Polyoxometalate-Ionic Liquids for Mitigating the Effects of Iron Gall Ink Corrosion on Cellulosic Supports

Iron gall ink (IGI), renowned for its indelibility, was the most important writing ink in the Western world from the 15th to the late 19th century. However, it is now known that IGIs induce acid-catalyzed hydrolysis and iron-catalyzed oxidation of the cellulose in historical paper documents. These mechanisms of deterioration cause significant damage to the writing support materials, including color alteration and burn-through appearance, and in the worst scenarios, physical disintegration of the supports. Minimally invasive, long-term effective conservation treatments that tackle the underlying mechanisms of IGI degradation and their corrosion effects are yet to be developed. This study introduces the deployment of hydrophobic and anticorrosive polyoxometalate-ionic liquids (POM-ILs) as colorless coatings to counteract IGI-corrosion of cellulosic supports. Model IGI-containing papers (mockups) were prepared, coated with POM-ILs, and artificially aged to assess the compatibility of POM-ILs with IGI-containing documents. Comprehensive monitoring using colorimetric and scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM/EDS) analyses showed minimal interference with the aesthetic properties and morphology of the IGI mockups. In addition, polyoxometalates (POMs) with vacant metal atom sites in the cluster shell can be used to coordinate free transition metal ions. The ability of a monolacunary Keggin-type polyoxotungstate to coordinate free Fe(II) from IGI solution was demonstrated using UV-vis analysis. This led to the formation of a dimeric species, [(SiW11O39Fe)2O]K12·28H2O, which was characterized by single-crystal X-ray diffraction. Altogether, this study points to POM-ILs as promising protective coatings for effectively preserving historical IGI-written heritage.

Multidentate polyoxometalate modification of metal nanoparticles with tunable electronic states

To respond to the increasing demands for practical applications, stabilization and property modulation of metal nanoparticles have emerged as a key research subject. Herein, we present a viable protocol for preparing small metal nanoparticles (<5 nm; Ag, Pd, Pt, and Ru) via multidentate polyoxometalate (POM, [SiW9O34]10-) modification. In addition to enhancing stability, the POMs can modulate the electronic states of metal nanoparticles. Moreover, immobilization of the POM-modified metal nanoparticles on solid supports enables further tuning of the electronic states via a cooperative effect between the POMs and the supports without altering the particle size. Notably, POM-modified Pd nanoparticles on carbon support exhibited superior catalytic activity and selectivity in hydrogenation reactions in comparison with the catalyst without the POM modification.

Recent Progress on Functionalized Nanoporous Heteropoly Acids: From Synthesis to Applications

Functionalized nanoporous heteropoly acids (HPAs) have garnered significant attention in recent years due to their enhanced surface area and porosity, as well as their potential for low-cost regeneration compared to bulk materials. This review aims to provide an overview of the recent advancements in the synthesis and applications of functionalized HPAs. We begin by introducing the fundamental properties of HPAs and their unique structure, followed by a comprehensive overview of the various approaches employed for the synthesis of functionalized HPAs, including salts, anchoring onto supports, and implementing mesoporous silica sieves. The potential applications of functionalized HPAs in various fields are also discussed, highlighting their boosted performance in a wide range of applications. Finally, we address the current challenges and present future prospects in the development of functionalized HPAs, particularly in the context of mesoporous HPAs. This review aims to provide a comprehensive summary of the recent progress in the field, highlighting the significant advancements made in the synthesis and applications of functionalized HPAs.

