Superwettability underpins the next generation of membrane technology, enabling ultrafast liquid transport, selective permeation, and exceptional antifouling performance in oil-water separation. Here, the integration of nanocomposites and metal organic frameworks (MOFs) into polysulfone membranes is shown to exert precise control over interfacial wetting behaviour. Contact angle measurements, in accord with classical wetting models, reveal that judicious engineering of surface chemistry and nanostructure yields instantaneous water spreading manifested by contact angles as low as 35.7 ± 1.8° for nanocomposite membranes, and 45±1.3° for MOF-integrated analogues, establishing a regime of strong hydrophilicity. Scanning electron microscopy reveals dramatic morphological evolution upon nanocomposite and MOF incorporation, while FTIR spectroscopy confirms the introduction of hydrophilic functional groups that reduce surface free energy. Atomic force microscopy demonstrates that, counter to the Wenzel hypothesis, strong hydrophilicity emerges even as surface roughness decreases, underscoring the primacy of surface chemical modification over topographical effects. These findings elucidate a mechanistic continuum linking wetting theory, nanoscale engineering, and interfacial fluid dynamics, and delineate a rational design strategy for high-performance, sustainable membrane systems targeting advanced oily wastewater remediation.
This study investigates ZnO thin films incorporating copper nanoparticles (Cu NPs) as efficient photocatalysts for solar-driven wastewater treatment. The ZnO@Cu composite films were fabricated by in-situ integration of Cu NPs into the ZnO during atomic layer deposition (ALD) growth. Structural characterization by X-ray diffraction, X-ray photoelectron spectroscopy, and electron microscopy confirmed the preservation of the wurtzite ZnO structure, with metallic Cu NPs of an average size of around 80 nm embedded into the semiconductor matrix. UV–vis spectroscopy demonstrated enhanced visible-light absorption by the ZnO@Cu films - which is attributed to the localized surface plasmon resonance in Cu nanoparticles, while Kelvin probe force microscopy revealed local variations in ZnO surface potential in the vicinity of Cu NPs, indicating electron transfer from ZnO to Cu and the formation of a Schottky-type barrier at ZnO/Cu interface. Photocatalytic degradation of methylene blue (MB), Rhodamine B (RhB), and caffeine under simulated solar irradiation demonstrated significantly enhanced photocatalytic performance of the ZnO@Cu films compared to pristine ZnO. The ZnO@Cu photocatalyst achieved degradation efficiencies of 78.2%, 89.6%, and 38.5% for MB, RhB, and caffeine, respectively, in contrast to pure ZnO, which showed degradation efficiencies of 44.4% (MB), 42.4% (RhB), and 14.2% (caffeine), confirming the effectiveness of the ZnO@Cu composite toward both dye and emerging organic pollutants. The improved photocatalytic performance is attributed to the injection of hot-electrons from Cu NPs into the ZnO conduction band, as revealed from our photoconductivity measurements, which show nearly two orders of magnitude larger photoinduced carrier generation in ZnO@Cu films under simulated sunlight illumination. These results demonstrate that Cu NPs effectively enhance charge-carrier generation and utilization in ZnO, leading to improved solar-driven photocatalytic activity.
