Search Results (51)

Chemical warfare agents (CWAs) pose severe threats to human health and the environment because of their extreme toxicity. Conventional liquid-phase decontamination processes can present limitations, including potential equipment corrosion, generation of secondary liquid waste, and increased operational complexity. To overcome these challenges, we report a solar-assisted process intensification strategy for solvent-free decontamination of toxic organophosphorus compounds using UiO-66-NH₂@carbon nanotube (CNT) hybrid platforms. Incorporation of CNTs (optimized at 5 wt%) enables efficient solar-to-thermal conversion, resulting in rapid photothermal self-heating to 85 °C under simulated solar irradiation (1000 W m⁻²). This localized thermal effect contributes to accelerated DMMP removal within the MOF-based hybrid structure, thereby partially alleviating the kinetic limitations typically associated with solvent-free reactions. Consequently, the optimized hybrid achieves 94% removal of dimethyl methylphosphonate (DMMP), a representative sarin simulant, within 10 min under humidity-conditioned, solvent-free conditions, representing a 27% improvement compared with pristine UiO-66-NH₂. This decontamination platform eliminates the need for chemical solvents and external energy input, thereby mitigating secondary contamination and reducing the environmental footprint. By integrating the catalytic framework of Zr-based MOFs with the photothermal capability of CNTs, this study presents a sustainable engineering strategy for advanced defense and environmental protection. Full article

Iron-exchanged bentonites derived from a natural montmorillonite-rich clay (Taganskoe deposit, Kazakhstan) were prepared through a simple aqueous ion-exchange route using Fe(II) or Fe(III) inorganic salt precursors, yielding final Fe contents of ca. 5–7 wt.%, while preserving the smectite layered framework. A mild thermal treatment under air was applied to tune iron coordination without triggering major structural collapse. The resulting materials were characterized by ED-XRF, PXRD, FE-SEM/EDX, DLS/ζ-potential and DR UV–Vis–NIR spectroscopy, revealing predominantly exchanged Fe species with a limited fraction of surface iron-oxide clusters, whose contribution increases after activation. Structure–reactivity relationships were probed under mild conditions in liquid-phase ethyl acetate using dimethyl methylphosphonate (DMMP) and 2-chloroethyl ethyl sulfide (2-CEES) as organophosphorus and organosulfur hazardous chemicals and chemical warfare agent simulants, respectively. Fe(III)-bentonite enabled very fast DMMP removal (ca. 93% within 0.5 h) with a remarkable improved performance with respect to Fe(II)-bentonite and the pristine mineral clay. For 2-CEES, the presence of H₂O₂ markedly enhanced oxidation on Fe-containing clays, reaching quantitative abatement within 24 h (up to >90%), with strong retention of oxidized sulfur products by the clay matrix. These results highlight Fe-exchanged natural bentonites as robust, cheap and multifunctional adsorption/catalytic solids for decontamination and water-treatment applications. Full article

The practical adoption of surface-enhanced Raman scattering (SERS) technology is often hampered by the high cost, complex fabrication, and poor reproducibility of conventional substrates, which typically rely on noble metals or inefficient semiconductors. Herein, we address key challenges in the practical commercialization of surface-enhanced Raman scattering (SERS) technology by reporting a facile, scalable, and environmentally benign strategy for fabricating a hybrid SERS substrate. This approach integrates Au nanoparticles (NPs) with hydrothermally synthesized WO₃ nanowires through a green photoreduction process, which is rapid, organic-solvent-free, and amenable to large-scale production. The design of the Au/WO₃ nanocomposite capitalizes on the synergistic effect between electromagnetic (EM) enhancement from Au NPs and chemical mechanism (CM) enhancement via charge transfer involving the WO₃ semiconductor. This synergy empowers the substrate with exceptional SERS activity, enabling the sensitive detection of Rhodamine 6G (R6G) down to 10⁻¹¹ M and yielding an enhancement factor (EF) of 4.09 × 10⁶. More importantly, this EM-CM synergy proves critical for detecting molecules with weak affinity, such as the nerve agent simulant dimethyl methylphosphonate (DMMP), achieving a significant signal enhancement of 10²–10³ times, which is notably challenging for conventional plasmonic substrates. Beyond sensitivity, the substrate exhibits excellent reproducibility and operational stability, which are paramount for real-world applications. This work presents a nanohybrid strategy that successfully balances scalability, stability, and sensitivity, offering a reliable and cost-effective pathway for advancing SERS technologies toward practical implementation. Full article