Hierarchically porous amino-functionalized nanoMOF network anchored phosphomolybdic acid for oxidative desulfurization and shaping application

The applications of hierarchically porous metal-organic frameworks (HP-MOFs) against traditional microporous counterparts for oxidative desulfurization (ODS) have triggered wide research interests due to their highly exposed accessible active sites and fast mass transfer of substrate molecules, particularly for the large-sized refractory sulfur compounds. Herein, a series of hierarchically porous amino-functionalized Zr-MOFs (HP-UiO-66-NH2-X) network with controllable mesopore sizes (3.5-9.2 nm) were firstly prepared through a template-free method, which were further utilized as anchoring support to bind the active phosphomolybdic acid (PMA) via the strong host-guest interaction to catalyze the ODS reaction. Benefitting from the hierarchically porous structure, accessible active sites and the strong host-guest interaction, the resultant PMA/HP-UiO-66-NH2-X exhibited excellent ODS performance, of which, the PMA/HP-UiO-66-NH2-9 with an appropriate mesopore size (4.0 nm) showed the highest catalytic activity, achieving a 99.9% removal of dibenzothiophene (DBT) within 60 min at 50 °C, far exceeding the microporous sample and PMA/HP-UiO-66. Furthermore, the scavenger experiments confirmed that •OH radical was the main reactive species and the density functional theory (DFT) calculations revealed that electron transfer (from amino group to PMA) made PMA react more easily with oxidant, thereby generating more •OH radical to promote the ODS reaction. Finally, from the industrial point of view, the powdered MOF nanoparticles (NPs) were in situ grown on the carboxymethyl cellulose (CMC) substrates and shaped into monolithic MOF-based catalysts, which still exhibited satisfying ODS performance in the case of model real fuel with good reusability, indicating its potential industrial application prospect.

Gold Nanoparticles Capped with a Novel Titanium(IV)-Containing Polyoxomolybdate Cluster: Selective and Enhanced Bactericidal Effect Against Escherichia coli

Bacterial infections are a public health threat of increasing concern in medical care systems; hence, the search for novel strategies to lower the use of antibiotics and their harmful effects becomes imperative. Herein, the antimicrobial performance of four polyoxometalate (POM)-stabilized gold nanoparticles (Au@POM) against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) as Gram-negative and Gram-positive bacteria models, respectively, is studied. The bactericidal studies performed, both in planktonic and sessile forms, evidence the antimicrobial potential of these hybrid nanostructures with selectivity toward Gram-negative species. In particular, the Au@GeMoTi composite with the novel [Ti2 (HGeMo7 O28 )2 ]10- POM capping ligand exhibits outstanding bactericidal efficiency with a minimum inhibitory concentration of just 3.12 µm for the E. coli strain, thus outperforming the other three Au@POM counterparts. GeMoTi represents the fourth example of a water-soluble TiIV -containing polyoxomolybdate, and among them, the first sandwich-type structure having heteroatoms in high-oxidation state. The evaluation of the bactericidal mechanisms of action points to the cell membrane hyperpolarization, disruption, and subsequent nucleotide leakage and the low cytotoxicity exerted on five different cell lines at antimicrobial doses demonstrates the antibiotic-like character. These studies highlight the successful design and development of a new POM-based nanomaterial able to eradicate Gram-negative bacteria without damaging mammalian cells.

Polyoxometalate-Stabilized Silver Nanoparticles and Hybrid Electrode Assembly Using Activated Carbon

The intersection between the field of hybrid materials and that of electrochemistry is a quickly expanding area. Hybrid combinations usually consist of two constituents, but new routes toward more complex and versatile electroactive hybrid designs are quickly emerging. The objective of the present work is to explore novel triple hybrid material integrating polyoxometalates (POMs), silver nanoparticles (Ag0 NPs), and activated carbon (AC) and to demonstrate its use as a hybrid electrode in a symmetric supercapacitor. The tri-component nanohybrid (AC/POM-Ag0 NPs) was fabricated through the combination of AC with pre-synthesized ∼27 nm POM-protected Ag0 NPs (POM-Ag0 NPs). The POM-Ag0 NPs were prepared using a green electrochemical method and characterized via UV-vis and IR spectroscopy, electron microscopy, dynamic light scattering (DLS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV). Afterward, the AC/POM-Ag0 NPs ternary nanocomposite material was constructed and characterized. The electrochemical behavior of AC/POM-Ag0 NPs' modified electrodes reveal that the nanomaterial is electroactive and exhibits a moderately higher specific capacitance (81 F/g after 20 cycles) than bare AC electrodes (75 F/g) in a symmetrical supercapacitor configuration in the voltage range 0 to 0.75 V and 20 mV/s, demonstrating the potential use of this type of tri-component nanohybrid for electrochemical applications.

