ACS Nanoscience Au最新文献

Electrochemical semihydrogenation (ESH) of alkynes to alkenes is an appealing technique for producing pharmaceutical precursors and polymer monomers, while also preventing catalyst poisoning by alkyne impurities. Cu is recognized as a cost-effective and highly selective catalyst for ESH, whereas its activity is somewhat limited. Here, from a mechanistic standpoint, we hypothesize that electron-deficient Cu can enhance ESH activity by promoting the rate-determining step of alkene desorption. We test this hypothesis by utilizing Cu–Ag hybrids as electrocatalysts, developed through a welding process of Ag nanoparticles with Cu nanowires. Our findings reveal that these rationally engineered Cu–Ag hybrids exhibit a notable enhancement (2–4 times greater) in alkyne conversion rates compared to isolated Ag NPs or Cu NWs, while maintaining over 99% selectivity for alkene products. Through a combination of operando and computational studies, we verify that the electron-depleted Cu sites, resulting from electron transfer between Ag nanoparticles and Cu nanowires, effectively weaken the adsorption of alkenes, thereby substantially boosting ESH activity. This work not only provides mechanistic insights into ESH but also stimulates compelling strategies involving hybridizing distinct metals to optimize ESH activity.

Although chemical promotion led to essential improvements in Cu-based catalysts for CO₂ hydrogenation to methanol, surpassing structural limitations such as active phase aggregation under reaction conditions remains challenging. In this report, we improved the textural properties of Cu/In₂O₃/CeO₂ and Cu/In₂O₃/ZrO₂ catalysts by coating the nanoparticles with a mesoporous SiO₂ shell. This strategy limited particle size up to 3.5 nm, increasing metal dispersion and widening the metal–metal oxide interface region. Chemometric analysis revealed that these structures could maintain high activity and selectivity in a wide range of reaction conditions, with methanol space-time yields up to 4 times higher than those of the uncoated catalysts.

The increasing use of silver nanoparticles (AgNPs) in consumer products has led to concerns about potential health risks after oral exposure as a result of the transformation and absorption in the gastrointestinal tract (GIT). However, the intricate condition of the GIT poses challenges in understanding the fate and toxicity of AgNPs as they traverse from the mouth to the rectum. For an in-depth understanding of the nanobio interactions, we employed a simulated digestion model to investigate alterations in the physicochemical properties of AgNPs in vitro. Meanwhile, we investigated the underlying toxicological mechanisms of digested AgNPs in enterocytes through metabolomics analysis. In contrast to route means that primarily apply salt solutions to mimic dietary digestion, this in vitro model is a semidynamic sequential digestion system that includes artificial oral, gastric, and intestinal fluids, which are similar to those under physiological conditions including electrolytes, enzymes, bile, pH, and time of digestion. Our results suggest that the formation of Ag–Cl and Ag–S species within the simulated digestion model can lead to an increase in the size of digested AgNPs and that the acidic condition promotes the release of Ag⁺ from particles. More critically, the presence of digestive enzymes and high concentrations of salt enhances the uptake of Ag by human colon enterocytes, ultimately promoting ROS generation and exacerbating cytotoxicity. Metabolomics analysis further reveals that the sequentially digested AgNPs may disorder lipid metabolism, including the biosynthesis of unsaturated fatty acids and arachidonic acid metabolism, thus increasing the possibility of ferroptosis activation in enterocytes. These findings offer significant insights into the fate and potential adverse effects of AgNPs in the GIT, providing important implications for assessing the health risks of AgNPs via oral exposure.

Biomolecular crystals can serve as materials for a plethora of applications including precise guest entrapment. However, as grown, biomolecular crystals are fragile in solutions other than their growth conditions. For crystals to achieve their full potential as hosts for other molecules, crystals can be made stronger with bioconjugation. Building on our previous work using carbodiimide 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide (EDC) for chemical ligation, here, we investigate DNA junction architecture through sticky base overhang lengths and the role of scaffold proteins in cross-linking within two classes of biomolecular crystals: cocrystals of DNA-binding proteins and pure DNA crystals. Both crystal classes contain DNA junctions where DNA strands stack up end-to-end. Ligation yields were studied as a function of sticky base overhang length and terminal phosphorylation status. The best ligation performance for both crystal classes was achieved with longer sticky overhangs and terminal 3′phosphates. Notably, EDC chemical ligation was achieved in crystals with pore sizes too small for intracrystal transport of ligase enzyme. Postassembly cross-linking produced dramatic stability improvements for both DNA crystals and cocrystals in water and blood serum. The results presented may help crystals containing DNA achieve broader application utility, including as structural biology scaffolds.

Significant endeavors have been dedicated to the advancement of materials for artificial photosynthesis, aimed at efficiently harvesting light and catalyzing reactions such as hydrogen production and CO₂ conversion. The application of plasmonic nanomaterials emerges as a promising option for this purpose, owing to their excellent light absorption properties and ability to confine solar energy at the nanoscale. In this regard, coupling plasmonic particles with molecular catalysts offers a pathway to create high-performance hybrid catalysts. In this review, we discuss the plasmonic–molecular complex hybrid catalysts where the plasmonic nanoparticles serve as the light-harvesting unit and promote interfacial charge transfer in tandem with the molecular catalyst which drives chemical transformation. In the initial section, we provide a concise overview of plasmonic nanomaterials and their photophysical properties. We then explore recent breakthroughs, highlighting examples from literature reports involving plasmonic–molecular complex hybrids in various catalytic processes. The utilization of plasmonic materials in conjunction with molecular catalysts represents a relatively unexplored area with substantial potential yet to be realized. This review sets a strong basis and motivation to explore the plasmon-induced hot-electron mediated photelectrochemical small molecule activation reactions. Utilizing in situ spectroscopic investigations and ultrafast transient absorption spectroscopy, it presents a comprehensive template for scalable and sustainable antenna-reactor systems.