Search Results (585)

A lightweight and high-efficiency microwave-absorbing material was developed via an in situ solvothermal pyrolysis strategy by anchoring sphere-like Fe₃O₄ nanostructures onto bamboo-derived porous carbon (BPC). The resulting composites preserve the intrinsic anisotropic honeycomb architecture of bamboo while introducing uniformly distributed magnetic nanoparticles, enabling synergistic dielectric–magnetic loss. Electromagnetic parameters, alongside impedance matching, were successfully modulated through the optimization of precursor concentrations. Of the evaluated materials, BPC-0.9 stood out for its intense attenuation, recording an RL_min of −45.17 dB at a 1.8 mm thickness. Furthermore, a significant effective absorption bandwidth of 6.65 GHz was attained by the BPC-0.6 sample at only 2.2 mm. Several factors contribute to the boosted efficiency, starting with conductive and interfacial polarization losses paired with multiple scattering events. Furthermore, magnetic loss components, encompassing eddy current effects as well as natural and exchange resonances, play a pivotal role in optimizing the material’s response. Furthermore, radar cross-section (RCS) modeling reveals a substantial reduction of 19.9 dB·m², verifying the material’s viability for real-world stealth technologies. Our findings offer a straightforward methodology for fabricating magnetic carbon structures from biomass with adjustable dielectric responses, underscoring their potential in high-performance energy conversion and low-density microwave absorption. Full article

Prussian blue (PB) nanocubes have been explored as promising cathode materials for high-performance sodium-ion (SIBs) and lithium-ion batteries (LIBs). These nanostructures exhibit good cycling stability and electrochemical resilience. They are synthesized through a co-precipitation method followed by vacuum drying, resulting in a porous and conductive nanocube framework. This architecture facilitates efficient ion diffusion, enhanced electrolyte accessibility, and effective mitigation of volume changes during cycling. In SIB applications, the PB nanocubes maintain stable performance over 300 and 400 cycles at current densities of 0.05 and 0.1 A g⁻¹, respectively, and deliver a capacity of 26.2 mAh g⁻¹ at 2.0 A g⁻¹. For LIBs, they exhibit sustained cycling over 200 and 300 cycles under similar conditions, with a capacity of 20.2 mAh g⁻¹ at 2.0 A g⁻¹. These findings underscore the structural benefits of PB nanocubes for dual-ion battery systems. Full article

Self-sustained metal aerogels are emerging as advanced porous materials with a 3D network of nanostructures that are exclusively made of metals. Metal aerogels possess a distinctive combination of metallic nanoparticles with excellent electronic conductivity, and the excellent porosity of the aerogels allows the extensive exposure of electrocatalytic active sites, together with remarkable mass transport networks in a single entity, unlocking widespread application potential ranging from energy storage and conversion to environmental remediation. In this review, we systematically examine the potential of metal aerogels as electrocatalysts for ethanol electro-oxidation. Various synthesis routes, structure–property relationships, and their function as anode electrocatalysts have been critically reviewed. Due to their 3D porous metallic nature, noble metal aerogel catalysts were found to exhibit excellent ethanol oxidation currents, anti-poisoning for reaction intermediates, high mass, and specific activities of 5–20 times those of traditional Pd/C catalysts. In conclusion, it is shown that metal aerogel catalysts exhibit enhanced activity for ethanol electro-oxidation currents over traditional Pd/C catalysts. Despite this, several challenges exist in realizing the commercial applications of metal aerogels, which have been clearly and elaborately stated as future perspectives and research directions in the field of metal aerogel electrocatalysis. Full article