Synthesis, Characterization, and Antibacterial Activity of Ni-Substituted Krebs-type Sandwich-Tungstobismuthates Functionalized with Amino Acids

Four new Ni-substituted Krebs-type sandwich-tungstobismuthates, K4Ni2[{Ni(β-ala)(H2O)2}2{Ni(H2O)}2{Ni(H2O)(η2-β-ala)}2(B-β-BiW9O33)2]·49H2O {(β-ala)4(Ni3)2(BiW9)2}, K3.5Na6.5[{Ni(η3-L-asp)}2(WO2)2(B-β-BiW9O33)2]·36H2O·L-asp {(L-asp)2(NiW)2(BiW9)2}, K4Na6[{Ni(gly)(H2O)2}2(WO2)2(B-β-BiW9O33)2]·86H2O {(gly)2(NiW)2(BiW9)2}, and K2Na8[{Ni(η2-serinol) (H2O)}2{Ni(H2O)2}2(B-β-BiW9O33)2]·42H2O {(serinol)2Ni4(BiW9)2} have been synthesized by one-pot solution methods. All compounds have been characterized in the solid state by single-crystal X-ray diffraction (SXRD), powder X-ray diffraction (PXRD), elemental and thermogravimetric analyses, and infrared spectroscopy (IR), as well as by UV-vis spectroscopy in solution. The antibacterial activity of all compounds was studied against four bacterial strains by the determination of the minimum inhibitory concentration (MIC). The results showed that only {(β-ala)4(Ni3)2(BiW9)2} demonstrates antibacterial activity (MIC is in the range from 8 to 256 μg/mL) compared to three other Ni-Krebs sandwiches.

Tunable Ordered Nanostructured Phases by Co-assembly of Amphiphilic Polyoxometalates and Pluronic Block Copolymers

The assembly of polyoxometalate (POM) metal-oxygen clusters into ordered nanostructures is attracting a growing interest for catalytic and sensing applications. However, assembly of ordered nanostructured POMs from solution can be impaired by aggregation, and the structural diversity is poorly understood. Here, we present a time-resolved small-angle X-ray scattering (SAXS) study of the co-assembly in aqueous solutions of amphiphilic organo-functionalized Wells-Dawson-type POMs with a Pluronic block copolymer over a wide concentration range in levitating droplets. SAXS analysis revealed the formation and subsequent transformation with increasing concentration of large vesicles, a lamellar phase, a mixture of two cubic phases that evolved into one dominating cubic phase, and eventually a hexagonal phase formed at concentrations above 110 mM. The structural versatility of co-assembled amphiphilic POMs and Pluronic block copolymers was supported by dissipative particle dynamics simulations and cryo-TEM.

Recent Advances in Hybrid Materials of Metal Nanoparticles and Polyoxometalates

Polyoxometalates (POMs), anionic metal-oxygen nanoclusters that possess various composition-dependent properties, are widely used to modify the existing properties of metal nanoparticles and to endow them with new ones. Herein, we present an overview of recent advances in hybrid materials that consist of metal nanoparticles and POMs. Following a brief introduction on the inception of this area and its development, representative properties and applications of these materials in various fields such as electrochemistry, photochemistry, and catalysis are introduced. We discuss how the combination of two classic inorganic materials facilitates cooperative and synergistic behavior, and we also give personal perspectives on the future development of this field.

