Search Results (69)

Phenolic aerogel holds great promise for applications in thermal protection against ablation, and constructing inorganic–organic hybrid networks is an effective strategy to enhance its oxidation and ablation resistance. This study introduces a stepwise hybridization strategy for the preparation of SiO₂–ZrO₂–phenolic resin aerogels (SZPA). First, nano-silica sol and nanometer-scale zirconia were physically blended to form a uniformly dispersed mixture. Subsequently, the modified silica was incorporated into a phenolic resin solution to construct a three-dimensional hybrid silica–phenolic network framework. Nano-sized zirconia was then uniformly dispersed within the matrix as a physical reinforcing phase through high-shear dispersion. Finally, the SZPA with a hierarchical nanoporous structure was obtained via ambient-pressure drying. Owing to its unique hybrid network structure, the aerogel exhibits markedly improved properties: the thermal conductivity is as low as 0.0419–0.0431 W/(m·K) (a reduction of approximately 24%), and the specific surface area is as high as 190–232 m²/g (an increase of approximately 83%). Meanwhile, the inorganic network considerably enhances the residual mass at elevated temperatures, as well as the oxidation resistance and thermal stability of the matrix. Among the tested materials, the SZPA-4 exhibited outstanding thermal insulation capability at high temperatures; its back surface temperature reached only 74.4 °C after 600 s of exposure to a 1200 °C butane flame. This study provides a feasible route for the preparation of high-performance phenolic-based composite aerogels for aerospace thermal protection systems, thereby expanding their potential applications in extreme thermal environments. Full article

Silicon carbide (SiC) has attracted increasing attention as a robust photoelectrode material for solar water splitting due to its exceptional chemical stability, mechanical strength, and resistance to photocorrosion. Recent advances in nanostructuring—particularly the development of nanoporous SiC architectures—have dramatically improved light absorption, charge separation, and charge transport in this material. This review summarizes current strategies to enhance the PEC performance of SiC, including hierarchical nanostructuring, defect engineering (e.g., doping to tailor band structure), heterojunction formation with co-catalysts, and incorporation of plasmonic nanoparticles. Remaining challenges are discussed, notably the wide band gap of common SiC polytypes (limiting visible-light utilization) and rapid charge-carrier recombination. In addition, we examine the techno-economic prospects for SiC-based PEC systems, outlining the efficiency and durability benchmarks required for commercial hydrogen production. Finally, we propose future research directions to achieve efficient, durable SiC photoelectrodes and to guide the development of scalable PEC water-splitting devices. This review uniquely integrates material design strategies with techno-economic evaluation, providing a roadmap for SiC-based PEC systems. Full article

Bionic synthesis technology has made significant breakthroughs in porous functional materials by replicating and optimizing biological structures. For instance, biomimetic titanium dioxide-coated carbon multilayer materials, prepared via biological templating, exhibit a hierarchical structure, abundant nanopores, and synergistic effects. Bionic mineralization further enhances microcapsules by forming a secondary inorganic wall, granting them superior impermeability, high elastic modulus, and hardness. Through techniques like molecular self-assembly, electrospinning, and pressure-driven fusion, researchers have successfully fabricated centimeter-scale artificial lamellar bones without synthetic polymers. In environmental applications, electrospun membranes inspired by lotus leaves and bird bones achieve 99.94% separation efficiency for n-hexane–water mixtures, retaining nearly 99% efficiency after 20 cycles. For energy applications, an all-ceramic silica nanofiber aerogel with a bionic blind bristle structure demonstrates ultralow thermal conductivity (0.0232–0.0643 W·m⁻¹·K⁻¹) across a broad temperature range (−50 to 800 °C). This review highlights the preparation methods and recent advances in biomimetic porous materials for practical applications. Full article