This work reports on the synthesis and electrochemical investigation of sustainable carbon–TiO₂ nanocomposites derived from marine biowaste, designed to elucidate light-assisted charge storage mechanisms in non-aqueous electrolytes. Porous carbons obtained from prawn chitin and blue shark gelatin were decorated in situ with TiO₂ nanoparticles using a deep eutectic solvent (DES) as a green synthesis medium. Structural and morphological characterisation revealed that TiO₂ incorporation induces significant nanoscale reorganisation of the carbon framework, resulting in hierarchical porosity, increased surface area, and intimate semiconductor–carbon interfaces. Electrochemical evaluation in a three-electrode configuration using an ethaline-based DES electrolyte demonstrated that TiO₂ decoration substantially enhances capacitive performance and cycling stability, with the prawn chitin-derived composite achieving a specific capacitance of 54 ± 3 F g⁻¹ and 91% retention after 10,000 cycles. Under illumination, all TiO₂-containing composites exhibited a pronounced increase in anodic current response and discharge time, indicating photo-assisted surface charge accumulation. Although the absolute capacitance values are modest compared to those of aqueous supercapacitor systems, the results provide mechanistic insight into the interplay among nanostructure, semiconductor photoactivity, and ion transport in viscous, hydrogen-bonded DES electrolytes. By combining waste-derived carbons, green synthesis routes, and photo-responsive nanostructures, this study highlights a sustainable strategy for developing multifunctional carbon-based nanomaterials with light-modulated electrochemical behaviour. Full article

To improve the rutting resistance and low-temperature cracking performance of polymer-modified asphalt under extreme conditions, hierarchically structured ZnO-loaded porous activated carbon (ZnO/PAC) nanosheets were introduced as a synergistic reinforcing agent for SBS-modified asphalt. The ZnO/PAC hybrids were synthesized via template-assisted carbonization followed by hydrothermal growth, and their effects were evaluated by microscopic characterization and rheological tests, including temperature sweeps, multiple stress creep and recovery (MSCR), and bending beam rheometer (BBR) analyses. ZnO was successfully anchored onto the PAC, forming a three-dimensional flower-like nanostructure. Among the investigated samples, ZPS3 with 3 wt.% ZnO/PAC showed the best overall performance. At 64 °C, the rutting factor increased from 4.2 kPa for the SBS-modified asphalt to 6.8 kPa for ZPS3, representing a ~62% enhancement and indicating markedly improved high-temperature deformation resistance. MSCR results further confirmed the superior rutting resistance of ZPS3, which exhibited the highest recovery and the lowest non-recoverable creep compliance. In addition, BBR results showed that the low-temperature performance grade improved from −12 °C for conventional the SBS-modified asphalt to −18 °C for the ZnO/PAC-modified system. These results demonstrate that ZnO/PAC nanosheets can effectively enhance both the high-temperature rutting resistance and low-temperature cracking resistance of SBS-modified asphalt. Full article

Porous thin-film getters are extensively utilized in the field of MEMS vacuum packaging. Nevertheless, their effectiveness is frequently constrained by the comparatively modest effective surface area of conventional planar structures. In this work, a porous Au/Ti thin-film getter based on a three-dimensional black silicon scaffold is developed to enhance the effective surface area and improve gettering performance. The fabrication of black silicon nanostructures is achieved through an SF₆/O₂-based inductively coupled plasma (ICP) etching process, followed by the deposition of Au/Ti bilayer films by DC magnetron sputtering. The morphological evolution of the Ti film on the nanostructured substrate and the activation behavior of the Au/Ti bilayer are systematically investigated using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results demonstrate that the shadowing effect during sputtering leads to the formation of a porous film with increased surface roughness and an open structure. XPS analysis demonstrates that there is a significant increase in the oxygen content on the surface at higher activation temperatures. This suggests that effective sorption capability is achieved following activation. In comparison with planar substrates, the three-dimensional black silicon scaffold has been demonstrated to promote the formation of a more open and functional structure. The results obtained from this study indicate that the proposed fabrication strategy offers a feasible and MEMS-compatible approach for the construction of porous thin-film getters, thereby enhancing their effective surface area. Full article