Rapid on-site detection of chemical warfare agents (CWAs) is vital for security and environmental monitoring. In this work, copper(I) oxide (Cu₂O) nanowire (NW) chemiresistors were investigated as gas sensors for low-concentration organophosphorus chemical warfare agent (CWA) simulants. The NWs were hydrothermally synthesized and deposited onto microheater platforms, enabling them to operate at elevated working temperatures. Their sensing performance was tested against a range of vapor-phase simulants, including dimethyl methylphosphonate (DMMP), triethyl phosphate (TEP), diethyl ethylphosphonate (DEEP), diphenyl phosphoryl chloride (DPPCl), parathion, diethyl phosphite (DEP), diethyl adipate (DEA), and cyanogen chloride (ClCN). Fully oxidized P(V) simulants (DMMP, DEEP, TEP) produced modest, predominantly reversible responses (~3–6% RR). On the contrary, DPPCl and DEP induced the strongest relative responses (RR −94.67% and >200%, respectively), accompanied by irreversible surface modification as revealed by SEM and EDS. ClCN produced a substantial but reversible negative response (RR −9.5%), consistent with transient oxidative interactions. Surface poisoning was confirmed after exposure to DEP and DPPCl, which left phosphorus or chlorine residues on the Cu₂O surface. These results highlight both the promise and limitations of Cu₂O NW chemiresistors for selective CWA detection. Full article

Timely detection of organophosphates in outdoor environments remains a critical challenge for forensic and environmental monitoring. Traditional methods often require transporting samples to centralised laboratories, delaying essential response actions. In this study, we present a novel mobile analytical chemistry workstation that integrates capillary electrophoresis (CE) with capacitively coupled contactless conductivity detection (C4D) on low-cost polydimethylsiloxane (PDMS) microfluidic chips, enabling rapid and accurate on-site analysis of organophosphates. The system features a streamlined workflow that includes in-field sample collection, microfluidic analysis, and the wireless transmission of data to a central command centre for immediate decision-making. The detection system demonstrates a linear range of 2.5 mM to 20 mM for dimethyl methylphosphonate (DMMP), with an estimated limit of detection (LOD) of 2.5 mM. We evaluate the feasibility of combining CE and C4D under field conditions, highlighting both the strengths and limitations of this integrated platform. Full article

Sarin is an extremely toxic and fast-acting chemical warfare nerve agent that poses a serious threat to human health, necessitating the development of appropriate sensing technologies. Dimethyl methylphosphonate (DMMP), which has a chemical structure similar to that of sarin but is non-toxic, is often used as a simulation agent in related research. Among promising gas-sensing materials, CuFe₂O₄ exhibits suitable thermal stability. It is easily produced and has low toxicity. Its performance can be enhanced using heterogeneous ion doping to increase the number of surface defects and content of adsorbed oxygen. Therefore, a solvothermal method was adopted in this study to prepare CuFe₂O₄ hollow microspheres that were subsequently doped with different ratios of Sn⁴⁺ or Sn²⁺. Detailed characterizations of the obtained materials were conducted, and the corresponding CuFe₂O₄-based gas sensors were fabricated. Their gas-sensing performance against DMMP was studied to analyze and discuss the gas-sensing and sensitization mechanisms associated with Sn⁴⁺ and Sn²⁺ doping. The CuFe₂O₄-based sensor doped with 2 mol% Sn²⁺ exhibited excellent gas-sensing performance in response to a 1 ppm concentration of DMMP, with response and recovery times of 12 and 63 s, respectively. Notably, its response to 1 ppm DMMP (16.27) was 3.3-fold higher than that to 1 ppm 2-CEES (4.98). The doped CuFe₂O₄ sensor exhibited superior response–recovery characteristics and enhanced moisture resistance compared to the undoped sensor. Full article

A Pt@CeLaCoNiOx/Co@SnO₂ laminated MOS sensor was prepared using Co@SnO₂ as the gas-sensitive film material and Pt@CeLaCoNiOx as the catalytic film material. The sensor was verified to exhibit good sensing performances for dimethyl methylphosphonate, a simulant of Sarin, under a temperature modulation, and characteristic peaks appeared in the resistance response curves only for dimethyl methylphosphonate. The Article Swarm Optimization-Backpropagation Neural Network had a good ability to identify the resistance response data of dimethyl methylphosphonate. The identification accuracy increased as the concentration of dimethyl methylphosphonate increased. This scheme can effectively identify whether the test gas contained dimethyl methylphosphonate or not, which provided a reference for achieving the high selectivity of the MOS sensor for Sarin. Full article