A hierarchical BaTiO3/MgIn2S4 (BTO/MIS) heterostructure was synthesized via a one‑step solvothermal route to couple the strong piezoelectric potential of BaTiO3 with the visible‑light activity of MgIn2S4. X-ray diffraction, electron microscopy, and XPS confirm the intimate interfacial contact between BTO and MIS nanosheets, establishing an n–n S-scheme junction that promotes internal band bending and an intrinsic electric field for vectorial charge migration. Under simultaneous 70 W simulated solar irradiation and low‑power (20 kHz, 20 W) ultrasonication, the optimized 2.0‑BTO/MIS composite decomposed 95 % of the fluoroquinolone antibiotic norfloxacin (10 mg L-1) within 90 min, nearly an order of magnitude faster than either photocatalysis or piezocatalysis alone and corresponding to a synergy factor of 6.9 and 89.6 %. Electrochemical impedance and photoluminescence analyses revealed markedly lower charge-transfer resistance and suppressed electron–hole recombination compared to the parent phases, while transient piezocurrent measurements demonstrated an efficient conversion of mechanical energy into reactive charge carriers. Degradation proceeded most effectively in acidic solution (optimum pH ≈ 3), where the positively charged antibiotic was strongly adsorbed onto the negatively polarised surface. Radical‑quenching experiments identified valence‑band holes and •OH as the dominant oxidants, consistent with the S‑scheme mechanism. Collectively, these results demonstrate that integrating piezoelectric BaTiO3 with visible‑light‑responsive MgIn2S4 in an S‑scheme configuration affords a robust piezo‑photocatalyst capable of harvesting both solar and low‑frequency mechanical energies to drive rapid, mineralization-level removal of persistent pharmaceutical pollutants from water
Mesoporous silica nanoparticles (MSNs) have emerged as versatile drug delivery systems with promising applications in diagnostics and therapy. However, structural heterogeneity among MSNs and limited spatio-temporal tracking capabilities have resulted in inconsistent in vivo data, hindering the establishment of reliable pharmacokinetics, metabolism, and structure–activity relationships (SAR). Here, we report the design, synthesis, and interface engineering of a multilayered MSN (MoMSN) theranostic platform comprising a molybdenum (IV) oxide (MoO₂) core for intrinsic, label-free in vivo tracking via X-ray fluorescence (XRF) imaging, a fluorophore-doped silica layer for tissue-level visualization, and a mesoporous silica shell for potential drug delivery. Following comprehensive physicochemical characterization and in vitro safety assessment, the nanoparticles were intravenously administered to mice for multimodal imaging and biodistribution analysis. Whole-body XRF imaging revealed that MoMSNs exhibited rapid systemic turnover, with transient accumulation in the lungs followed by minimal retention in the liver and spleen. Immunofluorescence analysis confirmed confinement within major blood vessels and decreased macrophage uptake in the liver and spleen. Surface PEGylation further reduced organ retention as well as macrophage uptake. These findings demonstrate that surface chemistry strongly influences the in vivo fate of MSNs and that PEGylation promotes rapid clearance while minimizing uptake by the mononuclear phagocyte system. Importantly, this work establishes MoMSNs as an intrinsically traceable nanoplatform for quantitative whole-body tracking without external radiolabels, enabling more reliable evaluation of nanoparticle biodistribution and structure–activity relationships.
As industries such as aerospace, automotive, and marine adopt new materials and designs, the need arises for advanced processing techniques which can shape this material while achieving required part properties. Aluminum alloys, widely used for their low weight, high strength, and corrosion resistance, still face limitations in hardness, wear resistance, and surface fouling. Surface laser processing offers a method to overcome these limitations. Specifically, femtosecond laser ablation offers a high-precision, low-defect method for surface texturing, capable of producing nano- and microscale features. This study investigates the femtosecond laser ablation threshold and material removal behavior of four aluminum alloys—99% pure Al, AA6061, AA7075, and Scalmalloy®—using a 4 W, 400 fs pulse laser at repetition rates up to 1 MHz. The results show significant variability in feature sizes, with AA6061 exhibiting the largest crater diameters depth for and pure Al displaying the greatest ablation depth (up to 4.1 μm) for the same process parameters. Increasing laser power resulted in a linear increase in ablation depth, while pulse repetition rate exhibited an inverse linear trend with depth, contrary to what would be expected from conventional laser processing. X-ray photoelectron spectroscopy (XPS) revealed that laser processing had minimal impact on surface chemistry, with aluminum oxide remaining the dominant component. Differences in physical properties, such as conductivity, reflectivity, and melting point, were identified as the key factors influencing ablation behaviour. These findings underscore the need for material-specific optimization when developing femtosecond laser-based processing techniques for aluminum alloys.
Understanding the growth mechanism of coating formed by plasma electrolytic oxidation in a dual-phase AZ91 alloy is essential for analyzing the mechanical and corrosion properties of the resulting coating. The growth mechanism of magnesium phosphate coatings on a cast AZ91 alloy was investigated as function of time and formation current density. Surface observation revealed a non-simultaneous oxide growth at 100 A/m2, where oxidation preferentially initiated at the α-matrix and α/β interfaces, and eventually burying the intact β-phase through lateral oxide expansion. The coatings, which composed primarily of amorphous Mg(OH)2, exhibited a maximum hardness of 120 HV. Increasing the current density to 400-800 A/m2 significantly accelerated the growth rate, enabling direct oxidation of the β-phase, leading to the formation of Al-rich oxide compounds embedded within crystalline Mg3(PO4)2. Polarization test showed that the coatings effectively suppressed the negative differential effect and ennobled the pitting potential of the alloy. Superior mechanical hardness and corrosion resistance were achieved at 800 A/m2. The electrochemical impedance spectra analysis indicated that the barrier layer response evolved from a purely capacitive to a diffusion-controlled process after 1 h exposure, accompanied by the gradual development of temporary passivation up to 3 h.
