Langmuir最新文献

The development of efficient bifunctional catalysts to improve the kinetics of oxygen electrode reactions is a critical challenge in realizing high-performance, long-life lithium-oxygen batteries. Herein, TiC was successfully synthesized via a molten salt electrolysis method, followed by the preparation of a series of TiC-derived carbon (TiC-xCDC, x = 10, 30, 60) composites by adjusting the electrolytic time after electrode exchange. The formation of derived carbon effectively addresses the issue of TiC agglomeration and significantly enhances the electrical conductivity of the composite. Particularly, the TiC-30CDC composite not only exhibits a large specific surface area and an abundant mesoporous structure, providing ample storage space for discharge products, but also facilitates ion and electron transport efficiency. Moreover, the electrochemical stability and robust catalytic performance of TiC further promote the kinetics of the oxygen electrode reaction, resulting in excellent electrochemical performance in lithium-oxygen batteries. At a current density of 500 mA g^-1, the TiC-30CDC cathode demonstrates an impressive specific discharge capacity of up to 15,081.9 mAh g^-1. At the same current density with a defined specific capacity of 1000 mAh g^-1, the cathode can operate stably for 430 cycles while maintaining low discharge/charge overvoltage levels (2.49 V/4.45 V) even after nearly 1800 h of cycling. The air electrode prepared through molten salt electrolysis offers an innovative and feasible approach for the design and mass production of other metal-air cathodes due to its significant cost-effectiveness and environmental friendliness.

Highly sensitive lateral flow immunoassays (LFIAs) are essential for various point-of-care applications, and gold nanoparticles (Au NPs) are by far the most commonly used labels. However, conventional LFIAs often suffer from high detection limits (LOD) or low sensitivity. In this study, we investigated three strategies to enhance the sensitivity of LFIAs by improving the peroxidase-mimicking (POD) activity of Au NPs. The POD activity of unmodified Au NPs was negligible (<0.01 units/mg, U/mg). The first strategy involved coupling Au NPs with horseradish peroxidase (HRP), which increased the POD activity to 65 U/mg. The second approach involved forming a thin palladium or iridium shell on Au NPs, which elevated the POD activity to 0.69-0.71 U/mg. The third strategy involved binding mercury ions (Hg²⁺) to Au NPs, resulting in a POD activity of up to 3 U/mg. Finally, we developed a simple quantitative model to estimate the LOD of LFIAs based on the POD kinetic parameters. Using Au-HRP conjugates, we demonstrated that the experimentally measured LOD was consistent with the calculated values. The developed model provides a framework for evaluating LFIAs with catalytic signal amplification and can be used to guide the development of highly sensitive assays.

Numerous experimental results have demonstrated that Pickering emulsions stabilized by modified silica nanoparticles exhibit excellent performance in enhanced oil recovery. This study investigates the microcosmic mechanism of emulsion stability formed by three typical silica nanoparticles (hydrophilic SiO₂ (HSO), hydrophobic SiO₂ (LSO), and Janus SiO₂ (JSO)) by using experiments and molecular dynamics simulations. Based on the results of the interfacial tension and emulsification index (EI) measurements, JSO exhibits the greatest interfacial activity, whereas LSO possesses a similar ability to stabilize emulsions as JSO. Then, the number density distribution and solvent-accessible surface area (SASA) are calculated to explore in detail the interfacial distribution of nanoparticles affected by oil components in the aqueous phase. The mechanism of nanoparticle stabilization emulsion is further investigated via the radial distribution function (RDF), interaction energy, and independent gradient mode based on Hirshfeld partition (IGMH), which is verified via steered molecular dynamics (SMD) simulations. It is found that the more intensive hydrophobic effect among nanoparticles in comparison to the weaker interaction between asphaltenes and nanoparticles should be responsible for the special "nanoparticles channel" formed by LSO, which is beneficial to emulsion stability. The interfacial membrane barrier of JSO, caused by van der Waals interactions and weak hydrogen bonds with asphaltenes, significantly improves the stability of the emulsion. This work is of great significance to the in-depth understanding of the mechanism by which modified nanoparticles stabilize emulsions.

Microplastics (MPs) originate from industrial production of <1 mm polymeric particles and from the progressive breakdown of larger plastic debris. Their environmental behavior is governed by their interfacial properties, which dominate due to their small size. This Perspective highlights the complex surface chemistry of MPs under environmental stressors and discusses how physical attributes like shape and roughness could influence their fate. We further identify wastewater treatment plants (WWTPs) as critical hotspots for MP accumulation, where the MPs are inadvertently transferred to sewage sludge and reintroduced into the environment. We emphasize the potential of colloid and interfacial science not only to improve our fundamental understanding of MPs but also to advance mitigation strategies in hotspots such as WWTPs.

Molybdenum disulfide (MoS₂) has a typical layered structure and is widely used in the lubrication field. However, its nanosheets are difficult to disperse and prone to agglomeration in lubricating oil, which makes it challenging to achieve ultralow friction in the atmospheric environment and restricts its practical applications. Therefore, it is of great significance to solve the disperse and agglomeration problems of MoS₂ to realize ultralow friction. In this paper, MoS₂ nanosheets synthesized by the hydrothermal method were taken as the target material, and tremella-like MoS₂ nanospheres were successfully prepared by laser irradiation in liquid. This technique realizes the reshaping of the morphology of MoS₂ under normal temperature and pressure and is simple, clean, and efficient. Importantly, these unique tremella-like nanospheres, as additives for glycerol, can not only effectively inhibit the aggregation of nanomaterials, possessing excellent dispersion stability and good wetting properties, but also significantly reduce the friction and the wear rate, enabling the system to achieve long-term stability and ultralow friction in the atmospheric environment. The analysis of the worn surfaces indicates that the effective formation of the MoS₂ tribofilm and its self-storage lubrication characteristics are the key factors for achieving ultralow friction. This research promotes the application of ultralow friction materials in the engineering field and provides a theoretical basis for the development of new lubricants.