Self-Assembled MOF-on-MOF Nanofabrics for Synergistic Detoxification of Chemical Warfare Agent Simulants

Zr-MOF-Derived Zirconium Oxide Nanozyme and Its Hydrogel Composite Membrane for Organophosphate Detoxification

Organophosphorus nerve agents are among the most hazardous chemical warfare agents, posing serious risks to human health. Developing efficient catalysts and composite materials for their detoxification remains a significant challenge. In this study, we present the first example of zirconium oxide (ZrOx) nanozyme derived from a zirconium-based metal-organic framework (Zr-MOF), which exhibits outstanding catalytic activity for the hydrolysis of a nerve agent simulant, dimethyl-4-nitrophenyl phosphate (DMNP). Moreover, ZrOx was incorporated into a poly(vinyl alcohol) (PVA) matrix with 1,4-diazabicyclo[2.2.2]octane (dabco) as a base, forming a hydrogel composite membrane, named ZrOx@PD. Notably, ZrOx@PD demonstrates superior catalytic efficiency for the solid-phase hydrolysis of DMNP under ambient conditions, outperforming many previously reported catalytic materials and highlighting its potential as a protective material against nerve agents.

Mechanically Robust Mesoporous UiO-66-NH2/Nanofibrous Aerogel for Organophosphonates Detoxification

There is a critical need for novel composite materials for high-performance chemical filtration and detoxification of organophosphonates (OPs) and other harmful compounds found in nerve agents, pesticides, and industrial processes. In this work, rapid hydrolysis of OPs using high-surface-area zirconium-based MOF-aerogel composites is demonstrated. Using a unique surfactant-templated solvothermal synthesis method, mesoporous UiO-66-NH2 grown on the fibers within a polyacrylonitrile (PAN)/polyvinylpyrrolidone (PVP) nanofibrous sponge can produce a 3D MOF-polymer matrix with a specific surface area of up to 900 m2 g-1 comp-almost 2X larger than the highest previously reported values while maintaining robust mechanical integrity. The mesoporous MOF promotes efficient diffusion, and the aerogel matrix provides a high-surface-area platform for spill containment. Unlike activated carbon, which adsorb OPs without degradation, the UiO-66-NH2-sponges hydrolyze OPs upon water contact, significantly reducing their toxicity. The MOF-aerogel sponges withstand stresses up to 40 kPa under 70% strain are shown while maintaining exceptional catalytic efficiency, achieving a methyl paraoxon degradation half-life of 3 min, compared to 15 min for similar microporous MOFs. This innovation accentuates the potential of mesoporous Zr-MOF aerogels for advanced protection, filtration, and catalysis.

Advancing Metal-Organic Framework-Based Composites for Effective Chemical Warfare Agent Detoxification under Real-World Conditions

Threats from toxic chemical warfare agents (CWAs) persist due to war and terrorist attacks, endangering both human beings and the environment. Metal-organic frameworks (MOFs), which feature ordered pore structures and excellent tunability at both metal/metal cluster nodes and organic linkers, are regarded as the best candidates to directly remove CWAs and their simulants via both physical adsorption and chemically catalyzed hydrolysis or oxidization. MOFs have attracted significant attention in the last two decades that has resulted from the rapid development of MOF-based materials in both fundamental research and real-world applications. In this review, the authors focus on the recent advancements in designing and constructing functional MOF-based materials toward CWAs detoxification and discuss how to bridge the gap between fundamental science and real-world applications. With detailed summaries from different points of view, this review provides insights into design rules for developing next-generation MOF-based materials for protection from both organophosphorus and organosulfur CWAs to mitigate potential threats from CWAs used in wars and terrorism attacks.

Intermolecular Forces-Oriented Growth of MOF-on-MOF Heterostructures

Well-controlled conjugation of distinct metal-organic frameworks (MOFs) with dissimilar components and structures into a multi-component MOF system is important for the design of myriad materials with structural complexity, integrated properties, and desired applications. Herein, we developed an interesting integration strategy that relies on intermolecular force, and which can overcome the difference in lattice parameters. The strategy uses the pre-formed MOF matrixes as seeds to direct the self-assembly of secondary MOF particles for the construction of hybrid MOFs. As a proof of concept, the representative core-satellite-type Ni-MOF@ZIF-8 and core-shell-type MOF-74@ZIF-8 heterostructures were achieved. Theory calculations elucidate the uncommon formation of well-defined hybrid MOFs by self-assembly of secondary ZIF-8 particles to anchor on Ni-MOF or MOF-74 seed surface via hydrogen bonds and van der Waals interactions. We anticipate that this work opens an avenue to design the multi-component MOF systems from different MOFs with lattice mismatching.