Water electrolysis has emerged as a strategically appealing route for the sustainable production of green hydrogen (H₂) via the hydrogen evolution reaction (HER), though the sluggish kinetics of the oxygen evolution reaction (OER) remains a bottleneck hindering large-scale practical applications. In this regard, an attractive solution is offered by the integration of the ethanol oxidation reaction (EOR) into hybrid water-splitting systems, favorably reducing anodic overpotentials. Nonetheless, an open challenge is related to the fabrication of eco-friendly and economically viable catalysts free from noble metals, combining efficiency and stability. Herein, we explore nickel-oxide-based nanostructures grown onto porous Ni foam scaffolds by a scalable hydrothermal (HT) approach as EOR electrocatalysts. Material properties arising from modulation of the sole HT growth time are investigated by complementary structural, microscopic, and spectroscopic techniques. Electrochemical tests demonstrate good durability and very attractive EOR performances, mainly influenced by the morphology and the NiOOH surface content of the target systems. Overall, the present work advances an attractive route to transition-metal-based electrocatalysts for efficient alcohol-oxidation-assisted water electrolysis. Full article

Redox-flow batteries are a promising emerging technology for large-scale storage of renewable energy. However, existing ion-exchange membranes used for separating electrolytes are expensive and often ineffective at preventing crossover of redox-active species, leading to a decrease in battery capacity over time. Herein, we introduce a new class of proton-conducting membranes formed by depositing highly alkylated waxy hydrophobic salts on porous polypropylene supports and demonstrate that they form self-assembled nanostructures which exclusively conduct protons via a unique mechanism of action. These new “ionowax” membranes display comparable proton conductivities to existing commercially available functionalized porous polymer membranes but are cheaper and easier to fabricate. We anticipate that these new membranes will facilitate future development of cheaper and/or longer-lasting aqueous redox-flow batteries. Full article

In this study, composite silica-containing nanostructures were biosynthesized from residual rice husk through a fermentative process using Aspergillus niger at room temperature without calcination. The obtained nanostructures were initially characterized by UV–Vis spectrophotometry, Fourier-transform infrared spectroscopy (FTIR), and field-emission scanning electron microscopy (FE-SEM) to determine their optical and structural properties compared with chemically synthesized silica. The results demonstrated the successful formation of composite silica-containing amorphous nanostructures under ambient conditions without the use of calcination or mineral acids. UV–Vis analysis revealed intense absorption in the deep ultraviolet region, attributed to electronic transitions associated with Si–O–Si bonds within the amorphous silica network. FTIR analysis enabled the identification of functional groups present on the material surface, providing direct evidence of the nanostructures’ chemical composition. Additionally, FE-SEM micrographs showed that the rice husk surface after biosynthesis exhibited a rough and porous texture with a morphology consistent with the formation of composite silica-containing amorphous nanostructures, in agreement with the characteristic Si–O–Si vibrational bands observed in the FTIR spectra and the strong ultraviolet absorption detected by UV–Vis analysis. Full article

The transformation of waste plastics into hydrogen and functional carbon (C) materials represents a promising pathway for achieving both resource recycling and the production of value-added products. Owing to their tunable physicochemical properties, plastic-derived carbons have attracted significant attention in electrochemical energy storage applications. Various C nanostructures, including graphene, porous C, hard C, and C nanotubes (CNTs), can be generated from discarded plastics through thermochemical processes. The electrochemical performance of these materials is closely governed by their structural characteristics, such as pore architecture, specific surface area, heteroatom doping, surface functionalities, and dimensional morphology. This review aims to provide a comprehensive and systematic overview of the conversion of waste plastics into functional C nanomaterials via thermochemical routes, particularly catalytic pyrolysis and carbonization. The resulting C nanostructures are systematically categorized based on their dimensional architectures (0D, 1D, 2D, and 3D) and comparatively analyzed in terms of their structural features and electrochemical performance. Emphasis is placed on the transformation of diverse plastic feedstocks into high-value C materials with tailored dimensional architectures, including graphene, CNTs, C nanospheres, C nanosheets, porous carbons, and their composites. Furthermore, recent progress and critical challenges in utilizing these materials for electrochemical energy storage systems, such as supercapacitors and rechargeable batteries (Li-ion, Na-ion, K-ion, Li-S, and Zn-air), are discussed. Distinct from previous reports, this review highlights the correlation between thermochemical processing strategies, resulting structural features, and electrochemical performance, providing new insights into the rational design of high-performance C materials. These findings are expected to facilitate the advancement of sustainable energy storage technologies while contributing to effective plastic waste valorization. Full article