Dimethyl methylphosphonate (DMMP) and modified nano-silica were utilised to enhance the mechanical properties, thermal stability, and flame retardancy of waterborne polyurethane (WPU). Nano-silica modified with the silane coupling agent γ-aminopropyltriethoxysilane (KH550) exhibited excellent dispersibility and stability. Compared with pure WPU, the limiting oxygen index (LOI) of P/Si-WPU increased from 18.1% to 28.3%, and its UL-94 rating reached V-0, with a significant improvement in elongation at break. Furthermore, the peak heat release rate of P/Si-WPU decreased by 29.1%, while the total heat release was reduced by 6.8% in comparison to pure WPU. The synergistic flame-retardant mechanism of phosphorus and silicon was investigated through an analysis of the char residue of WPU and its composites. This study provides a potential approach for the development of WPU with superior flame retardancy and enhanced mechanical properties. Full article

Nerve agents, a highly toxic class of chemical warfare agents, pose serious risks to human health and social stability. Metal oxides are commonly used as catalysts to break down these agents through thermocatalytic decomposition. In particular, bimetallic oxide catalysts offer enhanced stability and catalytic efficiency due to their synergistic effects. In this study, CuO/ZrO₂ composite catalysts with varying Cu/Zr ratios were synthesized using a secondary hydrothermal method, resulting in a hollow microsphere morphology. The catalytic efficiency of these composites in thermocatalytically decomposing dimethyl methylphosphonate (DMMP), a sarin simulant, was systematically evaluated. The findings revealed that the catalyst with a 10%Cu/Zr ratio exhibited the best performance, achieving the longest protection duration of 272 min. The hollow microsphere structure facilitated high dispersion of CuO on the ZrO₂ surface, promoting strong interactions and generation of oxygen vacancies, which enhanced the catalytic activity. Furthermore, the catalytic reaction mechanism was explored by analyzing the surface characteristics of the catalyst and the resulting reaction products. This research addresses a gap in the application of CuO/ZrO₂ catalysts for DMMP decomposition and provides valuable insights for the future development of catalysts for chemical warfare agent degradation. Full article

We report the exfoliation of ultrathin gallium oxide (Ga₂O₃) films from liquid metal balloons, formed by injecting air into droplets of eutectic gallium–indium alloy (eGaIn). These Ga₂O₃ films enable the selective adsorption of carbon nanotubes (CNTs) dispersed in water, resulting in the formation of a dense, percolating CNT network on their surface. The self-assembled CNT network on Ga₂O₃ provides a versatile platform for device fabrication. As an example application, we fabricated a chemiresistive gas sensor for detecting simulants of chemical warfare agents (CWAs), including diisopropyl methylphosphonate (DIMP), dimethyl methylphosphonate (DMMP), and triethyl phosphate (TEP). The sensor exhibited reversible responses, high sensitivity, and low limits of detection (13 ppb for DIMP, 28 ppb for DMMP, and 53 ppb for TEP). These findings highlight the potential of Ga₂O₃ films derived from liquid metal balloons for integrating CNTs into functional electronic devices. Full article

In the present study, we used two popular radio communication SAW resonators as a base for gas sensors and tested their performance. Taking into account issues related to sensor sensitivity, the possibility of applying a sensor layer, the availability of devices, and other related issues, we selected two popular single-port resonators with center frequencies of 315 and 433 MHz (models R315 and R433, respectively) for testing purposes. Both resonators were equipped with a sensitive film of hexafluoroisopropanol-substituted polydimethylsiloxane, a material that selectively absorbs molecules with a high ability to form basic hydrogen bonds. Fabricated sensors were used to detect trace amounts of dimethyl methylphosphonate (DMMP) vapor, which has often been used in similar studies as a nerve chemical warfare agent simulant. Sensors using both devices loaded with sensor layers of an optimal thickness rapidly reacted to a gas containing DMMP at a concentration of 3 mg/m³, generating a stable analytical signal ranging from several to several dozen kilohertz. In the case of R433, the frequency signal was 20.5 kHz at 1 min from the beginning of exposure to DMMP. The obtained results showed that the used transducers exhibited good performance as a base for gas sensors. Finally, their suitability for sensing applications was confirmed by a comparison with the results obtained in previous similar studies. Full article