Synergistic effect of Lewis acid-base sites in Zr4+-doped layered double hydroxides promotes rapid decontamination of nerve and blister agents under ambient conditions

Nerve and blister agents are among the deadliest chemicals posing a major threat to the society, and the development of materials that can rapidly decontaminate them under solvent-free ambient conditions is a major societal challenge. In this paper, layered double hydroxides (ZnAlxZr1-x-LDH) with varying Zr4+ doping content were synthesized and the decontamination properties of nerve and blister agents were investigated under ambient conditions. The results show that, compared to ZnAl-LDH, the ZnAl0.4Zr0.6-LDH with the highest amount of Zr4+ dopant reduced the decontamination reaction half-life of sarin (GB) and soman (GD) by 10 and 9 times, respectively. Mechanism studies revealed that ZnAl0.4Zr0.6-LDH employs the synergistic effect of Lewis acid-base sites to catalyze the decomposition of GB and GD into hydrolysis products and surface-bound hydrolysis products. The study also showed that under ambient conditions, ZnAl0.4Zr0.6-LDH demonstrated superior decontamination performance for the sulfur mustard (HD) simulant 2-chloroethyl ethyl sulfide (CEES) compared to ZnAl-LDH, effectively catalyzing the detoxification of CEES into dehydrohalogenation (EVS) and 1,2-bis-(ethylthio) ethane (BETE). ZnAl0.4Zr0.6-LDH also had satisfactory decontamination performance against HD. This work provides not only a green and efficient catalyst with potential for practical applications but also new insights for constructing broad-spectrum, highly efficient self-detoxifying materials.

Highly Mesoporous Zr-Based MOF-Fabric Composites: A Benign Approach for Expeditious Degradation of Chemical Warfare Agents and Simulants

Recent research has demonstrated the degradation of organophosphonates through hydrolysis using microporous UiO-66-NH2-fabric composites. Yet, challenges remain due to the limitations of organophosphonates accessing active sites in large, engineered granules. To address this, an innovative approach to integrate mesoporous UiO-66-NH2 onto various fabrics is provided, thereby overcoming previous mass transfer limitations. Mesoporosity in the UiO-66-NH2-fabric is attributed to the amphoteric cocamidopropylbetaine (CAPB) surfactant which templates the mesochannel construction. Unexpectedly, because the synthesis is aqueous, benign, low temperature (60°C), and avoids strong acids and toxic solvents, it is compatible with fragile supports such as untreated cotton. The UiO-66-NH2-fabric composite formed using treated polypropylene (PP) attains a BET specific surface area of 360 m2 g-1 comp. Remarkably, the mesoporous UiO-66-NH2-composites exhibit a pore volume as large as 0.2 cm3 g-1 comp, 33% in the mesoporous range, which is higher than other previous reports. Practically, the mesoporous UiO-66-NH2-treated PP composite enhances the rate of methyl paraoxon (DMNP) degradation, showing a t1/2 value that is 15 times faster than microporous UiO-66-NH2 composites measured under the same conditions. Similar trends are observed in the degradation of actual nerve agents. These composites hold significant potential across diverse applications, including filtration, protection, and catalysis.

Permeable Self-Association of Metal-Organic Framework 808/Ag-Based Fiber Membrane for Broad-Spectrum and Highly Efficient Degradation of Biological and Chemical War Agents

The threat posed by biological and chemical warfare agents (BCWA) to national security, the environment, and personal health underscores the need for innovative chemical protective clothing. To address the limitations of conventional activated carbon materials, which are prone to falling off and adsorption saturation, an efficient self-association approach was introduced. In this study, we proposed the immobilization of metal-organic framework (MOF) 808 and Ag nanoparticles onto a polypropylene (PP) fiber membrane using a rapid self-association method facilitated by chitosan (CS). The MOF 808/Ag-based (PP-CS/808-Ag) fiber membrane demonstrated exceptional degradation efficiency, achieving a remarkable rate of t1/2 within 2 h for the mustard simulant 2-chloroethyl ethyl sulfide (2-CEES) and a rate of t1/2 = 4.12 min for the G-series simulant dimethyl 4-nitrophenylphosphate (DMNP). A theoretical computational model was developed to determine the overall reaction mechanism, and it was verified that MOF 808 and Ag nanoparticles were mainly involved in the hydrolysis process against 2-CEES and DMNP. The PP-CS/808-Ag composite fiber film was prepared as the core layer, and the fracture strength, bending resistance, and moisture permeability were better than those specified by many countries for biochemical protective clothing, showing that it has a broad application prospect in developing a generation of broad-spectrum bioprotective clothing.

Ultrathin photonic crystal based on photo-crosslinked polymer and metal-organic framework for highly sensitive detection and discrimination of benzene series vapors

Volatile organic compounds (VOCs) have always been a major concern as a global environmental problem. As a low-cost, high-efficiency and visual sensor, photonic crystals (PCs) have been actively studied in VOCs detection. Herein, a one-dimensional PC sensor for visual sensing of highly toxic benzene series VOC vapors is prepared for the first time by integrating a new photo-crosslinked polymer-poly(styrene-benzoylphenyl acrylate) P(St-BPA) and a high specific surface area metal-organic framework (MOF) MIL-101(Cr). The PC can detect VOCs quantitatively and visually, and clearly distinguish 7 benzene series vapors. The detection limit of the benzene series VOCs is as low as 0.06-3.45 g/m3. Meanwhile, owing to the ultra-thin layer and porous structure, the PC can reach a response equilibrium to the VOCs within 1-2.6 s. Moreover, the PC has a good organic vapor tolerance and can maintain stable optical performance after 1000 times of reuse in VOCs. Besides, 4 other PCs assembled with different aryl polymers and MOFs are first fabricated and their sensing performance to benzene series VOCs are studied and compared, which provides a valuable reference for the selection of materials for the preparation of such PC sensors.