Biodegradable magnesium (Mg) alloys have emerged as promising implant materials; however, their clinical application remains constrained by high corrosion rates. This study addresses this limitation through surface modification of 3D–printed WE43 Mg alloy using a composite coating comprising calcium phosphate (CaP) and phosphoserine (PS) fabricated via a wet chemistry approach at varying molar ratios. Structural and chemical analyses were conducted using X–ray diffraction (XRD) and X–ray photoelectron spectroscopy (XPS) to examine the effect of PS incorporation on dicalcium phosphate dihydrate (DCPD) and octacalcium phosphate (OCP) phases. PS addition to DCPD reduced crystallinity, increased surface roughness, and decreased the contact angle, thereby enhancing wettability. The incorporation of PS into OCP slightly alters the XRD peak intensities, suggesting a modification in crystallinity. XPS analysis confirmed chemical bonding between the coating and substrate, resulting in enhanced interfacial adhesion. The DCPD–PS–WE43 (1:1) and OCP–PS–WE43 (1:2) compositions exhibited the highest adhesion strengths as measured by shear test (5.00 ± 0.41 N and 10.33 ± 0.60 N, respectively). Electrochemical analyses demonstrated that coatings with higher adhesion strength exhibited lower corrosion current densities and reduced corrosion rates. In vitro testing using MC3T3–E1 pre–osteoblasts showed improved cell morphology and proliferation on OCP–PS–WE43 (1:2) compared with uncoated alloy. These findings indicate that the OCP–PS–WE43 (1:2) composite coating enhances both corrosion resistance and biocompatibility, supporting its potential as a surface modification for next–generation biodegradable orthopaedic implants.
Ascorbic acid is an essential antioxidant involved in redox homeostasis, immune response, and metabolic processes. The development of low-cost high accurate electrochemical sensors is critical to overcome conventional glass carbon electrodes (GCE). In this report, we report the first non-enzymatic electrochemical ascorbic acid sensors based on nickel diselenide (NiSe2) grown on flexible carbon sheets using solvothermal process. Furthermore, the cobalt (Co) doping of various concentrations on NiSe2 was synthesized and their electrochemical performances were evaluated. Structural and surface analyses using X-ray diffraction, field emission scanning electron microscope, and X-ray photoelectron spectroscopy confirm the successful formation and uniform distribution of Co on surface of NiSe2 over the carbon sheet matrix. The electrochemical performance of the carbon sheet-based Co-doped NiSe2 sensing electrode was evaluated using cyclic voltammetry and amperometric measurements, revealing efficient and selective redox properties. The sensor exhibits the linear response over the concentration range of 0.01 mM to 1 mM, with a rapid response of 2.6 s, and a low detection limit of 8.19 μM at an applied potential of 0.35 V with excellent selectivity. These results demonstrate the strong potential of Co doped NiSe2 sensing electrode as low-cost, flexible and disposable sensing platforms for electrochemical ascorbic acid sensing.
Superwettability underpins the next generation of membrane technology, enabling ultrafast liquid transport, selective permeation, and exceptional antifouling performance in oil-water separation. Here, the integration of nanocomposites and metal organic frameworks (MOFs) into polysulfone membranes is shown to exert precise control over interfacial wetting behaviour. Contact angle measurements, in accord with classical wetting models, reveal that judicious engineering of surface chemistry and nanostructure yields instantaneous water spreading manifested by contact angles as low as 35.7 ± 1.8° for nanocomposite membranes, and 45±1.3° for MOF-integrated analogues, establishing a regime of strong hydrophilicity. Scanning electron microscopy reveals dramatic morphological evolution upon nanocomposite and MOF incorporation, while FTIR spectroscopy confirms the introduction of hydrophilic functional groups that reduce surface free energy. Atomic force microscopy demonstrates that, counter to the Wenzel hypothesis, strong hydrophilicity emerges even as surface roughness decreases, underscoring the primacy of surface chemical modification over topographical effects. These findings elucidate a mechanistic continuum linking wetting theory, nanoscale engineering, and interfacial fluid dynamics, and delineate a rational design strategy for high-performance, sustainable membrane systems targeting advanced oily wastewater remediation.
