Nanoporous Glass Research Articles

Dissolution Manufacturing Strategy for the Facile Synthesis of Nanoporous Metallic Glass Multifunctional Catalyst.

The quest for heightened energy efficiency is inextricably linked to advancements in energy storage and conversion technologies, wherein multifunctional catalysts play a pivotal role by mitigating the slow kinetics endemic to many catalytic reactions. The intricate synthesis and bespoke design of such catalysts, however, present notable challenges. Addressing this, the present study capitalizes on a novel dissolution manufacturing strategy to engineer self-supporting, nanoporous multifunctional electrocatalysts, circumventing the prevalent issue of customizing catalytic functionalities upon demand. This innovative approach grants the flexibility to finely tune the incorporation of active species and metalloid binders, culminating in the creation of a self-supporting nanoporous metal glass electrocatalyst doped with RuO2 (NPMG@RuO2) with outstanding performance in alkaline media. The catalyst showcases superior electrocatalytic activity, achieving low overpotentials of 41.50 mV for the Hydrogen Evolution Reaction and 226.0 mV for Oxygen Evolution Reaction alongside sustained stability over 620 hours.These achievements are attributed to the distinct nanoporous architecture that ensures a high density of catalytic sites and mechanical strength, bolstered by the synergistic interplay between RuO2 and Pt-based metallic glass. The findings provide a versatile template for the development of nanoporous multifunctional catalysts, signifying a leap forward in the realm of energy conversion technologies.

Photo- thermo-induce changes in As2S3- and As2S3: Au-nanoparticles filled porous glass composite: Optics and the molecular structure simulation of the responsible chalcogenide transformations

In this study we continue a more detailed investigation of the photoinduced effect in nanoporous glass impregnated with As2S3 NPs and Au NPs and its influence on the material's optical properties. The goal of this research is establishing the quantum chemical peculiarities of these processes taking into account the impact of gold nanoparticles on the photoinduced structural transformations of As-S component using Raman spectroscopy and theoretically investigating the molecular structure of arsenic sulfide As-S through ab initio quantum chemical calculations. These support the possibility of further variations in optical properties of such composite materials and photo-thermo driven elements made on their basis.

Characterizing the Behavior of Water Interacting with a Nano-Pore Material: A Structural Investigation in Native Environment Using Magnetic Resonance Approaches.

The study of fluid absorption, particularly that of water, into nanoporous materials has garnered increasing attention in the last decades across a broad range of disciplines. However, most investigation approaches to probe such behaviors are limited by characterization conditions and may lead to misinterpretations. In this study, a combined MRI and MAS NMR method was used to study a nanoporous silica glass to acquire information about its structural framework and interactions with confined water in a native humid environment. Specifically, MRI was used for a quantitative analysis of water extent. While MAS NMR techniques provided structural information of silicate materials, including interactive surface area and framework packing. Analysis of water spin-spin relaxation times (T2) suggested differences in water confinement within the characterized framework. Subsequent unsuccessful delivery of paramagnetic molecule into the pores enabled a quantitative assessment of the dimensions that "bottleneck" the pores. Finally, pore sizes were derived from the paramagnetic molecular size, density function theory (DFT) simulation and characterizations on standard samples. Our result matches with Brunauer-Emmett-Teller (BET) analysis that the pore size is less than 1.3 nm. The use of a paramagnetic probe for pore size determination introduces a new approach of characterization in the liquid phase, offering an alternative to the conventional BET analysis that uses gas molecule as probes.

Spatial and Chemical Dual Nano‐Confined Ultrastable Perovskite Quantum Dots Glass Manifesting Exciton Modulation

AbstractNano‐confined synthesis of perovskite quantum dots (QDs) in solid matrix is emerging as a promising route to solve their long‐standing stability problem. Utilizing sol‐gel derived nanoporous glass as matrix that has high flexibility in chemical composition and pore size, a novel spatial and chemical dual nano‐confined strategy is presented for the synthesis of ultrastable perovskite QDs with tunable composition and bandgap in glass. The findings reveal that the Pb─O bonding is formed at perovskite QDs/glass interface during a nano‐confined chemical vapor deposition (CVD) reaction. In particular, the presence of interfacial chemical bonding is discovered to be critical for passivating surface traps and stabilizing the perovskite QDs during the final densification process (related photoluminescence intensity maintained ≈100% after immersed in aqueous solution for 30 days). Series optical spectroscopy unravels the exciton modulation (80 meV) of perovskite QDs in nanoporous and densified glass related to the unique combination of dual physical and chemistry nano‐confined effect. By shedding light on the nano‐confined growth of functional nanocrystals, the research offers the key paths for fabricating high‐performance perovskite devices.

