Langmuir最新文献

Photocatalytic H₂O₂ productionoffers a promisingsunlight-driven pathway toward sustainable oxidant synthesis, butits performance is constrained by slow interfacial redox kinetics,insufficient proton availability, and rapid recombination of photoinducedcarriers. Herein, g-C₃N₄ was prepared by thermallycalcining melamine and ammonium fluoride at equal mass, and CuO@g-C₃N₄ composites were subsequently constructed viaultrasound-assisted dispersion and hydrothermal treatment. The morphology,phase structure, surface chemistry, optical response, charge-transportbehavior, carrier lifetime, and electronic structure were investigatedby SEM-EDS, XRD, XPS, BET, UV–vis DRS, PL, photoelectrochemicalmeasurements, TPV, and DFT simulations. Benefiting from optimizedinterfacial electronic interaction, the 30% CuO@g-C₃N₄ composite delivered H₂O₂ generationproductivity reaching 2120 μmol g^–1 h^–1 in air using a water/isopropanol mixed solvent (9:1,v/v), 3.66 times the value for pristine soft-templated g-C₃N₄. Under pure O₂, the productivity furtherincreased to 3700 μmol g^–1 h^–1 with cycling durability. PL, EIS, and TPV analyses confirm thatCuO incorporation suppresses charge recombination, promotes carriertransport, and extends the carrier lifetime from 414 to 7117 μs.Combined evidence from XPS, band-structure analysis, photoelectrochemicalmeasurements, reactive-species quenching, DMPO-trapping EPR spectroscopy,and DFT calculations reveals that interfacial chemical bonding constructsa type-II heterojunction, enabling directional charge migration andstabilizing •O₂^– intermediatesfor a successive one-electron ORR pathway toward H₂O₂ evolution. Overall, this study provides mechanistic insightinto interfacial charge regulation in CuO@g-C₃N₄ heterojunctions and offers guidance for the rational developmentof efficient photocatalysts.

The escalating global demand for lithium, driven by therapid growthof production of electric vehicles and portable electronics, requiresthe development of selective and scalable extraction technologiescapable of recovering lithium from complex liquid resources such asgeothermal-, oilfield-, or low-grade salar brines. This study presentsthe development and characterization of a novel composite membraneadsorbent based on a monoclinic β-Li₂TiO₃ (LTO) lithium-ion sieve embedded within a poly(vinyl chloride) (PVC)and silica (SiO₂) matrix. The incorporation of SiO₂ as a structural component enhances mechanical stability,processability, and wettability of the membrane enabling fabricationvia industrially scalable extrusion and calendaring techniques andpromoting contact of the Li-bearing brine with LTO particles insidethe pore system of the membrane. Three membrane compositions withvarying SiO₂:LTO ratios (50:50, 40:60 and 30:70 wt %) weresystematically investigated. Among the investigated compositions,the 40% SiO₂-60% LTO membrane achieved the highest equilibriumadsorption capacity of approximately 37 mg Li⁺ g^–1 HTO at 45 °C from a dilute feed solution (C₀ = 100 mg L^–1), consistent with endothermic,chemisorption-controlled Li⁺/H⁺ exchange kineticsbest described by the pseudo-second-order model. Selectivity evaluationin a mixed-cation solution simulating geothermal brine compositionyielded a Li⁺ distribution coefficient (K_d) of 304 mL g^–1, with separation factorsof 12 over Na⁺ and Mg²⁺, and 8 over K⁺. The membrane retained stable adsorption capacity over several consecutiveadsorption–desorption cycles, confirming good chemical andstructural stability. These results demonstrate the potential of PVC/SiO₂/LTO composite membranes as a promising, cost-effective, andindustrially scalable platform for selective lithium recovery fromcomplex brines.

Zirconium-based metal–organicframeworks have emerged aspromising materials for the capture and detoxification of chemicalwarfare agents, but the molecular mechanism by which a hierarchicalMOF differentiates a hydrophobic reactant from its oxidized productremains incompletely understood. Here, we use molecular dynamics simulations,grand-canonical Monte Carlo adsorption calculations, and periodicdensity functional theory to examine the dual-hosting behavior ofNU-1000 toward sulfur mustard (HD) and mustard sulfoxide (HDO). Ratherthan treating NU-1000 only as an adsorbent or oxidation catalyst,we resolve how its internal micropore, mesopore, and c-pore interfacesimpose distinct confinement environments on reactant and product species.Density functional theory (DFT) calculations show that HD binds mostfavorably in the c-pore region, with a binding energy of approximately−12.5 kcal/mol, and similarly favorable stabilization in confinedmicropore environments, whereas substantially weaker binding is observedin the mesopore. Molecular dynamics simulations also reveal sharplydifferent pore residence patterns: HD localizes predominantly in micropores,occupying this region for ∼80% of the trajectory, while HDOsamples larger pore environments more broadly, with ∼45% mesoporeand ∼34% c-pore occupancy. This pore-selective behavior persistsunder mixed HD/HDO coadsorption conditions, demonstrating that reactant–productdifferentiation is intrinsic to the NU-1000 pore network rather thanan artifact of isolated single-component simulations. Radial distributionfunctions further show that HD is stabilized by dispersion-dominatedconfinement and weak halogen–hydrogen contacts, whereas HDOis governed by more localized, orientation-dependent interactionswith hydrated zirconium node sites. These interaction differencesproduce a pronounced transport asymmetry, with HDO exhibiting a self-diffusioncoefficient of 10.6 ± 2.11 × 10^–10 m²/s compared with 0.5 ± 0.09 × 10^–10 m²/s for HD at comparable loading. The results identifyNU-1000 as a dual-function molecular host that couples reactant retentionwith product mobility, providing an interface-level mechanism relevantto selective CWA detoxification and confined transport in hierarchicalporous catalysts.