Hierarchically porous single catalyst Ru/HPW/UiO-66 with synergistic acid/metal sites for one-pot catalytic synthesis of γ–Valerolactone

γ-valerolactone (GVL) is an important lignocellulosic platform molecule with huge potential for various industrial and chemical applications, which is usually produced by using Levulinic acid (LA) or its esters as...

A hierarchically multifunctional integrated catalyst with intimate and synergistic active sites for one-pot tandem catalysis

As a typical process-intensive strategy, a tandem reaction driven by a multifunctional catalyst is a paragon of the green catalytic process.

Self-assembly of amphiphilic polyoxometalates for the preparation of mesoporous polyoxometalate-titania catalysts

Amphiphilic polyoxometalate (POM) surfactants were prepared by covalently grafting double hydrophobic tails with chain lengths C12H25, C14H29, C16H33 or C18H37 onto the lacunary Wells-Dawson {P2W17O61} headgroup. The critical micelle concentrations (CMCs) of these novel surfactants in aqueous solutions were determined by conductivity, and micelle formation was studied by small angle neutron scattering (SANS). Surprisingly, the amphiphiles with longer hydrophobic tails tend to form less elongated and more globular micelles in water. The self-assembled amphiphilic polyoxometalates were used as templates in the hydrothermal synthesis of mesoporous TiO2 containing dispersed, immobilised {P2W17O61} units, which showed enhanced activity for the photodegradation of rhodamine B (RhB). The catalyst was recycled eight times with no loss of efficiency, demonstrating the stability of the hybrid structure. The amphiphilic polyoxometalates, therefore have excellent potential for the synthesis of various types of catalytically active porous materials.

Antagonistic mixing in micelles of amphiphilic polyoxometalates and hexaethylene glycol monododecyl ether

HYPOTHESIS

Polyoxometalates (POMs) are metal oxygen clusters with a range of interesting magnetic and catalytic properties. POMs with attached hydrocarbon chains show amphiphilic behaviour so we hypothesised that mixtures of a nonionic surfactant and anionic surfactants with a polyoxometalate cluster as headgroup would form mixed micelles, giving control of the POM density in the micelle, and which would differ in size and shape from micelles formed by the individual surfactants. Due to the high charge and large size of the POM, we suggested that these would be nonideal mixtures due to the complex interactions between the two types of surfactants. The nonideality and the micellar composition may be quantified using regular solution theory. With supplementary information provided by small-angle neutron scattering (SANS), an understanding of this unusual binary surfactant system can be established.

EXPERIMENTS

A systematic study was performed on mixed surfactant systems containing polyoxometalate-headed amphiphiles (K₁₀[P₂W₁₇O₆₁OSi₂(C_nH_2n+1)₂], abbreviated as P₂W₁₇-2C_n, where n = 12, 14 or 16) and hexaethylene glycol monododecyl ether (C₁₂EO₆). Critical micelle concentrations (CMCs) of these mixtures were measured and used to calculate the interaction parameters based on regular solution theory, enabling prediction of micellar composition. Predictions were compared to micelle structures obtained from SANS. A phase diagram was also established.

FINDINGS

The CMCs of these mixtures suggest unusual unfavourable interactions between the two species, despite formation of mixed micelles. Micellar compositions obtained from SANS concurred with those calculated using the averaged interaction parameters for P₂W₁₇-2C_n/C₁₂EO₆ (n = 12 and 14). We attribute the unfavourable interactions to a combination of different phenomena: counterion-mediated interactions between P₂W₁₇ units and the unfolding of the ethylene oxide headgroups of the nonionic surfactant, yet micelles still form in these systems due to the hydrophobic interactions between surfactant tails.