Modeling patchy saturation of fluids in nanoporous media probed by ultrasound and optics.

Nanoporous materials provide high surface area per unit mass and are capable of fluids adsorption. While the measurements of the overall amount of fluid adsorbed by a nanoporous sample are straightforward, probing the spatial distribution of fluids is nontrivial. We consider literature data on adsorption and desorption of fluids in nanoporous glasses reported along with the measurements of ultrasonic wave propagation. We analyze these using the so-called dynamic equivalent medium approach, which is based on Biot's theory of dynamic poroelasticity with coefficients that are continuous random functions of position. When further constrained by optical scattering data for similar systems, the calculations show that on adsorption the characteristic patch size is of the order of 100 pore diameters, while on desorption the patch size is comparable to the sample size. Our analysis suggests that one can employ ultrasound to probe the uniformity of the spatial distribution of fluids in nanoporous materials.

Morphology of nanoporous glass: Stochastic 3D modeling, stereology and the influence of pore width

Excursion sets of Gaussian random fields are used to model the three-dimensional (3D) morphology of differently manufactured porous glasses (PGs), which vary with respect to their mean pore widths measured by mercury intrusion porosimetry. The stochastic 3D model is calibrated by means of volume fractions and two-point coverage probability functions estimated from tomographic image data. Model validation is performed by comparing model realizations and image data in terms of morphological descriptors which are not used for model fitting. For this purpose, we consider mean geodesic tortuosity and constrictivity of the pore space, quantifying the length of the shortest transportation paths and the strength of bottleneck effects, respectively. Additionally, a stereological approach for parameter estimation is presented, i.e., the 3D model is calibrated using merely two-dimensional (2D) cross-sections of the 3D image data. Doing so, on average, a comparable goodness of fit is achieved as well. The variance of the calibrated model parameters is discussed, which is estimated on the basis of randomly chosen, individual 2D cross-sections. Moreover, interpolating between the model parameters calibrated to differently manufactured glasses enables the predictive simulation of virtual but realistic PGs with mean pore widths that have not yet been manufactured. The predictive power is demonstrated by means of cross-validation. Using the presented approach, relationships between parameters of the manufacturing process and descriptors of the resulting morphology of PGs are quantified, which opens possibilities for an efficient optimization of the underlying manufacturing process. Published by the American Physical Society 2024

Facile fabrication of super-slippery and transparent glass with anti-fogging and self-cleaning characteristics

The present work reports a facile and effective approach for developing slippery liquid-infused porous surface (SLIPS) nanoporous glass. Glass was chemically etched using KOH solution followed by silanization and silicone oil coating using vapour deposition at different temperatures. SLIPS glass showed high contact angle ∼ 115⁰ compared to nascent glass (∼40⁰), low hysteresis (<5°). The sample showed sliding angle < 5⁰ against wide range of liquids with surface tension as low as 28 mN/m. The super-slippery behaviour was coupled with uncompromised transparency (>90 %) and enhanced oil retention owing to the presence of nanopores acting as reservoirs. The SLIPS glass maintained slippery nature (SA < 5⁰) during exposure to ultrasonic vibrations, multiple cloth wiping cycles and multiple high-velocity droplet impacts. The slippery glass showed exquisite combination of properties involving anti-fogging, self-cleaning and anti-staining, with widespread applications.

Thermomagnetic instability in superconducting lead-porous glass nanocomposites

In this paper we examine the mechanisms leading to thermomagnetic instability in nanostructured materials and study their regularities. The appearance of thermomagnetic instabilities in the superconducting state of various materials remains one of the problems of applications of superconductors. We studied the temperature and the magnetic field dependences of the magnetization m(T, H) and heat capacity C(T, H) of a nanocomposite consisting of interconnected lead filaments embedded in nanoporous glass (Pb-PG) with filament diameter d = 7 nm. Porous glass contains an arbitrarily orientated multiply connected system of pores of approximately the same size; lead in the nanocomposite forms a replica of the pore system. Thermomagnetic instability was previously observed in this material in superconducting state at T ≤ 5 K on m(H) dependencies in magnetization studies. We established that high enough external heater power P used during the heat capacity measurements in external magnetic field C(H) at T ≤ 5 K can initiate thermomagnetic instability and penetration of magnetic flux into the nanocomposite. The thermomagnetic instability is generally preceded by a sequence of small heat release events with the same magnitude as P. Another sequence of small heat release events is observed in the region close to Hc2. These events are presumably linked to the thermomagnetic instability process and are caused by small redistribution of magnetic flux in the nanocomposite.

