Ultrathin Zirconium Hydroxide Nanosheet-Assembled Nanofibrous Membranes for Rapid Degradation of Chemical Warfare Agents

Atomic layer deposition paves the way for next-generation smart and functional textiles

As technology evolves and consumer needs diversify, textiles have become crucial to determining the future of fashion, sustainability, and functionality. Functional textiles, which not only provide comfort and aesthetics as traditional textiles but also endow textiles with special functions such as antibacterial, anti-odor, moisture absorption and perspiration, anti-ultraviolet (UV), flame-retardant, self-cleaning, and anti-static properties through technological innovation and upgrading, have attracted increasing attention because they satisfy the specific needs of people in different environments and occasions. However, functionality often occurs at the expense of comfort in existing functional products. Endowing textiles with excellent multi-functionality with marginal effects on comfort and wearability properties continues to be a challenge. Atomic layer deposition (ALD) paves the way for creating functional fabrics by enabling the formation of highly conforming inorganic/organic coatings over a large area with precise atomic-level film thickness control from a self-limiting reaction mechanism. Therefore, this paper introduces the reaction mechanism of ALD and the unique advantages of depositing inorganic nanofilms on fiber and textile surfaces. The factors influencing ALD and the commonly used ALD-derived technologies are then discussed. Subsequently, the research progress and breakthroughs in inorganic nanofilms prepared by ALD in conferring multifunctional properties on textile surfaces, such as antimicrobial, UV-resistant, heat-insulating, multifunctional wetting, structural coloring, thermoelectric elements, and flexible sensing, are reviewed. Finally, future developments and possible challenges of ALD for the large-scale production of multifunctional fabrics are proposed, which are expected to promote the development of next-generation advanced functional textiles.

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.

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.

Design and Advanced Manufacturing of NU-1000 Metal-Organic Frameworks with Future Perspectives for Environmental and Renewable Energy Applications

Metal-organic frameworks (MOFs) represent a relatively new family of materials that attract lots of attention thanks to their unique features such as hierarchical porosity, active metal centers, versatility of linkers/metal nodes, and large surface area. Among the extended list of MOFs, Zr-based-MOFs demonstrate comparably superior chemical and thermal stabilities, making them ideal candidates for energy and environmental applications. As a Zr-MOF, NU-1000 is first synthesized at Northwestern University. A comprehensive review of various approaches to the synthesis of NU-1000 MOFs for obtaining unique surface properties (e.g., diverse surface morphologies, large surface area, and particular pore size distribution) and their applications in the catalysis (electro-, and photo-catalysis), CO2 reduction, batteries, hydrogen storage, gas storage/separation, and other environmental fields are presented. The review further outlines the current challenges in the development of NU-1000 MOFs and their derivatives in practical applications, revealing areas for future investigation.

Starfruit-Shaped Zirconium Metal-Organic Frameworks: From 3D Intermediates to 2D Nanosheet Petals with Enhanced Catalytic Activity

We present the fabrication of a novel Starfruit-shaped metal-organic framework (SMOF) composed of zirconium and Tetra(4-carboxyphenyl)porphine linkers. The SMOF exhibits a unique morphology with edge-sharing two-dimensional (2D) nanosheet petals. Our investigation unravels a captivating transformation process, wherein three-dimensional (3D) shuttle-shaped MOFs form initially and subsequently evolve into 2D nanosheet-based SMOF structures. The distinct morphology of SMOF showcases superior catalytic activity in detoxifying G-type nerve agent and blister agent simulants, surpassing that of its 3D counterparts. This discovery of the 3D-to-2D transition growth pathway unlocks exciting opportunities for exploring novel strategies in advanced MOF nanostructure development, not only for catalysis but also for various other applications.

Superelastic and Photothermal RGO/Zr-Doped TiO2 Nanofibrous Aerogels Enable the Rapid Decomposition of Chemical Warfare Agents

To date, the reckless use of deadly chemical warfare agents (CWAs) has posed serious risks to humanity, property, and ecological environment. Therefore, necessary materials able to rapidly adsorb and securely decompose these hazardous toxics are in urgent demand. Herein, three-dimensional (3D) reduced graphene oxide/Zr-doped TiO₂ nanofibrous aerogels (RGO/ZT NAs) are synthesized by feasibly combining sol-gel electrospinning technology and a unidirectional freeze-drying approach. Benefiting from the synergetic coassembly of flexible ZT nanofibers and pliable RGO nanosheets, the hierarchically entangled fibrous frameworks feature ultralow density, superior elasticity, and robust fatigue resistance over 10⁶ compressive cycles. In particular, the RGO incorporation is attributed to the achieved increased surface area, stronger light absorption, and decreased recombination of charge-carriers for photocatalysis. The highly porous 3D RGO/ZT NAs deliver enhanced photothermal catalytic activity for CWA degradation as well as excellent recyclability and good photostability. This work opens fresh horizons for developing advanced 3D aerogel-based photocatalysts in a controlled fashion.