Copper is widely used in electronic applications, however, its rapid oxidation under ambient and corrosive environments significantly limits long-term performance. Here, we report highly stable polyaniline–copper (PANI–Cu) hybrid composites achieved by controlling the redox state of the PANI matrix. Three composites (PANI EB–Cu, PANI EB/LB–Cu, and PANI LB–Cu) were synthesized via a chemical reduction process. Increasing the reduction degree of PANI enhances the density of electron-donating amine groups, promoting strong coordination with copper and improving particle dispersion. As a result, PANI LB–Cu exhibits a higher work function (4.94 eV) and superior resistance to oxidation. After thermal sintering, it exhibits an electrical conductivity of 1.2 × 104 S cm-1, which remains stable over 4728 h under ambient conditions. In a seawater immersion test, PANI LB–Cu maintains its conductivity even after 560 h with minimal degradation, whereas conventional copper rapidly deteriorates. X-ray photoelectron spectroscopy reveals that the PANI matrix undergoes preferential oxidation, acting as a sacrificial layer that protects the copper from corrosion. These findings demonstrate that redox-state engineering of conducting polymers is an effective strategy for developing highly stable metal–polymer hybrid conductors for use in harsh environments.
Continued scaling of dynamic random-access memory (DRAM) capacitors demands simultaneous achievement of high capacitance density and extremely low leakage current at ever-decreasing physical thickness, making interfacial chemistry and defect control as critical as the choice of high-k dielectric. Here, we propose a HfN sacrificial interlayer to mitigate interfacial redox reactions when integrating Mo electrodes with an ALD-grown HfO2/ZrO2/HfO2 (HZH) nanolaminate designed to exploit the morphotropic phase boundary (MPB)-related high permittivity. A 1 nm-thick sputtered HfN layer is selectively oxidized during subsequent atomic layer deposition, forming an HfOxNy interlayer that suppresses formation of defective MoOx and reduces Mo species penetration into the dielectric, as confirmed by cross-sectional transmission electron microscope study as well as chemical analyses. Pulse-based charge/discharge measurements yield k ≈ 59 at operating-relevant fields for 6.0–6.5 nm physical thickness, while the leakage current density is reduced by ≈ 2–3 orders of magnitude compared with the HfO2-interfaced control, satisfying <10–7 A cm-2 at 0.8 V (VDD/2) for optimized stacks. The best device achieves an equivalent oxide thickness down to 0.39 nm within the DRAM operating window and maintains both dielectric response and leakage stability up to 109 endurance cycles. This interfacial “oxygen-buffering” strategy provides a practical process window for Mo-electrode, MPB-engineered fluorite-structured nanolaminate capacitors targeting advanced DRAM nodes.
The persistence of pharmaceutical antibiotics in aquatic environments remains a critical challenge due to their poor removal by conventional treatment processes. Herein, hierarchical TiO2/ZnO inverse opal (IO) photonic crystal heterostructures are fabricated via a double-templating method combined with atomic layer deposition (ALD), enabling precise control of surface architecture and heterointerfaces. The resulting materials exhibit highly ordered frameworks with pore structures and crystalline anatase TiO2 and wurtzite ZnO phases, as confirmed by SEM, XRD, and Raman spectroscopy. UV–Vis spectroscopy showed two photonic band gap (PBG) regions at ∼400 nm and ∼590 nm, indicating enhanced light–matter interaction with strong slow-light effects for surface light harvesting, while the TiO₂/ZnO IO exhibited a red-shifted PBG at ∼590 nm (∼15 nm shift). Photocatalytic activity was assessed using Ciprofloxacin (CIP) and Rhodamine 6 G (Rh6G) under UV and visible-light irradiation. Under UV light, the hierarchical IO heterostructures achieved up to 70 % Rh6G degradation in 240 min and 60–65 % CIP degradation in 120 min, outperforming the single-component IOs. Under visible light, the TiO2/ZnO and ZnO/TiO2 IOs further improved performance, reaching 77–80 % Rh6G degradation and 74–75 % CIP degradation, respectively. This improvement resulted from the dual-templating strategy, which formed a highly ordered hierarchical photonic structure with a stronger slow-photon effect, enhanced light–matter interaction, more available adsorption sites, and more efficient charge separation across the TiO2/ZnO heterojunctions.
