Search Results (4,378)

Ion-imprinted polymers (IIPs) are advanced adsorbents featuring selective recognition cavities for targeted metal ion capture, offering a promising route to high-efficiency separation in extractive metallurgy. In the present work, the evolution, design principles, synthesis strategies, separation mechanisms, and practical applicability of IIPs for metal recovery from complex aqueous matrices are overviewed. Key material components, including functional monomers, crosslinkers, template ions, initiators, solvents, and support materials, are discussed in relation to adsorption capacity, selectivity, kinetics, stability, and recyclability. Major preparation routes, such as surface imprinting, bulk polymerization, in situ polymerization, and sol–gel methods, are critically compared to clarify their advantages and limitations. Recent applications for base metals, precious metals, and rare-earth elements demonstrate that IIPs can achieve high specificity and rapid equilibrium under optimized conditions. However, their translation from simulated solutions to real leachates remains constrained by interfering ions, organic contaminants, mass transfer resistance, incomplete template removal, and matrix complexity. Mitigation strategies, including sample pretreatment, improved polymer architecture, and hybrid supports, are therefore emphasized. Additionally, chemometric modelling, machine learning, or artificial intelligence-assisted design may be implemented to advance the prospects of IIPs in industry. Conclusively, IIPs represent a strong separation platform, yet industrial deployment requires robust validation with real feed streams and scalable regeneration protocols during column operation, as well as under chemically aggressive conditions at scale. Full article

To address the dependence on organic solvents, costly silicon precursors, and complex processing in conventional silica aerogel preparation, this study developed a green and low-cost aqueous route using water glass as the silicon source. The sol–gel process was optimized through an orthogonal experimental design by regulating precursor concentration, pH, temperature, and catalyst dosage, enabling the formation of a stable three-dimensional silica network. Under the optimized conditions, the unmodified silica aerogel exhibited low density, high porosity, and a typical mesoporous structure, with a specific surface area of 707.87 m²/g, an average pore size of 5.75 nm, and a thermal conductivity of 0.0408 W/(m·K). After HMDS vapor-phase modification, hydrophobic methyl groups were introduced onto the aerogel surface, increasing the water contact angle to 132.3°. Among the modified samples, S3 showed the lowest thermal conductivity of 0.0360 W/(m·K), indicating good thermal insulation performance. This work provides a feasible strategy for preparing hydrophobic silica aerogels through a cost-effective aqueous process, showing potential for greener and large-scale production of silica aerogel materials. Full article

This study proposes a process combining alkali-activated potassium feldspar, acid leaching, and sol–gel coupling with supercritical drying to prepare high-performance silica–alumina composite aerogel. The optimal parameters for potassium feldspar alkali-melt activation are a calcination temperature of 350 °C, mass ratio of potassium feldspar to sodium hydroxide of 1:1.2, and calcination time of 120 min, achieving an acid-leaching efficiency of 97.3% for the activated potassium feldspar. The acid leachate, using propylene oxide as a gelling promoter, was processed through aging, solvent exchange, and supercritical drying to yield SiO₂-Al₂O₃ aerogel with typical three-dimensional nanoporous network structure. EDS spectroscopy revealed that the spatial distributions of aluminum and silicon elements were highly coincident and uniformly dispersed. XPS and FTIR further confirmed the formation of Si-O-Al bonds, indicating that aluminum atoms were successfully incorporated into the silico-aluminate tetrahedral network, constructing silicon–aluminum composite framework. The SiO₂-Al₂O₃ aerogel exhibits specific surface area of 660.841 m²/g and a pore volume of 1.321 cm³/g. Its mass loss within the 0–1000 °C range is only 9.55%, far lower than the 28% mass loss of pure aluminum oxide aerogel, indicating that the silicon–aluminum composite structure effectively suppresses high-temperature phase transitions and framework collapse. Full article