Ultraviolet (UV) curing is an efficient and environmentally friendly curing method. In this paper, UV-cured polyurethane acrylates (PUAs) were investigated as potential military coatings to serve as barriers against chemical warfare agents (CWAs). Seven UV-cured PUA coatings were formulated utilizing hydroxyethyl methacrylate-capped hexamethylene diisocyanate trimer (HEMA-Htri) and trimethylolpropane triacrylate-capped polycarbonate prepolymer (PETA-PCDL) as the PUA monomers. Isobornyl acrylate (IBOA) and triethyleneglycol divinyl ether (DVE-3) were employed as reactive diluents. Gas chromatography was utilized to investigate the constitutive relationships between the structures of the PUA coatings and their protective properties against simulant agents for CWAs, including dimethyl methylphosphonate (DMMP), a nerve agent simulant, and 2-chloroethyl ethyl sulfide (CEES), a mustard simulant. The glass transition temperature (T_g) and crosslinking density (υ_e) of PUAs were found to be crucial factors affecting their ability to serve as barriers against CWAs. The incorporation of IBOA units led to enhanced T_g and barrier performance of the PUAs, resulting in a DMMP retention of less than 0.5% and nearly 0 retention of CEES. However, an excessive introduction of polycarbonate chains decreased the υ_e and barrier performance of the PUAs. These findings may offer valuable insights for enhancing the protection of UV-cured PU coatings against CWAs. Full article

Thermocatalytic decomposition is an efficient purification technology that is potentially applicable to degrading chemical warfare agents and industrial toxic gases. In particular, ZrO₂ has attracted attention as a catalyst for the thermocatalytic decomposition of dimethyl methylphosphonate (DMMP), which is a simulant of the nerve gas sarin. However, the influence of the crystal phase and morphology on the catalytic performance of ZrO₂ requires further exploration. In this study, monoclinic- and tetragonal-phase ZrO₂ (m- and t-ZrO₂, respectively) with nanoparticle, flower-like shape and hollow microsphere morphologies were prepared via hydrothermal and solvothermal methods, and their thermocatalytic decomposition of DMMP was systematically investigated. For a given morphology, m-ZrO₂ performed better than t-ZrO₂. For a given crystalline phase, the morphology of hollow microspheres resulted in the longest protection time. The exhaust gases generated by the thermocatalytic decomposition of DMMP mainly comprised H₂, CO₂, H₂O and CH₃OH, and the by-products were phosphorus oxide species. Thus, the deactivation of ZrO₂ was attributed to the deposition of these phosphorous oxide species on the catalyst surface. These results are expected to help guide the development of catalysts for the safe disposal of chemical warfare agents. Full article

New and efficient sensors of nerve agents are urgently demanded to prevent them from causing mass casualties in war or terrorist attacks. So, in this work, a novel hierarchical nanoheterostructure was synthesized via the direct growth of α-Fe₂O₃ nanorods onto multiwall carbon nanotube (MWCNT) backbones. Then, the composites were functionalized with hexafluoroisopropanol (HFIP) and successfully applied to detect dimethyl methylphosphonate (DMMP)-sarin simulant gas. The observations show that the HFIP-α-Fe₂O₃@MWCNT hybrids exhibit outstanding DMMP-sensing performance, including low operating temperature (220 °C), high response (6.0 to 0.1 ppm DMMP), short response/recovery time (8.7 s/11.9 s), as well as low detection limit (63.92 ppb). The analysis of the sensing mechanism demonstrates that the perfect sensing performance is mainly due to the synergistic effect of the chemical interaction of DMMP with the heterostructure and the physical adsorption of DMMP by hydrogen bonds with HFIP that are grafted on the α-Fe₂O₃@MWCNTs composite. The huge specific surface area of HFIP-α-Fe₂O₃@MWCNTs composite is also one of the reasons for this enhanced performance. This work not only offers a promising and effective method for synthesizing sensitive materials for high-performance gas sensors but also provides insight into the sensing mechanism of DMMP. Full article

The increasing threat of nerve agents has prompted the need for gas sensors with fast response, high sensitivity, and good stability. In this work, the hexafluoroisopropanol functional group was modified on a porous aromatic framework material, which served as a sensitive material for detecting dimethyl methylphosphonate. A nerve agent sensor was made by coating sensitive materials on a surface acoustic wave device. Lots of pores in sensitive materials effectively increase the specific surface area and provide channels for diffusion of gas molecules. The introduction of hexafluoroisopropanols enables the sensor to specifically adsorb dimethyl methylphosphonate and improves the selectivity of the sensor. As a result, the developed gas sensor was able to detect dimethyl methylphosphonate at 0.8 ppm with response/recovery times of 29.8/43.8 s, and the detection limit of the gas sensor is about 0.11 ppm. The effects of temperature and humidity on the sensor were studied. The results show that the baseline of the sensor has a linear relationship with temperature and humidity, and the temperature and humidity have a significant effect on the response of the sensor. Furthermore, a device for real-time detection of nerve agent is reported. This work provides a new strategy for developing a gas sensor for detecting nerve agents. Full article