In this work, we report the fabrication of SnO₂-based composite nanostructures in view of their application as a sensor element toward N₂O gas exposure. The samples were produced by laser ablation of a composite SnO₂-TiO₂ target performed in air at atmospheric pressure (in open air). We examined how the structure, morphology, composition, and physical properties of the samples change with the TiO₂ content being introduced into the SnO₂ target. The laser ablation of SnO₂-based targets in open air produced samples with a structure in which SnO₂ and SnO crystal phases co-existed, as the crystal phases were distinguished in separate nanoparticles. The nanoparticles formed a complex porous structure with oxygen-related defects. We investigated the gas-sensing properties of composite SnO₂-based sensor elements working under UV irradiation. The highest response to N₂O exposure and the fastest response/recovery times were demonstrated by the sensor element produced by the laser ablation of a composite target prepared by 10 wt% TiO₂ in SnO₂. Additionally, we found that a small amount (below 0.1 wt%) of noble metal (Pt) added to the sensor element substantially improved the gas sensor performance without inducing significant structural and/or morphological changes. Further, we explored how simultaneous irradiation of the sensor surface with UV and visible light changes the sensor properties. The best sensor performance toward N₂O exposure was achieved by irradiating the Pt-doped SnO₂-TiO₂ sensor surface simultaneously with UV and red lights. Full article

In this study, a novel layered WO₃@Co₃O₄ composite electrode was synthesized via a controlled electrodeposition method employing different surfactants to finely tune its nanostructure. The incorporation of polyacrylic acid (PAA) surfactant yielded an optimized P-W@Co electrode with a hierarchical porous morphology and reduced crystallite size, markedly enhancing electroactive site exposure and electron transport. Structural analyses confirmed the amorphous nature of WO₃ and crystalline spinel Co₃O₄ phases forming an integrated composite architecture. Electrochemical characterizations in a three-electrode system revealed that the P-W@Co electrode exhibited superior pseudocapacitive behavior, with an areal capacitance of 11.70 F/cm² at 20 mA/cm² and excellent rate capability, retaining 80% capacitance at 40 mA/cm². Kinetic studies demonstrated enhanced diffusion-controlled charge storage attributed to improved ion accessibility and charge transfer kinetics. To evaluate practical feasibility, asymmetric supercapacitor devices incorporating P-W@Co as the positive electrode coupled with activated carbon as the negative electrode were fabricated. This device showcased a widened operational voltage (1.5 V), outstanding areal capacitance (211 mF/cm²), and energy density (0.066 mWh/cm²). Importantly, the device exhibited exceptional cycling stability, retaining 81.8% capacitance after 7000 cycles. This work signifies a major advancement in surfactant-mediated design of WO₃@Co₃O₄ layered electrodes for scalable, high-performance supercapacitor applications, combining structural stability, enhanced conductivity, and multifaceted charge storage mechanisms. Full article