Lithium-ion batteries (LIBs) are essential for current technological infrastructure, driving the development of portable electronics, electric vehicles or grid-scale energy storage. The performance and sustainability of LIBs are critically dependent on their anode materials. This comprehensive review analyzes the evolution and characteristics of key anode materials, highlighting the specific properties they confer to the final battery products. Beyond material properties, the synthesis methods employed for these materials, from conventional techniques (such as solid-state reactions, sol–gel, hydrothermal/solvothermal, co-precipitation, etc.) to innovative and greener approaches (like electrospinning and a novel induction furnace-oxidation hybrid method for complex oxides), are a crucial part in the development of sustainable materials. While these methods offer different advantages, the challenges in achieving optimal electrochemical performance, including issues related to material stability, capacity retention and scalability, remain significant for both research and manufacturing industries. Furthermore, a significant focus is placed on strategies for mitigating the environmental impact associated with anode material production, emphasizing the importance of unconventional and sustainable synthesis routes. Ultimately, the sustainable evolution of LIB technology to achieve future energy demands hinges on overcoming existing limitations. This necessitates integrated research combining advanced material modeling and design, scalable and environmentally conscious synthesis techniques and in-depth electrochemical characterization. Full article

Silica aerogel films are highly promising matrices for advanced optical applications, yet balancing ultra-high transmittance with structural stability during functionalization remains a critical challenge. Directly incorporating organic dyes often leads to aggregation and severe photodegradation, necessitating a robust host–guest encapsulation strategy. Herein, we report the fabrication of ultra-transparent, fluorescent silica aerogel films via precisely tailored acid/base two-step sol–gel kinetics and dip-coating. The optimized pure silica matrix achieves a peak visible transmittance of 97.4% and sub-nanometer surface smoothness (RMS = 276.7 pm). By utilizing this pristine network, Rhodamine 6G (Rh6G) and Rhodamine B (RhB) dyes were effectively confined within the amorphous mesoporous pores. Notably, RhB exhibited superior matrix integration, indicated by an H4 hysteresis loop transition and a significantly reduced pore volume (0.019 cm³/g). This mesoporous confinement successfully suppressed dye quenching, prolonging the fluorescence lifetimes to 5.22 ns and 5.36 ns for Rh6G and RhB, respectively. Crucially, we elucidate that the electrostatic and hydrogen-bonding interactions between the silica pore walls and the dye’s xanthene rings elevate the excited-state energy, inducing a distinct matrix-driven emission blue shift. This work provides a scalable pathway for high-performance optical coatings and offers deep insights into host–guest interfacial coupling in gel networks. Full article

The oral cavity represents one of the most demanding operating environments for biomedical coatings, subjecting materials to constant masticatory shear and tribological stress, dynamic temperature fluctuations, salivary enzymatic activity, and continuous fluid turnover that collectively challenge coating adhesion, durability, and longevity. Thermosensitive hydrogels that undergo reversible sol–gel transitions near body temperature offer a uniquely versatile platform for in situ coating formation on complex oral surfaces, enabling minimally invasive application and conformal coverage of irregular anatomical structures—from periodontal pockets and root canal systems to extraction sockets and bone defects. This review examines the application of thermo-sensitive hydrogel coatings across six major oral disease categories: periodontitis, peri-implantitis, bone defects, endodontic diseases, extraction wounds, and oral cancer. We further discuss practical hurdles facing clinical translation, noting that sterilization often degrades these materials, mechanical properties may prove inadequate under masticatory loads, and long-term biosafety data remains limited. This review critically evaluates how these smart coatings can bridge the gap between laboratory innovation and clinical application, offering insights to guide the development of next-generation precision therapies for oral diseases. Full article

