Materials最新文献

The growing demand for sustainable and distributed energy solutions has driven increasing interest in triboelectric nanogenerators (TENGs) as platforms for energy harvesting and self-powered sensing. Biowaste-based triboelectric nanogenerators (BW-TENGs) represent an attractive strategy by coupling renewable energy generation with waste valorization under the principles of the circular bioeconomy. This review provides a comprehensive overview of BW-TENGs, encompassing fundamental triboelectric mechanisms, material categories, processing and surface-engineering strategies, device architectures, and performance evaluation metrics. A broad spectrum of biowaste resources-including agricultural residues, food and marine waste, medical plastics, pharmaceutical waste, and plant biomass-is critically assessed in terms of physicochemical properties, triboelectric behavior, biodegradability, biocompatibility, and scalability. Recent advances demonstrate that BW-TENGs can achieve electrical outputs comparable to conventional synthetic polymer TENGs while offering additional advantages such as environmental sustainability, mechanical compliance, and multifunctionality. Key application areas, including environmental monitoring, smart agriculture, wearable and implantable bioelectronics, IoT networks, and waste management systems, are highlighted. The review also discusses major challenges limiting large-scale deployment, such as material heterogeneity, environmental stability, durability, and lack of standardization, and outlines emerging solutions involving material engineering, hybrid energy-harvesting architectures, artificial intelligence-assisted optimization, and life cycle assessment frameworks.

Amine-functionalized solid adsorbents are widely recognized as promising candidates for direct air capture of CO₂; however, their practical deployment remains constrained by humidity-dependent adsorption behavior and poor packed-bed operability arising from irregular particle morphology and fines generation. Rather than focusing solely on maximizing intrinsic adsorption capacity, this study addresses these process-level limitations through an integrated design strategy combining particle morphology control with surface chemistry optimization. Uniform spherical magnesium silicate particles with a mean diameter of approximately 15 μm were synthesized via a water-in-oil emulsion route to suppress fines formation and reduce hydrodynamic resistance. Controlled acid pretreatment was subsequently applied to adjust surface hydroxyl accessibility and enable efficient amine grafting without altering bulk composition. The optimized spherical magnesium silicate amine adsorbents exhibited pronounced humidity-enhanced carbon dioxide capture, achieving capacities of 1.7 to 1.8 millimoles/g at 50% relative humidity, representing an approximately fourfold increase compared with dry conditions. This enhancement is attributed to a humidity-induced mechanistic transition from carbamate formation under dry conditions to water-assisted bicarbonate formation under humid conditions. Complete regeneration was achieved at 100 °C, with stable adsorption desorption behavior maintained over ten consecutive cycles, demonstrating short-term reversibility. These findings highlight morphology controlled scalability. Future work should prioritize durability beyond 100 cycles, mechanical robustness, and techno-economic viability at scale.

The increasing demand and production of neodymium-iron-boron-based permanent magnets (NdFeB-PMs) for the electronics, energy sector, and automobile industries led to disposal consequences. The NdFeB-PMs contain a substantial amount of rare earth elements (REEs). Although China is the largest exporter of REEs to the world, it has applied some restrictive policies in terms of supply chain and taxes. To address such issues, this review systematically examines current recycling techniques, including short-loop, hydrometallurgy, pyrometallurgy, and hybrid processes, and the integration of Machine Learning (ML) to the leaching process, with a particular focus on their impact on industrial capability, economic viability, and environmental concerns. However, a comparative study highlights ongoing challenges to large-scale implementation, including fragmented waste sources, gaps between efficient processes and environmental sustainability, and a lack of regulatory and infrastructure support. To address these challenges, technical innovation in automated disassembly systems and selective REE recovery via ML was discussed, along with legislative initiatives such as Extended Producer Responsibility (EPR) and waste monitoring procedures. Furthermore, ecologically and economically feasible solutions were optimized through ML-based recycling procedures to increase the leaching efficiency and the recovery of the REEs. This analysis emphasizes the importance of collective technological, environmental, and policy initiatives to achieve sustainable NdFeB recycling and long-term resource availability. These findings offer important perspectives into developing effective and environmentally friendly NdFeB waste recycling solutions via the integration of ML.