A unified thermodynamic framework is developed for the structural and energetic characterization of UiO-66 metal–organic frameworks using inverse gas chromatography at infinite dilution. Pristine UiO-66 and amino-, formic acid-, and acetic acid-functionalized derivatives were investigated over 313.15–383.15 K. The standard Gibbs free energy of adsorption is expressed as a function of temperature and specific surface area, demonstrating the intrinsic dependence of adsorption thermodynamics on adsorbent structure. This leads to the generalized relation, ΔGa0(T,S)=ΔHa0(S)−TΔSa0(S), in which adsorption enthalpy and entropy become continuous structural functions rather than invariant quantities across a porous-material family. The effective molecular surface area of adsorbed solvents also depends on temperature and surface structure, revealing changes in molecular organization within the adsorption layer. Lewis acid–base interactions were analyzed by applying the Hamieh five-parameter thermodynamic model independently to adsorption enthalpy and entropy. Statistical analysis confirms the superiority of nonlinear higher-order models over conventional linear approaches and reveals correlations among acidic, basic, amphoteric, and cooperative interaction parameters. Functionalization markedly modifies Lewis acidity, basicity, and polar surface energy while only weakly affecting London dispersive interactions. A new methodology is further introduced to determine the polar surface energy of adsorbed solvent molecules, demonstrating that the adsorbed phase possesses thermodynamic surface properties governed by solvent–framework interactions. Overall, the proposed framework unifies adsorption thermodynamics, molecular organization, Lewis acid–base interactions, and surface energetics, providing a general methodology for characterizing and rationally designing advanced porous materials.
Spent coffee grounds (SCG) are a significant organic waste with potential for energy recovery in anaerobic digestion. However, their processing is limited by their high lignin content and complex lignocellulosic structure. This work aimed to compare photolytic and photocatalytic pre-treatment of SCG. Changes in lignocellulosic composition, particle morphology, and biogas production were evaluated. Photocatalytic pre-treatment was performed under UV radiation in the presence of a TiO2 photocatalyst. This pre-treatment caused significant reduction in lignin content. SEM analysis confirmed a significant disruption of the biomass structure. These modifications were associated with an approximately 23% increase in biogas production and a 16% increase in methane yield. Furthermore, photocatalytic treatment reduced the caffeine content of the substrate. Photolytic pre-treatment, which took place under UV radiation without a catalyst, did not significantly affect lignin content, biogas production, or methane yield. This method thus increases the energy valorisation of coffee waste while reducing the risk of caffeine being released into the environment as a micropollutant.