As an efficient clean energy technology, water electrolysis for hydrogen production has its efficiency limited by the sluggish oxygen evolution reaction (OER) kinetics, which drives the demand for the development of high-performance anode OER catalysts. This work constructs bimetallic (Al, Mn) co-doped nanoporous spinel CoFe₂O₄ (np-CFO) with a tunable structure and composition as an OER catalyst through a simple two-step dealloying strategy. The as-formed np-CFO (Al and Mn) features a hierarchical flaky configuration; that is, there are a large number of fine nanosheets attached to the surface of a regular micron-sized flake, which not only increases the number of active sites but also enhances mass transport efficiency. Consequently, the optimized catalyst exhibits a low OER overpotential of only 320 mV at a current density of 10 mA cm⁻², a minimal Tafel slope of 45.09 mV dec⁻¹, and exceptional durability. Even under industrial conditions (6 M KOH, 60 °C), it only needs 1.83 V to achieve a current density of 500 mA cm⁻² and can maintain good stability for approximately 100 h at this high current density. Theoretical simulations indicate that Al and Mn co-doping could indeed optimize the electronic structure of CFO and thus decrease the energy barrier of OER to 1.35 eV. This work offers a practical approach towards synthesizing efficient and stable OER catalysts. Full article

A superhydrophobic surface with hierarchical micro/nano-array structures was successfully fabricated on 6061 aluminum alloy through a combination of femtosecond laser etching and anodic oxidation. Femtosecond laser etching formed a regularly arranged microscale “pit-protrusion” array on the aluminum alloy surface. After modification with a fluorosilane ethanol solution, the surface exhibited superhydrophobicity with a contact angle of 154°. Subsequently, the anodic oxidation process formed an anodic oxide film dominated by an array of aluminum oxide (Al₂O₃) nanopores at the submicron scale. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses revealed that the nanopore structures uniformly and continuously covered the laser-ablated layer. This hierarchical structure significantly increased the surface water contact angle to 162°. Wettability analysis showed that the prepared composite coating formed an air layer accounting for 91% of the surface area. Compared with the sample only treated by femtosecond laser etching, the presence of the Al₂O₃ nanopore structure significantly enhanced the mechanical durability, superhydrophobic durability, and corrosion resistance of the superhydrophobic surface. The proposed multi-step fabrication strategy offers an innovative method for creating multifunctional, durable superhydrophobic coatings and has important implications for their large-scale industrial use. Full article

This work introduces a new type of water evaporation-driven nanogenerator (S-WEG) utilizing the natural mineral sepiolite, which capitalizes on its hierarchical nanoporous architecture and intrinsic hydrophilicity to harvest energy from ambient humidity through capillary-driven evaporation. The S-WEG, fabricated via a facile drop-coating drying method, demonstrates remarkable mechanical flexibility and sustained operational reliability. Our results demonstrate that by optimizing evaporation height and width, the S-WEG can generate a short-circuit current of ~0.6 μA and an open-circuit voltage of ~0.9 V. Through series and parallel configurations of multiple S-WEG units, the current and voltage outputs can be effectively amplified to power small-scale electronics. Full article

Traditional β-eucryptite (LiAlSiO₄) is renowned for its unique characteristics of low thermal expansion and high temperature thermal stability, making it an ideal material for precision instruments and aerospace applications. In this study, β-eucryptite was fabricated into an aerogel structure through the sol–gel process and supercritical drying method and using alumina sol as a cost-effective precursor. The synthesized β-eucryptite aerogel demonstrated unique properties including a negative thermal expansion coefficient (−7.85 × 10⁻⁶ K⁻¹), low density (0.60 g/cm³), and high specific surface area (18.1 m²/g). X-ray diffraction (XRD) and transmission electron microscopy (TEM) mutually corroborated the crystalline structure of β-eucryptite, with XRD confirming the phase purity and TEM imaging revealing well-defined crystal lattice characteristics. Combined nitrogen adsorption–desorption analysis and scanning electron microscopy observations supported the hierarchical porous microstructure, with SEM visualizing interconnected nanoporous networks and nitrogen sorption data verifying the porosity. The negative thermal expansion behavior was directly linked to the β-eucryptite crystal structure, as collectively validated by thermal expansion measurements. Additionally, Fourier transform infrared spectroscopy (FTIR) independently confirmed the aluminosilicate framework structure through characteristic vibrational modes. This research shows the innovation in the synthesis of β-eucryptite aerogel, especially its application potential in precision instruments and building materials that need low thermal expansion and high stability, and the use of aluminum sol as an aluminum source has simplified the preparation steps and reduced production costs. Full article