Urea electrolysis has emerged as a promising alternative to conventional water electrolysis for hydrogen production, owing to low electrical energy consumption as well as organic wastewater. However, the practical implementation of this approach is primarily constrained by the lack of cost-effective and efficient electrocatalysts. Thus, the development of earth-abundant, non-precious metal-based bifunctional electrocatalysts toward both the hydrogen evolution reaction (HER) and the urea oxidation reaction (UOR) is of critical importance. In this context, nanostructured, reduced nickel-cobalt tungstate supported on Ni foam is fabricated as a binder-free, freestanding electrode via a two-step hydrothermal process followed by partial thermal reduction. By systematically tuning the precursor concentrations of Ni, Co, and W, the morphology and electronic structure of the material are effectively modulated. The introduction of oxygen vacancies through partial thermal reduction plays a key role in enhancing charge transport properties. The optimized NiCo@W_0.5/NF electrode exhibits a porous, flower-like architecture and demonstrates excellent bifunctional electrocatalytic activity toward both UOR and HER, accompanied by improved mass transport behavior. When employed as both the anode and cathode for overall urea electrolysis, NiCo@W_0.5/NF requires a low cell voltage of only 1.68 V to achieve a current density of 100 mA cm⁻² and delivers impressive operational stability in an optimized electrolyte composed of 3 M KOH and 0.33 M urea. These results indicate that NiCo@W_0.5/NF is a highly promising and efficient bifunctional electrode material for urea assisted hydrogen production. Full article

The development of interface-engineered, multifunctional nanostructured materials with controllable surface and magnetic properties remains a critical challenge in wastewater treatment and environmental remediation. In this work, a novel GO–CoFe₂O₄–Silicone Magnetic Sponge was successfully fabricated through the integration of graphene oxide and CoFe₂O₄ magnetic nanoparticles within a silicone-modified porous sponge matrix. The resulting material combines superhydrophobicity, oleophilicity, high adsorption capacity, and magnetic responsiveness in a single architecture. The prepared sponge exhibited a high water contact angle of 161.5°, confirming its superhydrophobic nature, while maintaining excellent structural integrity during repeated use. Vibrating sample magnetometry revealed clear ferrimagnetic behavior, enabling rapid magnetic manipulation and efficient recovery of the sponge from aqueous media. The GO–CoFe₂O₄–Silicone Magnetic Sponge demonstrated strong adsorption performance toward a wide range of oils and organic solvents, including chloroform, olive oil, toluene, ethanol, acetone, gasoline, and hexane, with adsorption capacities remaining stable over multiple cycles. Furthermore, the sponge showed outstanding separation efficiency exceeding 98.3% for various oil/water and organic solvent/water mixtures, both in batch and continuous vacuum-assisted separation systems. The adsorption capacity and separation efficiency were retained after repeated adsorption–desorption cycles, indicating excellent reusability and durability. Owing to its synergistic combination of surface chemistry, porous structure, and magnetic functionality, the GO–CoFe₂O₄–Silicone Magnetic Sponge represents a promising candidate for practical applications in oil spill cleanup and wastewater treatment. Full article

Surface-enhanced Raman scattering (SERS) technology, with its high sensitivity and fingerprinting capability, has shown broad application prospects in environmental monitoring, food safety, biomedicine, and other fields. Electrospinning technology can produce flexible nanofiber membranes with high specific surface area and three-dimensional porous structures, providing an ideal platform for constructing high-performance SERS substrates for multiphasic analysis. This review systematically summarizes the fabrication strategies of fiber-based SERS substrates by using electrospinning technology, classified from three perspectives: material composition (polymer-based, ceramic-based, carbon fiber-based, and metal-based), spatial configuration (inner, surface, and inner-surface), and temporal sequence of plasmonic nanostructure (pre-synthesis, pre-reduction, post-reduction, post-modification, etc.). Furthermore, the sampling methods and measurement approaches of such substrates in liquid-phase, solid-phase, and gas-phase detection are discussed, with a focus on their applications in environmental pollution monitoring, food safety inspection, microbial identification, and biomedical diagnostics. Finally, the comparison of different preparation strategies and potential future directions are discussed, which could offer helpful guidance for the design and application of high-performance flexible SERS substrates. Full article