ACS Materials Letters最新文献

Heteronuclear dual-atom catalysts (DACs) have attracted considerable interest due to their synergistic effects. However, controlling the spatial distribution of bimetallic atoms and developing a comprehensive theoretical framework remain challenging. Here, we systematically investigate long-range-coupled FeM DACs using density functional theory (DFT) calculations to identify hetero-FeZn sites with optimal local electron density and geometry. We introduce a strategy to create precisely ordered sites on hierarchically porous nitrogen-doped carbon (FeZn-NC). Establishing a heterogeneous intermetallic precursor promotes the desired atomic pairs through microstructural inheritance. DFT and experiments confirm synergistic FeN₄–ZnN₄ interactions induce asymmetric charge distributions that balance oxygen intermediate adsorption/desorption. Consequently, FeZn-NC exhibits extraordinary ORR activity with a high half-wave potential of 0.91 V and a mass activity of 32.52 A mg^–1. Moreover, it achieves high discharge performance and excellent durability exceeding 1300 h in zinc–air batteries (ZABs). More importantly, this prefabricated bimetallic spacing strategy demonstrates versatility for preparing various diatomic sites.

Artemisinin derivatives show antitumor potential via their peroxide bridge, but dihydroartemisinin (DHA) suffers from poor solubility and limited targeting. In this study, inspired by artesunate (ART), we synthesized two derivatives, DHA-CC and DHA-SS, and prepared their PEGylated nanoassemblies (pNAs) using DSPE-PEG_2K to enhance their in vivo stability and prolong circulation. Between the two derivatives, DHA-SS pNAs, with their unique disulfide bond structure, demonstrated superior stability, circulation time, and tumor accumulation. Importantly, DHA-SS pNAs exhibited specific responsive drug release under the reductive tumor microenvironment (TME), thereby achieving a favorable balance between systemic stability and efficient activation at the tumor site. In vitro and in vivo evaluations demonstrated that DHA-SS pNAs have higher reactive oxygen species (ROS) generation, greater cytotoxicity, and enhanced antitumor effects without evident systemic toxicity. Overall, these findings demonstrate that this rational structural modification offers a promising strategy for advancing artemisinin-based antitumor therapies toward clinical translation.

Two-dimensional (2D) MXenes are synthesized by a top-down etching of MAX phases, which could generates surface metal vacancies. However, the nature and impact of these vacancies remain unclear. We combine atomic force microscopy (AFM) nanoindentation, electrochemical studies, and density functional theory (DFT) to examine how titanium vacancies (V_Ti) influence the mechanical and electrochemical behavior of Ti₃C₂T_x MXene. A moderate level of V_Ti increases the in-plane modulus of monolayer Ti₃C₂T_x from 324 ± 44 to 432 ± 53 N m^–1 and enhances the fracture force by ∼60%. The calculated effective Young’s modulus of 432 ± 53 GPa is among the highest for 2D materials. Also, moderate V_Ti improves the electrochemical performance of MXenes. DFT indicates that partial occupation of V_Ti by H₂O, H⁺, or Li⁺ redistributes charge and increases lattice stiffness, while coalescence impedes electron transport and suppresses capacitance at higher V_Ti. This study deepens the understanding of vacancies in MXenes and provides a route to tune their properties.

The separation of hexane isomers is crucial for producing high-octane gasoline but is challenged due to their similar properties. Herein, a biomimetic separation strategy was presented inspired by the molecular recognition mechanism of enzyme active sites to achieve hexane isomer separation. Through rational design of pore geometry and chemical environment, Ni-pca-pyz, with the precision of biological systems, was developed. The framework features optimized aperture size (∼5.2 Å) and tailored surface functionality, enabling perfect discrimination between mono- and dibranched isomers. This biomimetic design resulted in excellent separation performance, with breakthrough experiments directly producing high-purity dibranched isomers with research octane numbers (RON) above 90. Theoretical calculations confirmed that the exceptional separation performance stems from the synergy between steric exclusion and favorable host–guest interactions, effectively replicating the lock-and-key recognition mechanism observed in enzymatic systems. This work establishes a biomimetic paradigm for advanced, energy-efficient separation materials.

The widespread adoption of materials synthesized via solid-state methods is often hindered by the high costs associated with long reaction durations and elevated processing temperatures. In this study, we use the solid-state electrolyte Li₇La₃Zr₂O₁₂ (LLZO) as a model material to investigate the solid-state reaction pathway, identifying intermediates and exploring strategies to accelerate forward reactions while mitigating impurity formation. By manipulating reaction equilibria─specifically through the control of lithium precursor availability, we successfully suppress reverse reactions and achieve phase-pure LLZTO with electrochemical properties consistent with literature benchmarks, using a calcination time of only 30 min, representing a 10-fold reduction in reaction time. Operando and ex-situ characterization techniques were employed to probe the reaction dynamics at both surface and bulk levels, providing mechanistic insights. This work not only introduces a rapid approach to synthesizing LLZO, but also offers a generalizable framework that can be adapted for developing and optimizing other solid-state materials.