The rebound behavior of dropletsimpacting superhydrophobicsurfacesis ubiquitous in natural and industrial processes and is closely associatedwith a wide range of practical applications. In special applicationscenarios such as aircraft and high-altitude equipment, surfaces areoften subjected to both vibration and low pressure. However, existingstudies are mostly based on atmospheric pressure or stationary surfaces.It remains unclear how moderate low pressure and external vibrationjointly affect droplet spreading. In this work, high-speed photographywas employed to first investigate the impact dynamics of dropletson a stationary superhydrophobic surface under low pressures (97,74.6, and 60 kPa). The influence of pressure on the spreading processwas examined. Subsequently, at 60 kPa, the effects of vibration phase,frequency, and amplitude on droplet impact were studied. The resultsshow that the maximum spreading coefficient increases gradually withdecreasing pressure. This can be attributed to the reduction of gas-phasedissipation during droplet spreading under low pressure. Meanwhile,vibration introduces an additional phase-dependent energy input mechanism.The maximum spreading coefficient exhibits a pronounced periodic variationwith the initial phase angle. Moreover, as the vibration frequencyand amplitude increase, the fluctuation of the maximum spreading coefficientwith phase becomes more significant. Based on energy conservationanalysis, an empirical mathematical model was developed for the maximumspreading diameter of a droplet impacting a vibrating superhydrophobicsurface under low pressure. The model elucidates the regulatory mechanismsby which pressure and vibration modulate energy input and dissipationduring impact. This study contributes to understanding the interfacialdynamics of droplet impact under coupled low-pressure and vibrationconditions, and provides useful insights into droplet impact behaviorunder relevant environmental conditions.

For the eco-friendly asphalt pavements with NO_x degradation performance, TiO₂@CoAl-LDHswere preparedand applied as asphalt modifiers. X-ray diffraction (XRD) and X-rayphotoelectron spectroscopy (XPS) indicated that TiO₂ wasuniformly loaded onto the surface of the CoAl-LDHs, and TiO₂@CoAl-LDHs have been successfully synthesized. The integration ofTiO₂ and CoAl-LDHs reduced the energy barrier for electron–holepair formation upon light irradiation, resulting in the stronger absorbanceof TiO₂@CoAl-LDHs in both ultraviolet and visible lightranges. After combining TiO₂ with CoAl-LDHs, the photogeneratedelectron transfer and separation efficiency of TiO₂@CoAl-LDHswere significantly enhanced, and the recombination of electron–holepairs was concomitantly suppressed. Compared with TiO₂ andCoAl-LDHs, TiO₂@CoAl-LDH-modified asphalt exhibited strongerinteraction with NO_x. Meanwhile, NO_x diffused more easily and had a larger penetrationproportion in TiO₂@CoAl-LDH-modified asphalt. All of thesecontributed to better NO_x photocatalyticdegradation capability of TiO₂@CoAl-LDH-modified asphalt.This study promotes the development of eco-friendly asphalt pavements.

Inducing and stabilizing mesoscale structures in fullymisciblemolecular liquids remains challenging because local heterogeneityis usually transient and rapidly averaged out. Here, we show thatperiodic thermal oscillation drives a 50% (v/v) ethanol–watermixture along a traceable nonequilibrium ordering pathway from transientethanol–water clusters to kinetically stabilized soft aggregates.The system evolves from initial clusters to water-containing dropletsas liquid–liquid microphase-separated intermediates, then toethanol-rich acicular flakes, and ultimately to micron-scale flake-stackedaggregates. Fluorescence spectroscopy, two-dimensional correlationanalysis, and nuclear magnetic resonance reveal that this processbegins with perturbation and relaxation of the water-dominated hydrogen-bondnetwork, proceeds through a water–ethanol coassociated intermediate,and culminates in ordered ethanol aggregates. Thermal analysis andin situ Raman spectroscopy further show progressive stabilizationacross the structural hierarchy. These findings demonstrate that periodicthermal forcing can amplify transient molecular heterogeneity intomesoscale soft structures in a fully miscible liquid, providing akinetic perspective on nonequilibrium cluster amplification and microphase-separatedaggregate formation in hydrogen-bonded molecular systems.