Permeability of nanoporous glasses

Permeability of nanoporous glasses

Silanized carbon quantum dots assembled porous glass and its luminescent properties

In this paper, the silanized carbon quantum dots (Si CQDs) were assembled into nano-porous glass (NPG) by solution ultrasonic method. The morphology, structure, elementary composition, luminescence properties, water-resistance and anti-ultraviolet properties were systematically studied. Concentration quenching occurs when the Si CQDs doping content exceeds 7.73 mg/g. It is found that nano-porous glass matrix can effectively disperse and protect the Si CQDs, which realizes the luminescence of Si CQDs in solid state and enhances the fluorescence emission intensity of Si CQDs. In addition, the spatial confinement effect of nano-channels in Si CQDs/NPG composites makes it obtain excellent water-resistance. At the same time, the composites show better photo-stability under continuous UV irradiation. The above results provide a basis for its application in agricultural light conversion films.

Production and biological properties of nano porous glass microparticles for anticancer drug carrier

Nanoporous glass (NPG) microparticles were produced by conventional melt-quenching followed by acid-alkali leaching to get material for anticancer drug carriers. NPG exhibited a positive zeta potential of 34 mV after [3-(2-aminoethylamino) propyl] trimethoxysilane treatment. The specific surface area and the total pore volume of NPG were 47.3 m2/g and 0.692 cm3/g, respectively. The 5-Fluorouracil (5FU) loading capacity of NPG was measured as 18.2 ± 0.2 mg5FU/gNPG. The drug release rate was monitored for 120 hours. To evaluate the cytotoxic effects of NPG on both MCF-7 breast cancer cells and MCF-12A, an immortalized cell line, the study employed the 2,3-bis [2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium5-carboxanilide inner salt (XTT) assay. The XTT results revealed that NPG showed a time and concentration-dependent cytotoxic effect. It is anticipated that NPG is a safe and effective material for drug delivery systems for in vitro and a promising alternative material for in vivo applications.

Functionalisation of alkali-resistant nanoporous glass via Au nanoparticle decoration using alkaline impregnation: catalytic activity for CO removal.

The concerted use of nano-metal particles with catalytic functions and nanoporous materials holds promise for effective air purification and gas sensing; however, only a few studies have used porous glasses as supports for Au nanoparticles. Furthermore, Au/nanoporous glasses with activities comparable to that of Au/TiO2, which is a typical Au catalyst, have not been reported to date. This study demonstrates that a nanoporous glass, which is highly acid- and alkali-resistant and chemically stable, can be decorated with Au nanoparticles using an alkali impregnation method. The resulting composite exhibits high catalytic activity in CO oxidation. The catalysts reported herein are as active as Au/TiO2 catalysts per active site. Further optimisation of the pore properties of the glass and sizes of the Au nanoparticles is expected to result in excellent catalytic systems for CO removal and sensing.

Nanoporous glass as prospective material for fiber optics

The method of manufacturing active silica fibers by sintering nanoporous glasses has a number of advantages over methods of vapor deposition (MCVD, OVD). The features of obtaining nanoporous glasses by the method of two-phase separation of alkali borosilicate glasses are described. Examples of doping sintered nanoporous glasses with rare earth elements are given and the main results on the production of active fibers with a core are considered. It has been shown that such fibers are similar to their MCVD analogues in terms of properties. At the same time, it is possible to impregnate nanoporous glass with large (more than 1 at.%) concentration of dopants without revealing clustering effects and without noticeable fluctuations in the refractive index of the fiber core glass.

Radiation response properties of organic−inorganic perovskite-type compounds in a nanoporous glass

Abstract We fabricated hybrid composites, where various organic–inorganic layered perovskite-type compounds (C6H5C2H4NH3)2PbBr4, (C6H5CH2NH3)2PbBr4, and (C4H9NH3)2PbBr4 were incorporated into a nanoporous glass, and their photoluminescence and scintillation properties were investigated for fast scintillator applications. A photoluminescence peak derived from free excitons was observed at around 410 nm for all the samples. Furthermore, a sharp scintillation peak originating from excitons was detected from the hybrid composites with (C6H5C2H4NH3)2PbBr4 or (C6H5CH2NH3)2PbBr4, and the hybrid composite with (C6H5C2H4NH3)2PbBr4 showed the highest scintillation intensity. In addition, afterglow levels of the fabricated hybrid composites were 430–620 ppm, and the values were higher than that of a (C6H5C2H4NH3)2PbBr4 single crystal.