Artificial synapses based on transition metal oxides (TMO) are increasingly seen as promising for brain-inspired computing because their adjustable defect chemistry allows for synaptic data processing and nonvolatile memory storage functionality. Nevertheless, the inherent defect density in monolayer metal oxides frequently falls short of enabling stable and controllable synaptic functionality. In this study, a TiO2 and MoO3 bilayer memristor with a thickness approximately 65 nm was fabricated using radio-frequency (RF) magnetron sputtering conducted at ambient temperature. The device demonstrates stable nonvolatile resistive switching (RS) with promising spatial uniformity over 500th DC I-V cycles, coupled with a low read voltage (+0.7 V), extended retention (>104 s), and dependable performance at temperatures up to 150 °C. The conduction process is regulated by space-charge-limited current (SCLC), which is influenced by the managed oxygen vacancy levels in the TiO2/MoO3 bilayer. Furthermore, the device effectively replicates essential synaptic functions, including long-term potentiation/depression (LTP/LTD), paired-pulse facilitation/depression (PPF/PPD), and learning-forgetting behavior, thereby closely simulating biological synapses. A device-aware deep learning model further exhibits a classification accuracy of approximately 98% on the MNIST dataset. In summary, the proposed TiO2/MoO3 bilayer memristor with a MoN bottom electrode demonstrates stable resistive switching and reliable synaptic characteristics, highlighting its potential for future neuromorphic computing applications
Metal-organic frameworks (MOFs) have attracted significant interest owing to their versatility in addressing water pollution. Among them, UiO-66 has been recognized for its high surface area, tunable porosity, functionalization, structural flexibility, and chemical stability owing to its unique zirconium-terephthalate framework. UiO-66 has emerged as a robust photocatalyst for dye-polluted wastewater; however, the mechanistic understanding of how dye chemistry dictates its degradation pathway remains underexplored. This review evaluates UiO-66-based composites by bridging adsorption, bond-breaking chemistry, and electron-transfer dynamics with the inherent molecular features of cationic and anionic dye degradation. Instead of simply summarizing the structural changes, this review discusses how UiO-66 incorporated with various components, including metal oxides, silver plasmonic systems, COF hybrids, and membrane-supported architectures, plays an active role in initiating dye–catalyst interactions. These interactions are through π–π stacking, electrostatic attraction, dipole coupling, and surface functional groups, which initiate advanced pathways that synergistically promote electron–hole separation and radical generation. Across these systems, this review critically evaluates limitations, including photostability loss, metal leaching, recombination issues, pH instability, interface mismatch, and scalability constraints, which are often overlooked yet essential for practical deployment. This review offers a clear rationale for why some UiO-66 composites perform better by linking material composition to dye-specific mechanistic pathways. This work provides mechanistic, forward-looking design principles for next-generation photocatalysts from a critical, comparative perspective, with a focus on modular architectures, stabilized redox interfaces, and substrate-integrated platforms that bridge laboratory performance to scalable, real-world water purification applications.
Efficient and durable electrocatalysts are central to the realization of sustainable energy conversion and storage technologies, including water electrolyzers and metal–air batteries. Polymer-derived carbon (PDC) materials, obtained from biopolymers, synthetic polymers, and metal-organic polymers, have emerged as versatile platforms for multifunctional electrocatalysis. Their compositional diversity, controllable heteroatom doping, hierarchical porosity, and tunable electronic structure enable precise modulation of catalytic active sites and mass/electron transport pathways. This review establishes a unified framework that correlates precursor chemistry, carbonization pathways, and structural evolution with catalytic functionality toward oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). We systematically analyze synthetic strategies—including templating, in situ metal coordination, and polymer–metal hybridization—together with advanced characterization approaches that elucidate active-site configuration, defect chemistry, and interfacial phenomena. Particular emphasis is placed on electronic structure modulation, heteroatom coordination environments (e.g., M–N–C motifs), surface reconstruction under operating conditions, and pH-dependent stability mechanisms governing bifunctional and trifunctional performance. By integrating mechanistic insights with structure–activity relationships, this review defines key design principles for next-generation PDC-based electrocatalysts. Finally, the review outlines critical challenges related to scalability, durability under dynamic electrochemical conditions, and operando characterization, providing strategic directions for translating polymer-derived carbon systems into practical renewable energy technologies.
Achieving atomic-scale control of silicon thickness while preserving crystalline order is a major challenge for next-generation nanoelectronic devices. In this work, a CMOS-compatible top-down thinning strategy based on sequential rapid thermal oxidation and hydrofluoric acid etching (RTO/HF) is developed to controllably reduce the thickness of silicon-on-insulator (SOI) substrates down to the sub-nanometer regime.Spectroscopic ellipsometry (SE) and X-ray photoelectron spectroscopy (XPS) demonstrate reproducible thickness reduction from 7.05 nm down to 0.77 nm. Atomic force microscopy (AFM) measurements reveal that the surface roughness remains low and nearly unchanged during thinning, with root-mean-square (RMS) roughness values in the range of 0.3–0.4 nm. Most importantly, low-energy electron diffraction (LEED) measurements provide direct evidence that the long-range diamond-cubic order of Si(001) is preserved within the LEED probing depth even when the total silicon thickness is reduced below 1 nmThese results demonstrate that extreme top-down thinning can be achieved while maintaining structural and chemical integrity. The proposed RTO/HF approach therefore provides a scalable route toward ultra-thin crystalline silicon layers compatible with advanced CMOS device architectures.