Hot electrons (HEs) can help realize chemical reactions that are unachievable by traditional methods, but HE-based chemistry is limited by the low yield and limited scalability of suitable hot-electron sources. We here demonstrate the potential of plasmonic homojunctions, interfaces between plasmonic structures with identical composition but varying electronic properties, to extract HEs with high efficiency and scalability. By engineering the emergence of morphological ordering in top-down fabricated gradient assemblies, a novel plasmonic interaction effect between neighboring particles was achieved. This plasmonic hybridization and the formation of a strong internal electric field facilitate efficient interfacial transfer of HEs. Characterization through ultrafast pump–probe and local photocurrent measurements reveals a 2-fold enhancement in hot electron lifetime and in external quantum efficiency. Our plasmonic homojunctions are applied to photocatalytic CO₂ conversion, outperforming previous approaches with an unprecedented CO product yield of 394.5 μmol g^–1 h^–1 and near-unity selectivity.

Multivariate metal–organic cages (MTV-MOCs) are multifunctional materials created by combining various organic ligands with different functional groups in a single structure. Under the guidance of reticular chemistry, we selected six ligands with identical main bodies but different functional groups [BDC-X, BDC = 1,4-benzenedicarboxylic acid, X = ethenyl (A), NH₂ (B), alkyne (C), Cl (D), F (E), and allyl (F)] and successfully constructed nine reticular MTV-MOCs. The optimized ZrT-1-AABBCD exhibited the best C₂H₂/CO₂ (50/50) separation performance. Both ideal adsorbed solution theory (IAST) selectivity (increased by 88.5%) and separation efficiency (increased by 375%) were significantly improved, compared to those of ZrT-1-ethenyl. Both experiments and theoretical simulations verified the synergistic mechanism of multifunctional groups and the excellent performance of this material system in C₂H₂/CO₂/CH₄ multicomponent gas separation. ZrT-1-AABBCD can also directly purify C₂H₂ in liquid solutions. This work provides theoretical guidance for the design of crystalline multivariate porous materials for gas separation.

The development of high-performance rubber materials has been a long-standing pursuit; currently, this has to go hand-in-hand with the design of polymers that are in some way recyclable. In this work, we report a class of thermosetting polyolefin elastomers synthesized via ring-opening metathesis polymerization of cycloheptene cross-linked with dicyclopentadiene. These cross-linked thermosets exhibit markedly enhanced chemical resistance, mechanical robustness, thermomechanical stability, and elasticity compared to those of their linear analogue. Notably, they demonstrate extraordinary extensibility, with strain at break exceeding 1700%, attributed to strain-induced crystallization confirmed by small- and wide-angle X-ray scattering analyses. Moreover, the elastomers are depolymerizable in the presence of Grubbs Catalyst second Generation, enabling recovery of cycloheptene in good yields of 77%–92%. Lastly, we show that the (thermo)mechanical properties of the materials could be further enhanced through the incorporation of activated charcoal, and the resulting composites still retain a certain level of depolymerizability, affording cycloheptene in a yield of 60%.

Na₃V₂(PO₄)₂F₃ (NVPF), featuring a sodium superionic conductor structure, is a promising cathode for sodium-ion batteries (SIBs), because of its robust framework and high operating potential. However, its application is limited by low electronic conductivity and moderate cyclability. Herein, we synthesized Fe²⁺-substituted NVPF (Na₃V_1.8Fe_0.2(PO₄)₂F₃, NVFPF) via a simple polyol reflux method to overcome these limitations. The Fe²⁺ substitution significantly enhanced the rate capability and structural stability. Consequently, NVFPF exhibited excellent rate performance (∼96 mAh g^–1 at 30 C) and outstanding cycling stability (81% retention after 1000 cycles at 5 C). Improved electronic conductivity was predicted by density functional theory calculations and verified experimentally by four-point probe measurements. Furthermore, in-situ X-ray diffraction and X-ray absorption near-edge structure analyses elucidated the underlying reaction mechanisms responsible for the enhanced sodium storage kinetics. This study addresses conductivity challenges in high-voltage SIB cathodes, presenting a viable pathway for the development of high-performance materials for practical energy storage applications.

Electrolyte-gated transistors with ion-trapping layers offer a promising platform for artificial synapses in neuromorphic computing, yet molecular mechanisms governing ionic retention remain poorly understood. Here, we present a supramolecular approach to modulate ion retention by incorporating a crown ether derivative-based polymer network as an ion-trapping layer on top of a semiconducting monolayer. We show that the balance between ion–host binding and ion–solvent interactions dictates the kinetics of ion capture and release, which in turn controls the memory characteristics of the device. By varying the solvent dielectric constant, we tune the ionic retention time from nearly permanent trapping to rapid relaxation. Intermediate solvent polarity enables programmable short- and long-term synaptic behaviors, including excitatory postsynaptic current, paired-pulse facilitation, and long-term potentiation and depression. These findings establish a direct link between supramolecular ion recognition and synaptic plasticity and provide a generalizable design strategy for ionic–electronic neuromorphic devices.