Ligament rotation-dominated creep in stochastic bicontinuous nanoporous metallic glass

Bicontinuous nanoporous metallic glasses (BNPMGs) are promising candidates in functional applications such as energy storage, sensors, and fuel cells. The time-dependent deformation strongly affects their long-term in-service performance. This study investigates the tensile creep behavior and its underlying deformation mechanisms of Cu50Zr50 BNPMGs through molecular dynamics simulations. The creep-recovery fatigue behavior is revealed. Our results manifest that both the transient and steady creep strengths increase with the solid fraction. The transient strength is larger for smaller ligament sizes, but the steady creep strength has very mild sensitivity to the ligament size. The generalized Kelvin model, consisting of two Kelvin units and one Maxwell unit connected in series, can accurately predict the creep and recovery curves. The rotation of individual ligaments, rather than atomic diffusion, is the dominant creep mechanism. During creep, the shear transformation zones are mainly developed on the ligament surface, and the strain in the ligament core is relatively smaller. The creep stress exponent has no definite relation with the creep mechanism and decreases with the increasing solid fraction. With the increase in the creep-recovery cycle number, the creep rate decreases, and the recovery procedure makes a milder impact on the creep response.

Luminescent Properties of Composite Materials Based on Porous Glasses Activated by Silver and Lanthanum

Composite materials (CMs) based on matrices of high-silica nanoporous glasses activated by silver and lanthanum are synthesized. It is established that, depending on the composition, the CM samples exhibit luminescence in the UV, violet-blue, green, red, and infrared spectral ranges due to the presence of isolated Ag+-ions, Ag+–Ag+ paired centers, molecular clusters (MCs) and nanoparticles (NPs) of silver, and oxygen vacancies in La2O3, together with various silicon defect centers.

Additive Manufacturing of Transparent Multi-Component Nanoporous Glasses.

Fabrication of glass with complex geocd the low resolution of particle-based or fused glass technologies. Herein, a high-resolution 3D printing of transparent nanoporous glass is presented, by the combination of transparent photo-curable sol-gel printing compositions and digital light processing (DLP) technology. Multi-component glass, including binary (Al2 O3 -SiO2 ), ternary (ZnO-Al2 O3 -SiO2 , TiO2 -Al2 O3 -SiO2 ), and quaternary oxide (CaO-P2 O5 -Al2 O3 -SiO2 ) nanoporous glass objects with complex shapes, high spatial resolutions, and multi-oxide chemical compositions are fabricated, by DLP printing and subsequent sintering process. The uniform nanopores of Al2 O3 -SiO2 -based nanoporous glasses with the diameter (≈6.04nm), which is much smaller than the visible light wavelength, result in high transmittance (>95%) at the visible range. The high surface area of printed glass objectives allows post-functionalization via the adsorption of functional guest molecules. The photoluminescence and hydrophobic modification of 3D printed glass objectives are successfully demonstrated. This work extends the scope of 3D printing to transparent nanoporous glasses with complex geometry and facile functionalization, making them available for a wide range of applications.

Fracture toughness and destructive mechanism of ductile nanoporous metallic glass and its crystal-impregnated nanocomposite

Fracture toughness and destructive mechanism of ductile nanoporous metallic glass and its crystal-impregnated nanocomposite

Femtosecond Laser Fabrication of Silver Microstructures in Nanoporous Glasses

This paper presents the results of studying the process of laser formation of microstructures from silver nanoparticles in nanoporous quartz glasses. Glass samples were impregnated with organometallic molecules Ag(hfac)COD in a supercritical carbon dioxide environment. The formation of point and linear microstructures was carried out by high-frequency (70 MHz) femtosecond laser radiation with a wavelength of 525 nm and energy in the pulse up to 1 nJ. It was found that the formation of microstructures occurs due to photo- and thermal decomposition of precursor molecules with the formation of plasmonic silver nanoparticles. It is shown that the developed temperatures can exceed the melting point of glass, which leads to the appearance of microstructures with altered refractive index. A qualitative model explaining the individual stages of cluster formation in the glass volume under point laser impact is presented.

Correction: Femtosecond laser inscription of polarized-sensitive volume phase grating in nanoporous glass

Correction: Femtosecond laser inscription of polarized-sensitive volume phase grating in nanoporous glass