employed for this separation such as UIO-66. Most importantly, this sieving system outperformed the well-known zeolitic imidazolate frameworks under low pressure, which opens the door to new generations of molecular sieves that can compete with extended frameworks for more sustainable hydrocarbon separation.

A promising sensing platform for explosive markers: Zeolite-like metal-organic framework based monolithic composite as a case study.

Preconcentration for on-site detection or subsequent determination is a promising technique for selective sensing explosive markers at low concentrations. Here, we report divinylbenzene monolithic polymer in its blank form (neat-DVB) and as a composite incorporated with sodalite topology zeolite-like metal-organic frameworks (3-ZMOF@DVB), as a sensitive, selective, and cost-effective porous preconcentrator for aliphatic nitroalkanes in the vapor phase as explosive markers at infinite dilution. The developed materials were fabricated as 18 cm gas chromatography (GC) monolithic capillary columns to study their separation performance of nitroalkane mixture and the subsequent physicochemical study of adsorption using the inverse gas chromatography (IGC) technique. A strong preconcentration effect was indicated by a specific retention volume adsorption/desorption ratio equal to 3 for nitromethane on the neat-DVB monolith host-guest interaction, and a 14% higher ratio was observed using the 3-ZMOF@DVB monolithic composite despite the low percentage of 0.7 wt.% of sod-ZMOF added. Furthermore, Incorporating ZMOF resulted in a higher percentage of micropores, increasing the degree of freedom more than bringing stronger adsorption and entropic-driven interaction more than enthalpic. The specific free energy of adsorption (ΔGS) values increased for polar probes and nitroalkanes, denoting that adding ZMOFs earned the DVB monolithic matrix a more specific character. Afterward, Lewis acid-base properties were calculated, estimating the electron acceptor (KA) and electron donor (KB) constants. The neat-DVB was found to have a Lewis basic character with KB/KA = 7.71, and the 3-ZMOF@DVB had a less Lewis basic character with KB/KA = 3.82. An increased electron-accepting nature can be directly related to incorporating sod-ZMOF into the DVB monolithic matrix. This work considers the initial step in presenting a portable explosives detector or preconcentrating explosive markers trace prior to more sophisticated analysis. Additionally, the IGC technique allows for understanding the factors that led to the superior adsorption of nitroalkanes for the developed materials.