Langmuir最新文献

The half reaction of oxygen evolution reaction (OER) has slow kinetics compared to the other reactions of hydrogen evolution reaction (HER) in electrocatalyst-based water splitting (WS) for hydrogen production. To improve the WS by an electrocatalyst, the use of spinel oxide based heterostructure (HS) catalysts supported by a carbon material is considered as a cost-effective strategy for the application of OER over noble metal catalysts. Here, for the first time, a novel WO₃/NiCo₂O₄ heterostructure coupled with MWCNT was synergistically interface engineered via an ultrasonication-assisted hydrothermal synthesis method to achieve an efficient electrocatalyst based oxygen evolution reaction (OER) due to their significant electrochemical activity of HS. The rational integration of WO₃ and redox-active NiCo₂O₄ with the highly conductive MWCNT framework results in a hierarchically porous heterointerface that promotes improved charge carrier transport, enhanced active site accessibility, and synergistic conductivity. The electrochemical results demonstrate the reduced overpotential of 323 mV at 10 mA cm^-2 for MWCNT@WO₃/NiCo₂O₄ with a Tafel slope of 123 mV dec^-1, a reduced charge transfer resistance of 2.5 Ω, and a large electrochemical double-layer capacitance of 48.9 mF cm^-2, outperforming its individual and WO₃/NiCo₂O₄ counterparts. Improved reaction kinetics, reduced energy barriers, and superior electrochemical durability of over 38 h underscore the effectiveness of this interface engineering strategy. These findings highlight the promise of MWCNT@WO₃/NiCo₂O₄ as a cost-effective, high-performance heterostructure for OER electrocatalysis in integrated water splitting and sustainable oxygen evolution reactions.

Spatially periodic patterns have been widely studied in chemical and biological systems, yet the emergence of hierarchical or multiscale architectures remains less explored experimentally, particularly in minimal material frameworks. In this work, it was observed in real time that a simple two-component solution consisting of methyltrimethoxysilane and phytic acid spontaneously forms macroscale hierarchical patterns upon exposure to air. Spectroscopic analyses reveal that chemical reactions initiated by environmental moisture drive sol-gel condensation and reaction-induced phase separation (RIPS), leading to the development of compositionally distinct microdomains. The resulting solid structures exhibit both periodic macroscopic wrinkle patterns and microscale anisotropic textures. The correlation between wrinkle spacing and film thickness suggests mechanical stress relaxation (buckling) during solidification, while the presence of localized contour-like features indicates anisotropic molecular ordering within the segregated domains. These findings show that hierarchical pattern formation can arise from the coupled effects of chemical reaction, phase separation, mechanical confinement, and molecular ordering in a minimal system. This platform provides an experimentally accessible route to study pattern formation mechanisms and may offer a basis for designing self-organized materials with multiscale architectures.

The highly efficient enrichment of Li⁺ and Cs⁺ from their low-concentration aqueous solutions is a crucial step for Lithium and Cesium clean production, as well as radioactive Cs⁺ safety remediation from water. The current adsorption and precipitation routes are high energy cost and environmental unfriendly. Electrochemical ion exchange route may serve as a promising alternative route. This study presents results of high efficient, multicycle Li⁺ and Cs⁺ enrichment from their low concentration solutions via intercalation and deintercalation in WO₃/GaAs composite electrode with Faraday efficiency above 99% and high intercalation capacities 7.25 mg/g for Li⁺ and 38.89 mg/g for Cs⁺, respectively. After six cycles, 95 and 90% capacities for Li⁺ and Cs⁺ still remained. Both enrichment efficiency and stability are higher than those of LiFePO₄ (LFP) and LiMn₂O₄ (LMO) under the same conditions. This route might provide a way for low-energy cost and highly efficient Li⁺ and Cs⁺ recovery from contaminated water.