Highly active interfaces are crucial to the hydrogen adsorption performance of nanomaterials. However, it remains challenging to conveniently and efficiently regulate atomic stacking characteristics. Here, we present a straightforward yet effective strategy for generating a high density of stepped atoms at the surface of thin films by controlling the migration behavior of sputtered atoms during deposition. Tuning sputtering power and substrate temperature yields wide-scale stepped interface structures, thus generating irregular conical columnar nanocrystals. Benefiting from the active and stable stepped atoms at the zigzag interface, the samples exhibit an excellent threshold pressure at 200 °C and a hydrogen adsorption of 110.06 cm³/g at 6 MPa, which is 2.2 times higher than that of conventional Pd thin films. Based on the control of nucleation and crystal growth during magnetron sputtering deposition, this method provides appropriate energy for surface atomic migration on columnar crystals, achieving high-density stepped interface structures. It can be readily extended to other substrates and noble metal systems, thus offering a novel strategy and guidance for the design of efficient and cost-effective hydrogen-interactive materials.

(1) Objective: To compare the marginal and internal fit of 3D-printed and milled three-unit fixed dental prostheses (FDPs) made from tetragonal zirconia polycrystal (3Y-TZP). (2) Methods: Three-unit FDPs were designed for a typodont maxillary model with crown preparation for the second premolar and second molar. Nominal cement gap widths were set to 30 µm at the margins and 80 µm internally. A total of 40 FDPs (n = 10/group) differing in wall thickness (w = 0.6/1.0 mm) and support structures (with/without a stiffening frame) were fabricated from 3Y-TZP by 3D printing. A total of 10 milled FDPs with w = 0.6 mm served as a control group. After adhesive cementation on the respective replicated maxillary models, FDPs were sectioned and the cement gap dimension was assessed with a digital microscope. The marginal and internal fit found for the different test groups were compared using non-parametric tests. (3) Results: The best marginal fit-qualified by median/maximum marginal gap width-was given for milled FDPs (79/127 µm vertical; 85/171 µm tangential), whereas the marginal fit of 3D-printed FDPs with w = 0.6 mm and regular support structures was the worst (144/284 µm vertical; 107/198 µm tangential). Use of an additional support frame improved the marginal fit of 3D-printed FDPs, in particular FDPs with w = 0.6 mm (108/197 µm vertical; 87/161 µm tangential). (4) Conclusions: 3D-printed zirconia FDPs showed conditionally comparable marginal and internal fit as their milled counterparts, but with slightly higher scattering. When fabricating thinner 3D-printed FDPs, additional support structures are mandatory to achieve clinically well-fitting restorations.

Finely twinned microstructures are widely observed in metals and alloys but the underlying formation mechanisms remain debatable. In particular, the role of internal stresses in promoting these inhomogeneous patterns is still not clear. By incorporating a geometrically nonlinear microelasticity theory into phase-field framework, we study the evolution of elastic fields resulting from the growing deformation twins (DT) at grain boundaries in fcc metals. Simulations in two model systems, i.e., Ni and CoCrFeMnNi (a high-entropy alloy), show that as the external applied stress increases, the internal elastic fields begin to develop undulations with stripelike patterns owing to the significant geometrical nonlinearity associated with DT. This elastic undulation, absent in linear modeling, is initially nonuniform inside the grain and becomes global and coarsened, exhibiting a characteristic wavelength of ~1-2 nm. The predicted elastic inhomogeneity leads to a stack of alternating crystal orientations favored by the undulating local stress fields. The resemblance of our predicted stress undulation and the stripelike patterns in experiments may suggest a universal mechanistic origin of the nanotwinned microstructures widely observed in deformation twinning and displacive transitions.