Hybrid Gold Nanoparticle-Polyoxovanadate Matrices: A Novel Surface Enhanced Raman/Surface Enhanced Infrared Spectroscopy Substrate

Bare gold nanoparticles were embedded into an iron-polyoxovanadate matrix and used to enhance both the infrared and Raman signatures of a model analyte. A detailed characterization of the matrix-embedded nanoparticles revealed that they retained a plasmon resonance at 564 nm. The enhancement of vibrational signatures of the model analyte crystal violet using bare and embedded gold nanoparticles was compared for both surface enhanced infrared (SEIRA) spectroscopy and surface enhanced Raman spectroscopy (SERS) yielding enhancement factors of 2.2 for SEIRA and 77 for SERS. In contrast, the bare gold nanoparticles revealed significantly lower enhancements (1.6 for SEIRA; 20 for SERS). Hence, it was shown that embedding nanoparticles within an inorganic polyoxometalate-based matrix is an innovative strategy to amplify their signal enhancement properties in vibrational spectroscopies.

In Situ Synthesis of SERS-Active Au@POM Nanostructures in a Microfluidic Device for Real-Time Detection of Water Pollutants

We present a simple, versatile, and low-cost approach for the preparation of surface-enhanced Raman spectroscopy (SERS)-active regions within a microfluidic channel 50 cm in length. The approach involves the UV-light-driven formation of polyoxometalate-decorated gold nanostructures, Au@POM (POM: H₃PW₁₂O₄₀ (PW) and H₃PMo₁₂O₄₀ (PMo)), that self-assemble in situ on the surface of the polydimethylsiloxane (PDMS) microchannels without any extra functionalization procedure. The fabricated LoCs were characterized by scanning electron microscopy (SEM), UV-vis, Raman, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) techniques. The SERS activity of the resulting Au@POM-coated lab-on-a-chip (LoC) devices was evaluated in both static and flow conditions using rhodamine R6G. The SERS response of Au@PW-based LoCs was found to be superior to Au@PMo counterparts and outstanding when compared to reported data on metal@POM nanocomposites. We demonstrate the potentialities of both Au@POM-coated LoCs as analytical platforms for real-time detection of the organophosphorous pesticide paraoxon-methyl at 10^-6 M concentration level.

Water–gas shift reaction co-catalyzed by polyoxometalate (POM)–gold composites: the “magic” role of POMs

We computationally investigated the WGSR mechanism on POM supported gold and revealed the role of POMs. A direct pathway by formation of COOH_ads from the co-adsorbed H₂O and CO is proposed.

Sonochemical synthesis of polyoxometalate-stabilized gold nanoparticles for point-of-care determination of acetaminophen levels: preclinical study in an animal model

The aim of this study is the accurate and rapid detection of acetaminophen (AP) for point-of-care (POC) clinical diagnosis. Acetaminophen overdose causes acute liver failure and currently there is a lack of rapid quantitative detection methods for this drug in the emergency room. Here, low-frequency sonication (20 kHz) in the presence of phosphomolybdic acid (PMo₁₂) was used to reduce Au³⁺ to Au⁰ and stabilize the resulting spherical Au⁰ nanoparticles (herein AuNPs). These AuNPs@PMo₁₂ were used as nano-probes for the selective detection of acetaminophen in the presence of other commercial drugs. The optical sensing method we describe is based on the aggregation of AuNPs@PMo₁₂ in the presence of acetaminophen, which produces a red-shift in the absorption spectrum of the AuNPs@PMo₁₂, which is characterised by a color change from red to purple that is visible to the naked eye. Furthermore, the quantitative determination of acetaminophen concentrations can be carried out using the eyedropper function in Microsoft's PowerPoint or open access ImageJ software, using RGB (red, green, and blue) values. To prove the feasibility of this novel nanosensor, the concentration of acetaminophen was measured in over-the-counter pharmaceutical tablets and in serum samples taken from mice. This simple sensing approach offers high stability, selectivity, rapid detection time, and cost saving compared to other detection methods, which therefore opens the way for the development of quantitative POC acetaminophen detection using polyoxometalate-stabilized metal nanoparticles.