The development of efficient visible-light-driven semiconductor photocatalysts is essential for scalable and sustainable green hydrogen production. Among ternary metal oxides, MV₂O₆ (M = Zn, Ni, Cu, Mn, Co, etc.) metavanadates have attracted considerable interest because of their narrow band gaps (~1.8–2.5 eV), strong visible-light absorption, and unique edge-sharing VO₆ octahedral framework that promotes charge separation. This review summarizes recent advances in the design, synthesis, and electronic engineering of MV₂O₆-based photocatalysts for solar water splitting. Since direct particulate overall water splitting has only been demonstrated for MnV₂O₆, whereas ZnV₂O₆, NiV₂O₆, and CuV₂O₆ have mainly been investigated as photoelectrodes, both particulate photocatalytic and photoelectrochemical (PEC) systems are critically examined. The review clearly distinguishes these two configurations, highlighting how PEC studies provide valuable insights into charge transport, interfacial processes, and reaction kinetics while recognizing the additional challenges associated with suspension-based photocatalysis. Fundamental crystal structures, electronic band alignments, and charge-transfer characteristics of MV₂O₆ compounds are discussed, followed by recent advances in synthesis strategies, including hydrothermal, sol–gel, and deep eutectic solvent (DES)-assisted methods, together with morphology and defect engineering. Particular attention is given to oxygen-vacancy formation and its influence on visible-light absorption and charge separation. Modification strategies, including elemental doping, cocatalyst loading, and the construction of Z-scheme and step-scheme (S-scheme) heterojunctions, are critically evaluated for improving photocatalytic efficiency. Finally, the review discusses the key challenges that limit practical applications, including unfavorable band-edge positions, rapid carrier recombination, sluggish surface reaction kinetics, photostability, and the need to establish composition–structure–activity relationships. Future perspectives emphasize rational materials design through advanced characterization, theoretical calculations, and scalable synthesis approaches to accelerate the development of efficient MV₂O₆ photocatalysts for solar-driven hydrogen production. Full article

Hollow glass microspheres, as demonstrated in recent studies, have shown significant importance in the field of composite materials and have emerged as transformative materials in biomedical applications. This is necessitated by their ability to provide a physicochemical gradient, a desirable tool for complex tissues and biological interfaces, through the spatiotemporal release of bioactive factors and nanophase ceramics. HGMs are structures with diameters ranging from 1 to 1000 µm that can be used as support for cell growth, either in the form of a scaffold or a drug delivery system. In this review, we describe the various methods for HGM fabrications, synthesis (e.g., flame spraying, sol-gel processes, spray drying, etc.), structural characterizations, and chemical and physical properties (e.g., densities ranging from 0.1 to 0.6 g/cm³ and compressive strength ranging from 10 MPa to 30 MPa for low and high densities, respectively), highlighting how these methods influence their drug delivery, tissue engineering, bone implants, and nanocarrier abilities. Furthermore, a comprehensive list of other materials and their various biomedical uses is reported. Some of the limitations of existing techniques and future investigations into how HGM can perform as a biomedical material are discussed. Full article

Excessive water production remains one of the most intractable challenges threatening the economic and sustainable development of oil production worldwide. In situ crosslinking polymer gel systems have been widely adopted as cost-effective chemical solutions for water shutoff and conformance control in oilfields. However, the excessively fast gelation kinetics of conventional gel systems at elevated temperatures severely hinders their application in deep, high-temperature reservoirs. To address this gap, this work systematically evaluates a novel Cobalt(II) (Co(II))-crosslinked polymer gel system developed for water control in high-temperature reservoirs. The effects of polymer type, Co(II) concentration, salinity, temperature, and pH on the gelation time, sol–gel transition behavior, and long-term thermal stability of the system were comprehensively investigated. Compared with the most widely used Cr(III)-crosslinked polymer gel systems, the Co(II)-based gel system exhibits a significantly prolonged gelation time at 130 °C, and the gelation time is positively correlated with the molar content of 2-acrylamido-2-methyl propane sulfonate (AMPS) in the polymer backbone. For instance, the gelation time at 130 °C can be remarkably delayed to 16 days when using the AMPS-rich polymer SAV-10. A unique and distinguishing feature of this polymer/Co(II) gel system is its fully reversible thermoresponsive sol–gel transition behavior. Unlike Cr(III)- and Zr(IV)-crosslinked gels, which form permanent and irreversible gels once crosslinked, the Co(II)-based gel system can crosslink into a robust bulk gel at high temperatures and reversibly switch back to a low-viscosity polymer solution when the temperature drops. For example, the SAV-28/Co(II) mixture forms a stable gel at 130 °C and fully reverts to a flowing polymer solution when the temperature is reduced to 80–85 °C. Furthermore, the SAV-10/Co(II) gel exhibits exceptional long-term thermal stability at 130 °C in both 5% NaCl brine and reservoir formation water, with no observable gel volume loss or syneresis after 100 days of high-temperature aging. The combination of tunable delayed gelation, unique thermoreversible sol–gel transition, and excellent high-temperature stability makes this Co(II)-based gel system a promising candidate for water control in oil and geothermal reservoirs, particularly for targeted plugging in the far-wellbore region and other advanced applications requiring dynamic and reversible fluid diversion. Full article