Superelastic, Breathable, and High-Barrier Nanofibrous Membranes with Biomimetic ECM Structure for Toxic Chemical Protection

As the last line of protection for humans, chemical protective suits provided safe and effective protection where chemical warfare agents (CWAs) or chemical reagents leaked; however, the existing chemical protective clothing had poor wearing pressure comfort due to the limitation of inherent materials. Herein, we reported a scalable strategy to fabricate chemical protective fabric (CPF) with a biomimetic extracellular matrix (ECM) barrier layer composed of an elastic fiber framework based on the cross-linked nanofiber membrane and the styrene-butadiene-styrene block copolymer (SBS)/acticarbon matrix. The construction of the reliable and strategical biomimetic ECM structure succeeded in fulfilling hazardous chemical barrier properties, recoverable deformation, and thermal comfort improvement. The resulting CPF exhibited waterproofness with exceeding 200 kPa hydrostatic pressure and exceptional WVT of 550.96 g m^-2 d^-1, rapid elastic recovery from a strain of 80%, high-cycle fatigue resistance, superior barrier performance against toxic chemicals, and keeping CEES resistance after 100 tensile loading cycles. The successful preparation of the fascinating biomimetic nanofibrous membrane may provide a particular research foundation for developing chemical protective clothing in the future.

Copper hydroxide nanosheets-assembled nanofibrous membranes for anti-biofouling water disinfection

Copper hydroxide (Cu(OH)₂) has been elected as a newly-emerging green disinfectant to deal with membrane biofouling in the treatment of bacteria-contaminated water; however, the decoration strategy of it with the granular form on membrane substrates limits the practical application. Here a novel surface-confined methodology was proposed for preparing freestanding Cu(OH)₂ nanosheet-assembled nanofibrous membranes (CNNMs) with the anti-biofouling property via the in-suit coprecipitation and heat-induced growth method. The vertically aligned Cu(OH)₂ nanosheets were in-suit rooted on the surface of the nanofiber scaffold with high binding fastness. The acquired CNNMs possess comprehensive performances of high porosity, prominent mechanical strength, fatigue resistance, and superior bactericidal efficiency of 99.999%, which endowed the CNNMs ultrahigh filtration fluxes (24000 L m^-2 h^-1) and durability to disinfect bacteria-containing water effectively. This facile strategy may throw light on manufacturing novel inorganic nanosheet-rooted nanofibrous membranes for water disinfection and public health.

Nanoflake-Engineered Zirconic Fibrous Aerogels with Parallel-Arrayed Conduits for Fast Nerve Agent Degradation

Chemical warfare agents (CWAs) pose huge threats to ecological environments, agriculture, and human health due to the turbulent international situation in contemporary society. Zirconium hydroxide (Zr(OH)₄) has captured the prime focus as an effective candidate for CWA decomposition but is often hindered by the isolated powder form. Here, we demonstrate a scalable three-dimensional space-confined synthetic strategy to fabricate nanoflake-engineered zirconic fibrous aerogels (NZFAs). Our strategy enables the stereoscopic Zr(OH)₄ nanoflakes vertically and evenly in situ grown on the interconnected fibrous framework, remarkably enlarging the surface area and providing rich active sites for CWA catalysis. The as-synthesized NZFAs exhibit intriguing properties of ultralow density (>0.37 mg cm^-3), shape-memory behavior under 90% strain, and robust fatigue resistance over 10⁶ compression cycles at 40% strain. Meanwhile, the high air permeability, prominent adsorptivity, and reusability make them state-of-the-art chemical protective materials. This work may provide an avenue for developing next-generation aerogel-based catalysts and beyond.

Dual-purpose high-efficiency air filter paper loaded with reactive zirconium hydroxide for the filtration aerosols and degradation of chemical warfare agents

Traditional air filter papers can only filter toxic aerosols without the function of decontamination. If the poison stagnating in the paper is desorbed, it may pose a secondary threat to personnel and make it more difficult to dispose of the scrapped paper. Using an alkali-free glass fiber as the base material and zirconium hydroxide as the decontaminant, a self-decontaminating air filter paper that can degrade HD and VX simultaneously was successfully prepared by an intra-pulp addition method, with high filtration efficiency, low pressure drop and moderate tensile strength. The physicochemical properties were characterized by FE-SEM, EDX, XRD and TGA, and the results indicated that Zr(OH)₄ was dispersed uniformly in the paper and filled in the interstices of the glass fiber. The preparation of the composite material had no impact on the structure of fibers and Zr(OH)₄. The preparation technology of the self-decontaminating air filter paper was optimized. It was found that the paper with a fiber grammage of 50 g m⁻², the adhesive of 2% and a Zr(OH)₄ retention rate of 175.0 wt% could completely degrade HD and VX, whose conversion rate exceeded 99.0%, and had a tensile strength of 0.1193 kN m⁻¹, a filtration efficiency of 99.995%, and a pressure drop of 313.6 Pa. Using GC-MS to detect the decontamination products, it was speculated that HD mainly underwent hydrolysis and elimination reactions, VX mainly underwent hydrolysis and polymerization reactions, and their products were non-toxic or low-toxic. The reaction kinetics of HD and VX on the paper was investigated and the half-lives were 2.6 h and 16.2 min, respectively, which demonstrated an outstanding degradation performance. This work manifested for the first time that the air filter paper can be optimized as an efficient self-decontaminating material, which will open up new possibilities for the design and manufacture of multifunctional protective materials.

Dual-functional air filter paper with addition of Zr(OH)₄ was prepared by an intra-pulp addition method, whose filtration performance is maintained while the decontamination performance is added for HD and VX.