The aim of this study is the accurate detection of acetaminophen (AP) for point-of-care (POC) clinical diagnosis. The concentration of acetaminophen was measured in over-the-counter pharmaceutical tablets and in serum samples taken from mice.

Light-Triggered Boost of Activity of Catalytic Bola-Type Surfactants by a Plasmonic Metal-Support Interaction Effect

The maximization of activity is a general aim in catalysis research. The possibility for light-triggered enhancement of a catalytic process, even if the process is not photochemical in nature, represents an intriguing concept. Here, we present a novel system for the exploration of the latter idea. A surfactant with a catalytically active head group, a protonated polyoxometalate (POM) cluster, is attached to the surface of a gold nanoparticle (Au NP) using thiol coupling chemistry. The distance of the catalytically active center to the gold surface could be adjusted precisely using surfactants containing hydrocarbon chains (C n) of different lengths ( n = 4-10). Radiation with VIS-light has no effect on the catalytic activity of micellar aggregates of the surfactant. The situation changes, as soon as the surfactants have been attached to the Au NPs. The catalytic activity could almost be doubled. It was proven that the effect is caused by coupling the surface plasmon resonance of the Au NPs with the properties of the POM head group. The improvement of activity could only be observed if the excitation wavelength matches the absorption band of the used Au NPs. Furthermore, the shorter the distance between the POM group and the surface of the NP, the stronger is the effect. This phenomenon was explained by lowering the activation energy of the transition state relevant to the catalytic process by the strong electric fields in the vicinity of the surfaces of plasmonic nanoparticles. Because the catalytic enhancement is wavelength-selective, one can imagine the creation of complex systems in the future, a system of differently sized NPs, each responsible for a different catalytic step and activated by light of different colors.

Magnetic field alignment of stable proton-conducting channels in an electrolyte membrane

Proton exchange membranes with short-pathway through-plane orientated proton conductivity are highly desirable for use in proton exchange membrane fuel cells. Magnetic field is utilized to create oriented structure in proton exchange membranes. Previously, this has only been carried out by proton nonconductive metal oxide-based fillers. Here, under a strong magnetic field, a proton-conducting paramagnetic complex based on ferrocyanide-coordinated polymer and phosphotungstic acid is used to prepare composite membranes with highly conductive through-plane-aligned proton channels. Gratifyingly, this strategy simultaneously overcomes the high water-solubility of phosphotungstic acid in composite membranes, thereby preventing its leaching and the subsequent loss of membrane conductivity. The ferrocyanide groups in the coordinated polymer, via redox cycle, can continuously consume free radicals, thus helping to improve the long-term in situ membrane durability. The composite membranes exhibit outstanding proton conductivity, fuel cell performance and durability, compared with other types of hydrocarbon membranes and industry standard Nafion^® 212.

Proton exchange membranes with short-pathway through-plane proton conductivity are attractive for proton exchange membrane fuel cells. Here the authors align proton conducting channels orthogonal to the plane of composite proton exchange membranes using a magnetic field for improved fuel cell performance.

Keggin Structure, Quō Vādis?

Working under the supervisor of William Lawrence Bragg at the University of Manchester and being under the direct personal and scientific influence by Linus Pauling, Dr. James Fargher Keggin some 85 years ago published a highly unique discovery—the structure of phosphotungstic acid (Nature 1933, 131, 908–909). This structure sparked the reports of other related polyanions from Keggin's contemporaries, marking the true beginnings of structural polyoxometalate chemistry. In this perspective article, we unveil some aspects and applications of Keggin's structure and discuss how it has shaped the course of our understanding of polyoxometalate chemistry and nanomolecular metal oxides/hydroxides in general.