Flexible perovskite solar cells (f-PSCs) suffer fromburied-interfaceenergy-level mismatch, severe interfacial recombination, and inefficientcharge transport, which limit both device efficiency and stability.Herein, we develop a synergistic strategy by integrating a trimethoxy[3-(phenylamino)propyl]silane (TEPAPS) dipole interlayer with conductive SnO_x/C nanofibers (NFs) to simultaneously regulate theburied interface and perovskite bulk. The TEPAPS interlayer reducesthe work function, improves energy-level alignment, and passivatesinterfacial Pb²⁺ defects. Meanwhile, TEPAPS-modified SnO_x/C NFs act as conductive one-dimensionalframeworks and crystallization templates, promoting grain growth,reducing defect density, and establishing efficient charge-transportpathways throughout the perovskite layer. As a result, nonradiativerecombination is effectively suppressed and carrier extraction isaccelerated. Owing to the synergistic effects of interfacial dipolemodulation and conductive nanofiber engineering, the optimized rigiddevice and flexible devices achieve power conversion efficiencies(PCEs) of 24.11% and 21.63%, respectively. Moreover, the flexibledevice retains 88.2% of its initial efficiency after 600 bending cycles.This work provides an effective approach for simultaneously engineeringburied-interface energetics and bulk charge transport for high-performanceflexible perovskite photovoltaics.

The removal of agrochemical contaminantsfrom water andsoil isa major challenge in environmental remediation. Adsorption-based treatmentsare widely used for contaminant removal due to their efficiency, scalability,and relatively low cost, making the understanding at the molecularlevel of pesticide–surface interactions essential for improvingremediation strategies. Here, molecular dynamics (MD) simulationswith adaptive biasing force (ABF) were used to evaluate the adsorptionfree energies of several well-known agrochemicals, including glyphosate,atrazine, chlorpyrifos, aminomethylphosphonic acid (AMPA), glufosinate,rotenone, and paraquat, on graphene, graphene oxide, and hydroxylatedsilica surfaces. These materials represent model systems for the carbonaceousand mineral components commonly found in environmental matrices. MDsimulations reveal systematically stronger adsorption on graphene-basedmaterials (≈ −3 to −13 kcal/mol), driven primarilyby dispersion and π-surface interactions, resulting in particularlyhigh affinity for aromatic and compounds with low polarity such asatrazine, chlorpyrifos, and rotenone. In contrast, adsorption on hydroxylatedsilica is substantially weaker (≈ −1 to −3 kcal/mol)and reflects competition between hydrogen bonding, electrostatic interactionswith surface silanol groups, and interfacial hydration. Polar molecules,such as glyphosate, glufosinate, and AMPA, interact mainly throughhydration-mediated mechanisms, while other compounds, such as paraquat,exhibit intermediate behavior due to their planar aromatic structure.Overall, these findings provide a thermodynamic rationale at the molecularlevel for the role of soil organic carbon in limiting pesticide leachingand suggest that carbon amendments designed with complementary mineralphases may enhance the retention capacity of natural substrates.

The need to develop novel and sustainable media withoutusing conventionalsurfactants has driven the development of surfactant-free microemulsions(SFMEs). Deep eutectic solvents (DESs) and ionic liquids (ILs) aregreat alternatives to conventional organic solvents, using which SFMEscan be prepared. Herein, an SFME has been prepared using a DES basedon the natural components L-arginine and lactic acidas the polar phase; 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonylimide),a hydrophobic ionic liquid (HIL), as the nonpolar phase; and ethanolas an amphiphile. The SFME has been duly characterized to establishits structural organization at the molecular level by employing varioustechniques such as conductivity measurements, dynamic light scattering(DLS), small-angle X-ray scattering (SAXS), Fourier-transform infrared(FTIR) spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy.Investigations on the internal structure of the SFME reveal that ethanoldoes not form an effective barrier layer, instead, it forms hydrogen-bonded(H-bonded) solvent domains interacting mainly withDES nanoclusters, followed by the imidazolium cation at the HIL polar–nonpolarinterface. The presence of such nanoinhomogeneity at the solvent interfacesimparts an associative nature to microemulsion droplets, which hasnever been reported before. The prepared SFME has been employed asa nanoreactor to explore the catalytic activity of cytochrome-c (Cyt-c).Variation in the phase composition of the SFME markedly affects theenzyme activity, wherein the DES-in-HIL phase of the SFME offers anoptimal environment for ∼6.5 folds enhancement in enzyme activityas compared to that observed in buffer. The favorable cation-πand H-bonding interactions of arginine and lacticacid at the DES–ethanol interface, along with ethanol clusters,stabilize the structure of Cyt-c. This study provides new insightsinto the structural and functional aspects of SFMEs, which will encouragethe development of new SFME systems for a broad spectrum of biocatalyticapplications, along with the utilization of nanoinhomogeneity forconstructing hierarchically self-assembled materials.