A Catalytically Accessible Polyoxometalate in a Porous Fiber for Degradation of a Mustard Gas Simulant

Polyoxometalates (POMs) are versatile materials for chemical catalysis due to their tunable acidity and rich redox properties. While POMs have attracted significant attention in homogeneous catalysis, challenges regarding aggregation and instability in solvents often prevent the wide implementation of POMs as heterogeneous catalysts. Therefore, the successful incorporation of a POM into a solid support, such as a polymer, is desirable for practical applications where unique functionalities of the POM combine with the advantages of the polymer. In this work, we showcase how polymers of intrinsic microporosity (PIMs) can serve as matrices for anchoring a pure inorganic Keggin-type POM (H₃PW₁₂O₄₀) to fabricate PIM-based composite materials. Specifically, we found that PIMs installed with amidoxime functionalities could successfully attach POMs (PW₁₂@PIM-1-AO) without self-segregation. Furthermore, we fabricated porous fibrous mats via electrospinning of the PIM-POM composites. Comprehensive characterization confirmed the integrity of the POM in the composite material. Following this, we demonstrated that the incorporated POMs in the composite fibers maintained their innate catalytic activity for the oxidative degradation of 2-chloroethyl ethyl sulfide, a sulfur mustard simulant, in the presence of hydrogen peroxide as the oxidant. Ultimately, our work highlights that PIM-based hybrid materials provide a potential route for implementing these reactive fiber mats into protective equipment.

Recent advances in amphiphilic block copolymer templated mesoporous metal-based materials: assembly engineering and applications

Mesoporous metal-based materials (MMBMs) have received unprecedented attention in catalysis, sensing, and energy storage and conversion owing to their unique electronic structures, uniform mesopore size and high specific surface area. In the last decade, great progress has been made in the design and application of MMBMs; in particular, many novel assembly engineering methods and strategies based on amphiphilic block copolymers as structure-directing agents have also been developed for the "bottom-up" construction of a variety of MMBMs. Development of MMBMs is therefore of significant importance from both academic and practical points of view. In this review, we provide a systematic elaboration of the molecular assembly methods and strategies for MMBMs, such as tuning the driving force between amphiphilic block copolymers and various precursors (i.e., metal salts, nanoparticles/clusters and polyoxometalates) for pore characteristics and physicochemical properties. The structure-performance relationship of MMBMs (e.g., pore size, surface area, crystallinity and crystal structure) based on various spectroscopy analysis techniques and density functional theory (DFT) calculation is discussed and the influence of the surface/interfacial properties of MMBMs (e.g., active surfaces, heterojunctions, binding sites and acid-base properties) in various applications is also included. The prospect of accurately designing functional mesoporous materials and future research directions in the field of MMBMs is pointed out in this review, and it will open a new avenue for the inorganic-organic assembly in various fields.

An efficient ordered mesoporous molybdate-zirconium oxophosphate solid acid catalyst with homogeneously dispersed active sites: Synthesis, characterization and application

Ordered mesoporous molybdate-zirconium oxophosphate (M-ZrPMo) solid acid catalysts with controllable molybdenum contents (0-20%) are designed and synthesized through a one-pot evaporation-induced self-assembly strategy. Afterwards, ordered mesostructure and molybdenum species in the materials are systematically researched by a variety of means. The results show that M-ZrPMo has highly ordered mesoporous structure with large specific surface area (∼200 m²·g^-1), big pore volume (∼0.30 cm³·g^-1) and pore size (∼6.5 nm). Additionally, ordered mesoporous structure of M-ZrPMo can be efficiently preserved even treated at 700 °C, presenting an outstanding thermal stability. Meanwhile, the molybdenum species are introduced as designed and homogeneously dispersed in mesoporous framework even at molybdenum content up to 20%. More importantly, the Brønsted and Lewis acidic properties of these materials are successfully enhanced with the introduction of molybdenum species. Meantime, the M-ZrPMo is employed as a solid acid catalyst for alkylation of aromatic compounds and esterification of levulinic acid with 1-butanol. The effect of molybdenum contents and calcination temperature on catalytic performance is thoroughly discussed. The excellent activity and reusability suggested that M-ZrPMo is a promising solid acid catalyst.

Aluminum-substituted phosphotungstic acid/sulfonated poly ether ether ketone nanocomposite membrane with reduced leaching and improved proton conductivity

Aluminum-substituted tungstophosphoric acid (AlTPA)/sulfonated poly ether ether ketone (SPEEK) (sulfonation degree approximately 77%) nanocomposite membranes have been prepared for fuel cell application. AlTPA nanoparticles are synthesized by the reaction of TPA and aluminum nitrate in aqueous medium. X-ray diffraction, energy dispersive X-ray, Fourier transform infrared and Raman spectroscopies, and field-emission scanning electron microscopy (FESEM) are used to characterize the AlTPA particles and SPEEK. Study reveals that 2.31 numbers of protons of TPA have been replaced by Al3+ in AlTPA with retention of Keggin’s structure. Nanocomposite membranes with varying AlTPA and TPA content are prepared and evaluated by measuring water uptake, ion exchange capacity, equilibrium water content, water desorption rate, proton conductivity, leaching tendency, and thermal properties. SPEEK/AlTPA nanocomposite membrane exhibits proton conductivity as high as 1.09 mS cm−1 at 10 wt% filler loading. Leaching of filler is reduced by approximately 92% in SPEEK/AlTPA nanocomposite membrane compared to SPEEK/TPA membrane. SPEEK/AlTPA membrane shows approximately 15% higher equilibrium water content and approximately 57% reduction in water desorption rate as compared to SPEEK/TPA membrane. Membranes are thermally stable up to 215°C, which is well above the operating temperature of fuel cells. Composite films are also examined by FESEM to gain further insights into the microstructure.

Efficient biodiesel production via solid superacid catalysis: a critical review on recent breakthrough

Biodiesel produced from triglycerides and/or free fatty acids (FFAs) by transesterification and esterification has attracted immense attention during the past decades as a biodegradable, renewable and sustainable fuel.

Green photocatalytic organic transformations by polyoxometalates vs. mesoporous TiO2 nanoparticles: selective aerobic oxidation of alcohols

Decatungstate supported on mesoporous TiO₂ nanoparticle assemblies catalyze the selective and efficient oxidation of aromatic alcohols under “green” oxidation conditions. An electron transfer mechanism was predominated under UV-vis irradiation.

Ordered Porous Nanomaterials: The Merit of Small

This paper will introduce the reader to some of the “classical” and “new” families of ordered porous materials which have arisen throughout the past decades and/or years. From what is perhaps the best-known family of zeolites, which even now to this day is under constant research, to the exciting new family of hierarchical porous materials, the number of strategies, structures, porous textures, and potential applications grows with every passing day. We will attempt to put these new families into perspective from a synthetic and applied point of view in order to give the reader as broad a perspective as possible into these exciting materials.

Ordered mesoporous metal oxides: synthesis and applications

Great progress has been made in the preparation and application of ordered mesoporous metal oxides during the past decade. However, the applications of these novel and interesting materials have not been reviewed comprehensively in the literature. In the current review we first describe different methods for the preparation of ordered mesoporous metal oxides; we then review their applications in energy conversion and storage, catalysis, sensing, adsorption and separation. The correlations between the textural properties of ordered mesoporous metal oxides and their specific performance are highlighted in different examples, including the rate of Li intercalation, sensing, and the magnetic properties. These results demonstrate that the mesoporosity has a direct impact on the properties and potential applications of such materials. Although the scope of the current review is limited to ordered mesoporous metal oxides, we believe that the information may be useful for those working in a number of fields.