Metal oxide nanoparticles have been the subject of intense research interest because of their remarkable physicochemical properties, such as their high surface area, particle size tunability, outstanding chemical stability, optical activity, catalytic efficiency, and antimicrobial behavior. These properties make them very useful in environmental, biomedical, energy, sensing, agricultural and industrial applications. The chosen synthesis method is important in controlling the morphology, crystallinity, surface charge, band gap and overall performance of metal oxide nanoparticles. They have been prepared using various physical, chemical and biological means, such as sol–gel, co-precipitation, hydro/solvothermal, microwave-assisted, sonochemical, combustion and green synthesis. Of these, green synthesis is gaining more interest as it employs plant extracts, microorganisms, and other biological materials as reducing agents, stabilizing and capping agents that make the process more eco-friendly and cost-effective. Recent advancements in the synthesis and application of metal oxide nanoparticles are discussed. There is an emphasis on the major synthesis routes, the main factors that influence the formation of nanoparticles, the characterization techniques used, and the structure–property relationships uncovered. A special focus is given to the influence of synthesis parameters, such as the type of precursor and the pH, temperature, reaction time, solvents and capping agents, on the properties of nanoparticles. In addition, the uses of metal oxide nanoparticles in photocatalysis, wastewater treatment, antimicrobial activity, drug delivery, biosensing, energy storage, gas sensing, and agriculture are also included. Finally, present challenges, toxicity issues, the problems of large-scale production, and future research directions are discussed to support the practical and sustainable uses of metal oxide nanoparticles. Full article

The sluggish kinetics of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) at air cathodes severely restrict the practical application of rechargeable zinc–air batteries (ZABs). Herein, equimolar lanthanide-doped spinel Co₃O₄ bifunctional electrocatalysts were synthesized via a citric acid-assisted sol–gel method. Among Ce-, Pr-, La-, and Sm-doped catalysts, Sm-Co₃O₄ exhibits the optimal electrocatalytic performance with a high ORR half-wave potential of 0.72 V and superior OER activity with an overpotential of 1.65 V at 10 mA cm⁻², achieving a minimal potential gap ΔE of 0.93 V. Rotating ring-disk electrode (RRDE) measurements and Koutecky–Levich (K–L) analyses confirm the exclusive 4e⁻ ORR pathway. Characterizations reveal that Sm doping modulates the electronic structure and lattice distortion of Co₃O₄, raises the Co²⁺/Co³⁺ ratio (0.59) and creates abundant oxygen vacancies, thereby significantly lowering the overpotentials for both ORR and OER. This study provides new insights for designing high-performance spinel-based bifunctional electrocatalysts for ZABs. Full article

The effect of drying, thermal decomposition, and sintering conditions during the sol–gel synthesis of BaTi₅O₁₁ nanocrystals was investigated to optimize levofloxacin (LEV) photodegradation. Sintering emerges as the dominant factor, and BaTi₅O₁₁ nanocrystals synthesized at 700 °C for 120 min exhibit the smallest grain size, highest specific surface area and abundant active sites, achieving 93.2% LEV degradation within 30 min under UV irradiation. In contrast, excessive sintering temperatures or time induce grain coarsening and size homogenization, which reduce surface area and active sites, thereby impairing photocatalytic performance. The optimized nanocrystals also efficiently degrade other antibiotic pollutants, including ciprofloxacin, norfloxacin, and tetracycline. Radical trapping experiments confirm that •OH is the primary reactive species. Photoluminescence and photoelectrochemical analyses reveal a competition between grain size variation and charge carrier dynamics; however, photocatalytic degradation underscores the dominant role of surface-active sites and specific surface area. Kelvin probe force microscopy (KPFM) further corroborates efficient charge separation, showing a cross-line contact potential difference (ΔV_CPD) of approximately 90 mV, indicative of facile hole migration to the crystal surface. Collectively, these findings elucidate the processing–microstructure–property relationships in BaTi₅O₁₁ nanocrystals and provide a robust basis for the rational design of high-performance photocatalytic systems for antibiotic pollutant remediation. Full article