The unique molecular structure of the surfactant is expected to produce solutions with distinctive rheological properties. A novel cationic surfactant, N¹,N¹,N¹,N³,N³-pentamethyl-N³-(3-(3-docosanamidopropanamido)propyl)propane-1,3-diammonium dibromide (C22-β-Ala-DQA), was synthesized. C22-β-Ala-DQA differs from conventional surfactants in that it contains a long saturated hydrophobic tail, two amide groups, and two quaternary ammonium head groups. It exhibits a low Krafft temperature (< 1 °C) and high aqueous solubility at 25 °C. When combined with sodium palmitate (SP), it forms transparent, viscoelastic solutions exhibiting pronounced elasticity at low concentrations across a broad range of molar ratios. Cryo-transmission electron microscopy (Cryo-TEM) imaging confirms the formation of ultralong wormlike micelles with a uniform cross-sectional diameter of ∼7 nm. Notably, the C22-β-Ala-DQA:SP system at a 1:1.5 molar ratio demonstrates significant thermo-thickening behavior between 30 and 80 °C. The zero-shear viscosity (η₀) of a 75 mM solution reaches a maximum of 632.5 Pa·s at 80 °C, which is unusually high for viscoelastic surfactant systems. This behavior is attributed to the dehydration of the large hydrophilic headgroup region of C22-β-Ala-DQA at high temperatures, which promotes further elongation of wormlike micelles. Surfactants with long saturated alkyl tails were used to prepare stable wormlike micellar solutions. These results provide valuable guidance for designing stable wormlike micellar systems using ultralong alkyl tails. Moreover, the proposed system shows potential for applications in fracturing fluids or other smart fluid technologies.

Membrane separation is an efficient and energy-saving technology for resource recovery, yet it faces challenges such as low separation efficiency, poor selectivity, and membrane fouling when complex acid leachates containing low-concentration platinum. To address these issues, this study reports a novel antifouling porous membrane based on a poly(vinylidene fluoride)/polyamidoamine matrix for the highly selective recovery of platinum. The membrane was fabricated by in situ cross-linking of N-allylthiourea to form a functional layer, followed by monoethanolamine/NaOH treatment to create a hydrophilic surface, resulting in the final PPAT membrane. The membrane exhibited an outstanding pure water flux of 636.54 LMH·bar^-1 and achieved a high Pt(IV) rejection rate of 96.11% at a trace concentration of 5 mg·L^-1. In a competitive filtration system, the PPAT membrane demonstrated superior selectivity for Pt(IV) over Cd(II), Cu(II), and Ni(II), with relative selectivity coefficients of 309.66, 114.08, and 106.4, respectively. Combined XPS and DFT calculations revealed that Pt(IV) capture was governed by electrostatic interactions, coordination, and hydrogen bonding. In addition, the XDLVO theory confirmed strong interfacial repulsion between the membrane surface and foulant, enabling the membrane to maintain a stable flux of 459.68 LMH·bar^-1 after three water-bovine serum albumin filtration cycles, highlighting its excellent long-term stability. This work provides a new strategy for designing multifunctional membranes and offers an alternative approach for highly efficient platinum recovery.

Optical tweezers (OTs) have emerged as a powerful tool for probing emulsion dynamics with single-droplet precision, enabling quantitative analysis of interfacial interactions. Recent OT studies have systematically elucidated the critical factors governing emulsion stability, including ionic strength, pH, surfactant architecture, temperature, and photo/gas stimuli. Parallel advances in optofluidic control demonstrate that light-driven droplet rotation-achieved through angular momentum transfer and liquid crystal molecular reorientation represents a transformative approach for active soft matter manipulation. In this review, we conduct a systematic evaluation of OT systems, encompassing both instrumental configurations and cost-benefit analyses to assess their practical feasibility. The review critically examines the unique capabilities of OTs in emulsion research-including unprecedented spatial resolution and quantitative force measurement at the single-droplet level while addressing current limitations in throughput and operational complexity. Looking forward, the synergistic integration of OT technology with microfluidic platforms and machine learning algorithms is also presented.

Crystallization of two distinct colloidal building blocks into binary nanoparticle superlattices (BNSLs) offers an innovative strategy for preparing advanced functional materials with integrated and remarkable properties, enabling various applications in optoelectronics, catalysis, and sensing. The symmetries and architectures of binary superlattices critically govern their intrinsic properties and are primarily dictated by thermodynamically stable and favorable structures. However, the construction of kinetically trapped metastable superlattices in nonequilibrium phases remains a formidable challenge. Here, we demonstrate a pathway-directed preparation of BNSLs crystallized from polymer-tethered gold nanoparticles at the two-dimensional interface, where internal symmetries and stoichiometries are readily modulated through thermodynamic and kinetic assembly pathways. Unlike the conventional hexagonal packing found in the lowest-energy state, achieving specific BNSLs with AB₆ and AB, stoichiometries requires precisely steering the crystallization process into a kinetically controlled pathway. Moreover, the effective size ratio parameter is proposed to quantitatively evaluate the influence of the effective size of each constituent on the final symmetry of the BNSLs, providing guiding and significant phase diagrams of the acquired architectures. This pathway-controlled approach enables the formation of BNSLs with symmetries challenging to achieve via traditional thermodynamic control, offering possibilities for developing multifunctional superlattice materials.