This study aims to address the issue of asphalt pavement performance deterioration caused by chloride salt erosion. Layered double hydroxides (CLDHs) calcined at different temperatures, including 400 °C, 500 °C, and 600 °C, were used for the modification of asphalt binder. The structural evolution and chloride ion adsorption characteristics of CLDHs were analyzed. The adsorption kinetic behavior of CLDHs for chloride ions was investigated by combining adsorption kinetic experiments and electrochemical titration experiments. Through characterizing the interfacial adhesion performance between CLDH-modified asphalt binder and aggregates, the chemical composition of asphalt-ash binder before and after salt corrosion, and the leaching stability of organic substances in an environment with abundant chloride ions, the influence of CLDHs on the salt corrosion resistance of asphalt-ash binder was quantified. The results indicate that chloride adsorption by CLDHs is predominantly chemisorption-driven. With increasing calcination temperature, the chloride adsorption capacity of CLDHs gradually improved. In chloride-rich environments, CLDHs significantly enhanced the interfacial adhesion between asphalt binder and aggregates, particularly for coarse aggregates with a particle size of 9.5-13.2 mm. Furthermore, CLDHs effectively suppressed the formation of carbonyl and sulfoxide groups during salt corrosion and substantially decreased the leaching of organic components from asphalt binder. In summary, CLDHs can specifically enhance the salt corrosion resistance of asphalt binder, with the 600 °C-CLDHs demonstrating the most significant improvement, followed by the 400 °C-CLDHs, while the 500 °C-CLDHs performed the least effectively.

The global population growth and the demand for agricultural food products have generated a significant volume of agro-industrial by-products which, inadequately managed, affect the quality of the environment. The construction industry, a large consumer of raw materials and energy, constitutes an important source of waste and greenhouse gas emissions. In this context, the circular economy provides the right framework for the valorization of such natural materials, allowing us to obtain innovative sustainable building materials. The paper presents experimental research that led to the development of twelve plasters incorporating rice husks that were characterized by means of thickness (2.71-6.26 mm, when applied on concrete, and 4.20-10.29 mm, when applied on plasterboards), adhesion to the concrete surface (0.18-0.65 N/mm²), thermal conductivity (0.072-0.083 W/m·K), and impact on indoor air quality, in terms of total volatile organic compounds (TVOCs) emissions (3272-9470 µg/m³). The determined levels of the emissions suggest the possibility that by extending the monitoring for at least seven days after application, the information is more relevant. The findings confirmed that using the rice husks for the obtaining of such plasters represents a possible direction of valorization in construction; additional research is necessary for a more precise delineation of the characteristics of these products.

The coexistence of Cu in copper sulfate electrolyte significantly affects the microstructure and performance of the copper foil. So far, there has been little quantitative analysis of Cu⁺ in the electrolyte during the copper foil production process. This paper fabricated a 2,2'-Biquinoline (BIQ) modified expanded graphite (EG) electrode electrochemical sensor for the selective determination of Cu⁺. EG, with its large specific surface area and excellent adsorption and electrochemical properties, significantly enhances analytical sensitivity. Additionally, BIQ's specific coordination with Cu⁺ improves the sensor's rapid and effective quantification of Cu⁺ in the electrolytic copper foil electrolyte. The linear equation of this sensor is I = 0.03769 + 0.29997 × c (R² = 0.9989), with a detection limit of 8 μg/L (S/N = 3). The BIQ-modified EG electrode has good selectivity for Cu⁺, with a recovery rate for cuprous ions of 101.00% to 105.00% under the coexistence of 10,000 times Cu²⁺, and an RSD of less than 2%. This sensor's efficient, sensitive, and selective detection of Cu⁺ can be an effective method to improve the quality of electrolytic copper foil products.

This study aims to address the limitations of dense polyvinylidene fluoride (PVDF) membranes grafted with vinyl ethyl imidazole tetrafluoroborate, which exhibit low hydrophilicity and ionic conductivity in vanadium redox flow batteries (VRFBs). To improve these properties, water-soluble β-cyclodextrin was introduced as a porogen to fabricate asymmetric porous membranes. The porous structure was controlled by varying the porogen content (10-50 wt%), and the resulting membranes were characterized using FTIR, SEM, TGA, and electrochemical tests. This unique architecture led to a significant enhancement in ionic conductivity (to 71.69 mS/cm, from 6.73 mS/cm for the dense membranes), porosity (up to 40.24%), and water uptake (up to 31.8%), while maintaining robust mechanical strength (tensile strength 14.96 MPa) suitable for VRFB assembly and operation. In single-cell performance tests across a range of current densities, clear trends emerged: Coulombic efficiency (CE) decreased with higher porosity, whereas voltage efficiency (VE) followed the opposite trend. Consequently, the optimal energy efficiency (EE) was achieved with the intermediate porogen content, successfully balancing conductivity and selectivity. This work demonstrates a green and scalable approach to developing high-performance porous membranes for VRFB applications.