Pd-WO₃ coatings on porous silicon (PSi) substrates are engineered to enhance interfacial charge transfer and surface reactivity through atomic-scale structural tailoring. This study combines first-principles calculations and experimental characterization to elucidate how Pd nanoparticles (NPs) optimize the coating’s electronic structure and environmental stability. The hierarchical PSi framework with uniform nanopores (200–500 nm) serves as a robust substrate for WO₃ nanorod growth (50–100 nm diameter), while Pd decoration (15%–20% surface coverage) strengthens Pd–O–W interfacial bonds, amplifying electron density at the Fermi level by 2.22-fold. Systematic computational analysis reveals that Pd-induced d-p orbital hybridization near the Fermi level (−2 to +1 eV) enhances charge delocalization, optimizing interfacial charge transfer. Experimentally, these modifications enhance the coating’s response to environmental degradation, showing less than 3% performance decay over 30 days under cyclic humidity (45 ± 3% RH). Although designed for gas sensing, the coating’s high surface-to-volume ratio and delocalized charge transport channels demonstrate broader applicability in catalytic and high-stress environments. This work provides a paradigm for designing multifunctional coatings through synergistic interface engineering. Full article

Cave environments represent extreme and underexplored ecosystems wherein fungi play a crucial role in nutrient cycling and ecological dynamics. This study provides the first comprehensive assessment of fungal diversity in air samples from caves across Portugal, with six samples from five locations being assessed through culture-dependent and metabarcoding approaches. From the five bat roosts studied, eleven morphologically distinct fungal colonies were isolated, with genera such as Aspergillus, Penicillium, and Chaetomium identified. Concurrently, Oxford Nanopore sequencing of the internal transcribed spacer (ITS) region of fungal rDNA revealed 286 genera, with Aspergillus, Candida, and Calyptella dominating across the sites. Diversity indices and community composition analyses, including Principal Coordinate Analysis (PCoA) and hierarchical clustering, highlighted distinct fungal profiles influenced by site-specific environmental factors and human activity. The data underscores the dual role of fungi in bat roosts as essential decomposers, emphasizing their adaptability to oligotrophic conditions. These findings advance our understanding of subterranean fungal ecology and emphasize the need for targeted conservation efforts to protect cave ecosystems from anthropogenic impacts. Full article

The spherical nanoindentation macroscopic stress–macroscopic strain relationship of hierarchical honeycomb nanoporous material is defined by combining the spherical nanoindentation simulation and the uniaxial compression simulation. At the same time, the macroscopic elastic modulus and the macroscopic yielding stress of the hierarchical material are obtained from the curves through different methods. The results show that the macroscopic stress–macroscopic strain curve of the hierarchical nanoporous materials nanoindented to a depth of 30 nm is basically consistent with the curve of the hierarchical nanoporous materials when uniaxially compressed down to 25 nm. Through the nanoindentation and uniaxial compression, the macroscopic elastic moduli and the macroscopic yielding stresses are also close to the scale formula. Full article

Developing cost-effective and high-performance non-precious metal-based electrocatalysts for hydrogen evolution reaction is of crucial importance toward sustainable hydrogen energy systems. Herein, we prepare a novel hybrid electrode featuring intermetallic Fe₂Mo nanoparticles anchored on the hierarchical nanoporous copper skeleton as robust hydrogen evolution electrocatalyst by simple and scalable alloying and dealloying methods. By virtue of the highly active intermetallic Fe₂Mo nanoparticles and unique bicontinuous nanoporous copper skeleton facilitating ion/molecule transportation, nanoporous Fe₂Mo/Cu electrode shows excellent hydrogen evolution reaction electrocatalysis, with a low Tafel slope (~71 mV dec⁻¹) to realize ampere-level current density of 1 A cm⁻² at a low overpotential of ~200 mV in 1 M KOH electrolyte. Furthermore, nanoporous Fe₂Mo/Cu electrode exhibits long−term stability exceeding 400 h to maintain ~250 mA cm⁻² at an overpotential of 150 mV. Such outstanding electrocatalytic performance enables the nanoporous Fe₂Mo/Cu electrode to be an attractive hydrogen evolution reaction catalyst for water splitting in the hydrogen economy. Full article