Magnesium alloys are used or considered for lightweight structures and biodegradable implants, but high electrochemical activity, limited wear resistance, and localized corrosion still limit their service reliability. Plasma electrolytic oxidation (PEO), also called micro-arc oxidation (MAO), forms an adherent ceramic scaffold. Discharge channels, interconnected pores, thermal cracks, and a mechanically weak outer layer mean that the as-formed coating is rarely a complete protective system. This review examines advanced PEO/MAO-based composite coatings through a process–structure–function lens and develops an application-oriented design framework. The discussion covers PEO/MAO process-window control, electrolyte and particle engineering, sol–gel and polymer sealing, layered double hydroxide/inhibitor systems, self-healing reservoirs, superhydrophobic and slippery interfaces, Ca-P/hydroxyapatite and polymer biofunctionalization, and duplex coatings for wear, electrical, and thermal functions. Emphasis is placed on how these modules regulate defect connectivity, mass transport, interfacial stability, damage response, tribocorrosion, and biodegradation, as well as on the evidence needed to support each claimed function. The analysis indicates that coating performance is governed not by multilayer complexity alone, but by the compatibility among the ceramic scaffold, functional module, dominant failure mode, and service-specific validation protocol. Chloride-exposed structures require durable pore sealing and active inhibition; wear-critical components require coupled corrosion–wear assessment; and biodegradable implants require a degradation window that balances corrosion moderation, cytocompatibility, biofunctionality, and residual mechanical integrity. Remaining challenges include interfacial durability, finite inhibitor reservoirs, wetting-state instability, process reproducibility, scale-up, and life-cycle impacts. The proposed process maps and validation criteria are intended to support modular, testable, and application-specific PEO/MAO surface systems for magnesium alloys. Full article

Confining a phase-change material (PCM) within a polymer shell yields leak-proof, mechanically robust latent-heat storage media, but selecting a shell chemistry and polymerization route requires balancing competing targets: latent-heat storage density (ΔH, the melting enthalpy per unit capsule mass), core loading content (LC), capsule diameter (d), and a melting temperature (T_m) matched to the application. Because the literature characterizes each method–shell–core combination in isolation, these structure–property relationships cannot be compared quantitatively across studies. We present a proof-of-concept, data-driven framework linking shell and process descriptors to encapsulation performance. From a curated dataset of 90 micro- and nano-encapsulated PCM records (53 with measured ΔH) spanning 11 encapsulation routes and eight shell material families, Random Forest (RF) and Gaussian Process (GP) surrogates predict ΔH, and a non-dominated sorting genetic algorithm (NSGA-II) optimizes ΔH, LC, and d over the continuous (T_m, LC) space for every method–shell–core trio with at least three records (n = 11). Benchmarked against mean, linear-LC, and physics-informed baselines under repeated cross-validation, the surrogates match but do not exceed the elementary baselines (median R² ≈ 0.33), a result we report honestly given the modest sample size. The Matérn GP provides borderline-calibrated uncertainty, supporting a robust, extrapolation-penalizing NSGA-II. Hypervolume rankings place emulsion polymerization, sol–gel silica, and in situ polymerization as the top-performing methods under both nominal and robust criteria. Presented as a methodology demonstration rather than a definitive ranking, the framework, with full code and data, is a reusable approach for structure–property quantification of polymer-encapsulated PCMs as experimental data accumulate. Full article

Functional coatings have evolved from their early role as passive barriers against corrosion and wear into engineered interfaces that actively mediate the interaction between a bulk material and its environment. This review traces the evolution of coating technologies from traditional macroscopic protective layers to nanoscale and multifunctional systems, and finally to smart and stimuli-responsive architectures. Advanced deposition and surface modification techniques are examined, including atomic layer deposition, physical vapor deposition, electrochemical and sol–gel approaches. The discussion is structured around two complementary application domains: extreme energy environments, focusing on coatings developed for advanced nuclear systems, and modern medical implants, including bioactive and antimicrobial surfaces and drug-delivery interfaces. The review highlights that, despite the differences between reactor and biomedical environments, both sectors share a common set of design principles and challenges, including interfacial adhesion, mechanical durability, the dual role of nanostructuring, and the trade-off between architectural complexity and operational reliability. Long-term stability, scalability, and standardized validation remain key barriers to deployment, while data-driven design and the deliberate integration of multiple functions emerge as the principal directions for future development. Full article