Journal of Colloid and Interface Science最新文献

Step-scheme (S-scheme) heterojunction has attracted much attention in the design of heterostructures for photocatalysts. In this study, we successfully utilized the principle of electrostatic self-assembly to load ultrathin ZnIn₂S₄ nanosheets onto snowflake-like Cu₂S using a simple grinding method, and synthesized Cu₂S/ZnIn₂S₄ S-scheme heterojunctions according to the different work functions (Φ). At the optimal Cu₂S loading ratio (5 wt%), the hydrogen yield of the Cu₂S/ZnIn₂S₄ composites reaches 5.58 mmol·h^-1·g^-1, which is 5.12 times higher than that of pure ZnIn₂S₄ (1.09 mmol·h^-1·g^-1). The apparent quantum efficiency (AQE) of the Cu₂S/ZnIn₂S₄ composites reaches 5.8 % (λ = 370 nm), which is an improvement compared to pure ZnIn₂S₄ (2.7 %). The AQE of pure ZnIn₂S₄ is 0.4 %, while the AQE of Cu₂S/ZnIn₂S₄ composites is enhanced to 1.0 % at λ = 456 nm. The heterojunction interface of Cu₂S and ZnIn₂S₄ builds a built-in electric field (IEF), which greatly reduces the recombination rate of photogenerated electrons and holes, retains highly reduced photoelectrons in the conduction band (CB) of ZnIn₂S₄. The snowflake structure of Cu₂S effectively increases the active sites and specific surface area, and improves the light absorption. This work opens a new avenue for designing photocatalysts, synergizing energy development and protecting the environment.

Dynamic fluorescent switches with multiple light outputs offer promising opportunities for advanced security encryption. However, the achievement of dynamic emission, particularly when based on the timing of external stimuli, continues to present a significant challenge. Herein, a unique dynamic fluorescent switch was developed by integrating spiropyran molecules (SP) into a core-shell structure (SiO₂@Tb-MOF). The core-shell structure, derived from lanthanide complexes and silica microspheres, was synthesized under solvothermal conditions. This structure not only preserves the green fluorescence emission of Tb-MOF, but also results in a substantial specific surface area and mesoporous pore size from SiO₂, which is advantageous for incorporating SP molecules to create a dynamic fluorescent switch, SP ⊂ SiO₂@Tb-MOF. Upon exposure to ultraviolet light, SP gradually transitions into the merocyanine form (MC), displaying a pronounced absorption band at approximately 550 nm. Concurrently, a fluorescence resonance energy transfer (FRET) process is initiated between Tb³⁺ and the merocyanine isomers. With prolonged exposure to UV light, the fluorescence color shifts progressively from green to red, facilitated by the ongoing FRET process. Moreover, SP ⊂ SiO₂@Tb-MOF is doped with polydimethylsiloxane to fabricate a film. Utilizing time-dependent fluorescence, dynamic encryption patterns and advanced information encryption were investigated. This work provides a design basis for how to better construct core-shell structures and combine them with SP molecules to prepare dynamic fluorescent materials, and paves a way for constructing advanced encryption materials with higher safety requirements.

It is critical and challenging to develop highly active and low cost bifunctional electrocatalysts for the hydrogen/oxygen evolution reaction (HER/OER) in water electrolysis. Herein, we propose cerium-vanadium-based hollow nanopillar arrays supported on nickel foam (CeV-HNA/NF) as bifunctional HER/OER electrocatalysts, which are prepared by etching the V metal-organic framework with Ce salt and then pyrolyzing. Etching results in multidimensional optimizations of electrocatalysts, covering substantial oxygen vacancies, optimized electronic configurations, and an open-type structure of hollow nanopillar arrays, which contribute to accelerating the charge transfer rate, regulating the adsorption energy of H/O-containing reaction intermediates, and fully exposing the active sites. The reconstruction of the electrocatalyst is also accelerated by Ce doping, which results in highly active hydroxy vanadium oxide interfaces. Therefore, extremely low overpotentials of 170 and 240 mV under a current density of 100 mA cm^-2 are achieved for the HER and OER under alkaline conditions, respectively, with long-term stability for 300 h. An electrolysis cell with CeV-HNA/NF as both the cathode and anode delivers a small voltage of 1.53 V to achieve water electrolysis under 10 mA cm^-2, accompanied by superior durability for 150 h. This design provides an innovative way to develop advanced bifunctional electrocatalysts for overall water electrolysis.

Shadow sphere lithography (SSL) offers unparalleled advantages in fabricating complex nanostructures, yet optimizing these structures remains challenging due to vast parameter spaces. This study presents a general optimization framework for SSL-fabricated nanostructures, demonstrated through chiral metamaterials. The approach combines a custom SSL program, a novel mathematical model for eliminating redundant structures, and machine learning (ML) analysis of finite-difference time-domain (FDTD) simulations. Applied to rotated nanohole arrays (RHAs), this framework efficiently navigates a 7200-structure parameter space, identifying optimal configurations with circular dichroism (CD) and g-factor up to 3.23˚ and 0.28, respectively. Experimental validation of optimized RHAs shows good agreement with predictions, exhibiting twice the chiral response of random configurations. Notably, the framework reduces the dataset by 86%, significantly decreasing computational costs. This optimization framework enables faster, more systematic, and more efficient optimization of structures manufactured using SSL, potentially accelerating discoveries in nanophotonics, plasmonics, and chiral sensing applications.