The centrosymmetric diamond structure of bulk silicon inherently lacks second-order nonlinearity, thereby limiting its applicability in photonic devices. In this work, we systematically investigate the second-harmonic generation (SHG) responses on Si(001) surfaces by employing symmetry-breaking strategies through surface engineering and molecular functionalization using first-principles density functional theory calculations. Four reconstructed Si(001) surfaces, including (1 × 1), (2 × 1), (1 × 2), and (2 × 2), were systematically examined. Among them, the (2 × 2) configuration exhibits the highest stability, while the (1 × 1) surface shows the strongest SHG activity. The simulated polarization-dependent SHG images reveal distinct symmetries of the (1 × 1) surface, whereas the other surfaces exhibit similar symmetric characteristics for both parallel and perpendicular components. Furthermore, 14 adsorption structures of ethylene on the Si(001)-(2 × 2) surface were examined, including both parallel and bridging configurations. The presence of adsorbed C₂H₄ significantly modulates the SHG response of the Si(001)-(2 × 2) surface. Specifically, most parallel adsorption geometries suppress the SHG intensity, while bridging configurations enhance the nonlinear optical activity of the surface. Notably, polarization-dependent SHG patterns are highly sensitive to molecular adsorption configurations, demonstrating that SHG spectroscopy is a powerful tool for characterizing surface reconstructions and interfacial molecular arrangements.

Defects play a crucial role in determining the properties of nanomaterials, yet their contribution to chemical reactivity - particularly in the context of assembled atomic clusters - remains poorly understood. In this work, we reveal how the introduction of defect states fundamentally alters the chemical reactivity landscape of atomically precise nanocluster assemblies. We show that uric acid (UA) engages in distinct chemical interactions with Mn²⁺-doped Zn-Au nanocluster assemblies (Mn-Zn Au NCs), compared to Zn-Au NCs assemblies lacking Mn²⁺ defects. While Zn-Au NCs responds to UA with enhanced fluorescence, Mn-Zn Au NCs exhibit selective quenching of the Zn-Au NC emission while retaining the Mn²⁺-related emission, thereby producing a concentration-dependent ratiometric signal detectable down to 0.566 ± 0.001 μM. The dual-emission behavior also drives a continuous shift in chromaticity coordinates, offering optical readout. Mechanistic analysis reveals that UA coordinates surface Zn²⁺ ions through specific functional groups, with binding governed by chelating-site arrangement and pK_a-dependent ionization states at near-physiological pH. This coordination enables energy transfers to surface Mn²⁺, leading to nonradiative dissipation and selective modulation of emission pathways. These findings establish Mn-Zn Au NCs as a unique nanocluster-based platform in which defect states dictate not only photophysical outcomes but also chemical reactivity, highlighting new opportunities for defect-engineered, ratiometric sensing at the nanoscale.

Solar steam generation is widely recognized as a sustainable and cost-effective technology for seawater desalination and wastewater purification, offering an efficient solution to mitigate global water scarcity. Herein, a populus-inspired aerogel evaporator composed of hydrophilic poly(vinyl alcohol) (PVA) and carbonized straw was fabricated through a directional freezing strategy. The incorporation of carbonized straw significantly enhanced the solar absorption of the evaporator to 95.1% while effectively reducing the material cost. Notably, the custom-designed vertically aligned channels in the evaporator significantly reduce water transport resistance, thereby enabling more rapid and efficient water delivery. Benefiting from its precisely tailored structure, the aerogel evaporator achieves a water evaporation rate of up to 2.6 kg m^-2 h^-1 and a solar energy conversion efficiency as high as 98.2% under 1-sun illumination (1 kW m^-2). Moreover, the evaporator exhibits excellent cycle stability and high practical applicability. This work presents a promising and practical strategy for fabricating highly efficient, eco-friendly, and cost-effective aerogel evaporators, demonstrating significant potential for real-world applications in seawater desalination and wastewater treatment.