Electrochemical glucose sensing is vital for biomedical applications, particularly in diabetes management and continuous health monitoring. Among electrochemical sensors, non-enzyme-based sensors offer advantages such as cost-effectiveness, robust anti-interference capabilities, and environmental stability compared to enzyme-based ones. This study focuses on the development of non-enzyme-based glucose sensors utilizing hierarchical nanostructured copper (Cu) electrodes. The electrodes are fabricated by selectively dissolving components from an alloy precursor. Specifically, MnCu alloy ribbons prepared by melt rolling were used due to their favorable properties, and electrochemical dealloying was employed to create nanostructured Cu with high electrocatalytic activity for glucose oxidation. Three-dimensional bicontinuous nanoporous copper with an average pore size of 34 nm~86 nm and an average ligament size range of 45 nm~125 nm can be obtained. The optimized hierarchical nanostructured Cu electrodes exhibited excellent performance, including high sensitivity (0.652 mA·mM⁻¹·cm⁻²), a wide linear detection range (0.001 mM to 1.5 mM), a low detection limit (0.73 μM), and a rapid response time. This work demonstrates the potential of nanostructured Cu in the advancement of non-enzyme-based glucose sensors. Full article

Nanoporous copper (np-Cu) has attracted much more attention due to its lower cost compared to other noble metals and high functionality in practical use. Herein, Al_100−xCu_x(x = 13–88 at.%) precursor films with thicknesses of 0.16–1.1 μm were fabricated by varying magnetron co-sputtering parameters. Subsequently, utilizing a one-step dealloying strategy, a series of np-Cu films with ligament sizes ranging from 11.4–19.0 nm were synthesized. The effects of precursor composition and substrate temperature on the microstructure of np-Cu films were investigated. As the atomic ratio of Cu increases from 15 to 34, the np-Cu film detached from the substrate gradually transforms into a bi-continuous ligament-channel structure that is well bonded to the substrate. Furthermore, the novel bi-layer hierarchical np-Cu films were successfully prepared based on single-layer nanoporous films. Our findings not only contribute to the systematic understanding of the modification of the morphology and structure of np-Cu films but also offer a valuable framework for the design and fabrication of other non-noble nanoporous metals with tailored properties. Full article

With the growing demand for new energy sources, electrochemical water splitting for hydrogen production is a technology that must be vigorously promoted. Therefore, to improve the efficiency of the oxygen evolution reaction (OER) at the anode, high-performance OER catalysts are essential. Given their advantages in electrocatalysis, nanoporous materials have garnered considerable attention in previous studies for OER applications. This review provides a comprehensive overview of various strategies to optimize active site utilization in nanoporous materials. These strategies include regulating pore size and porosity, constructing hierarchical nanoporous structures, and enhancing material conductivity. Additionally, it covers approaches to boost the intrinsic OER activity of nanoporous materials, such as tuning the composition of anions and cations, creating vacancies, constructing interfaces, and forming boundary active sites. While nanoporous materials offer significant potential for advancing OER, challenges remain, including difficulties in quantifying activity within nanopores, the unclear impact of nanoporous material morphology, challenges in accessing nanopore interiors with in situ techniques, and a lack of theoretical calculations on pore structure. However, these challenges also present opportunities, and we hope this review provides a fresh perspective to inspire future research. Full article

Anodized aluminum oxide (AAO) molds were used for the production of large-area and inexpensive superhydrophobic polymer films. A controlled anodization methodology was developed for the fabrication of hierarchical micro–nanoporous (HMN) AAO imprint molds (HMN-AAO), where phosphoric acid was used as both an electrolyte and a widening agent. Heat generated upon repetitive high-voltage (195 V) anodization steps is effectively dissipated by establishing a cooling channel. On the HMN-AAO, within the hemispherical micropores, arrays of hexagonal nanopores are formed. The diameter and depth of the micro- and nanopores are 18/8 and 0.3/1.25 µm, respectively. The gradual removal of micropatterns during etching in both the vertical and horizontal directions is crucial for fabricating HMN-AAO with a high aspect ratio. HMN-AAO rendered polycarbonate (PC) and polymethyl methacrylate (PMMA) films with respective water contact angles (WCAs) of 153° and 151°, respectively. The increase in the WCA is 80% for PC (85°) and 89% for PMMA (80°). On the PC and PMMA films, mechanically robust arrays of nanopillars are observed within the hemispherical micropillars. The micro–nanopillars on these polymer films are mechanically robust and durable. Regular nanoporous AAO molds resulted in only a hydrophobic polymer film (WCA = 113–118°). Collectively, the phosphoric acid-based controlled anodization strategy can be effectively utilized for the manufacturing of HMN-AAO molds and roll-to-roll production of durable superhydrophobic surfaces. Full article