Novel PVP/HTA Hybrids for Multifunctional Rewritable Paper

Owing to its benefits to reducing paper production and consumption, ink-free rewritable paper has attracted great attention and it is desirable to develop rewritable paper based on its low-cost, robust, and environmentally benign color switching systems. Herein, we report the fabrication of a rewritable paper based on novel poly(vinylpyrrolidone)/hexatungstic acid (HTA) hybrids with fast dual-mode color switching. As-prepared rewritable paper shows fast and reversible colorless-blue or blue-colorless color switching upon photo- or hydroprinting, owing to the fast redox transformations of the unique HTA clusters. More interestingly, the rewritable paper can be used as a template for noble-metal reduction and the noble metal can be deposited on the reduced area of the paper to form well-ordered patterns in high resolution. This rewritable paper can be produced in large scale, and the composition can be facilely tuned with various polyoxometalates or polymers. It may not only be an attractive alternative to current paper prints but also be potentially used for noble-metal reduction to prepare photolithographic circuits and optoelectronic devices.

Binary Superlattices from {Mo132} Polyoxometalates and Maghemite Nanocrystals: Long-Range Ordering and Fine-Tuning of Dipole Interactions

In the present article, the successful coassembly of spherical 6.2 nm maghemite (γ-Fe2O3) nanocrystals and giant polyoxometalates (POMs) such as 2.9 nm {Mo132} is demonstrated. To do so, colloidal solutions of oleic acid-capped γ-Fe2O3 and long-chain alkylammonium-encapsulated {Mo132 } dispersed in chloroform are mixed together and supported self-organized binary superlattices are obtained upon the solvent evaporation on immersed substrates. Both electronic microscopy and small angles X-ray scattering data reveal an AB-type structure and an enhanced structuration of the magnetic nanocrystals (MNCs) assembly with POMs in octahedral interstices. Therefore, {Mo132} acts as an efficient binder constituent for improving the nanocrystals ordering in 3D films. Interestingly, in the case of didodecyldimethylammonium (C12)-encapsulated POMs, the long-range ordered binary assemblies are obtained while preserving the nanocrystals magnetic properties due to weak POMs-MNCs interactions. On the other hand, POMs of larger effective diameter can be employed as spacer blocks for MNCs as shown by using {Mo132} capped with dioctadecyldimethylammonium (C18) displaying longer chains. In that case, it is shown that POMs can also be used for fine-tuning the dipolar interactions in γ-Fe2O3 nanocrystal assemblies.

Mechanistic insights into the activation process in electrocatalytic ethanol oxidation by phosphomolybdic acid-stabilised palladium(0) nanoparticles (PdNPs@PMo12)

A Keggin type polyoxometalate (POM), phosphomolybdic acid (PMo₁₂), has been employed to encapsulate and stabilise pseudo-spherical Pd(0) nanoparticles (PdNPs).

In vitro cell cytotoxicity profile and morphological response to polyoxometalate-stabilised gold nanoparticles

Polyoxometalate-stabilised gold nanoparticles internalise in vast quantities into kidney epithelial and skin melanoma cell lines causing antiproliferative action on tumoural cells.

On the formation of gold nanoparticles from [AuIIICl4]− and a non-classical reduced polyoxomolybdate as an electron source: a quantum mechanical modelling and experimental study

DFT calculations and experimental data prove that the [Na{(MoV2O₄)₃(μ₂-O)₃(μ₂-SO₃)₃(μ₆-SO₃)}₂]¹⁵⁻ POM is capable of completely reducing Au(iii) to Au(0).

A polyoxometalate-assisted approach for synthesis of Pd nanoparticles on graphene nanosheets: synergistic behaviour for enhanced electrocatalytic activity

A novel activation step has been applied to the Pd/PMo₁₂/GNSs nanohybrid, which enhances the electrocatalytic activity.

Simple procedure for vacant POM-stabilized palladium (0) nanoparticles in water: structural and dispersive effects of lacunary polyoxometalates

Metallic palladium nanoparticles have been generated by hydrogenation in very mild conditions of aqueous solutions of non-organometallic PdII-derivatives of heteropolytungstates.