Chemistry of Materials最新文献

Solution combustion synthesis (SCS) is a low-temperaturesynthesistechnique leveraging a highly exothermic combustion reaction betweena metal complexed by an organic fuel and oxidant (e.g., nitrate) togenerate metals and metal compounds such as oxides, nitrides, andcarbides at reduced applied temperatures compared to conventionalsolution methods. However, many ideal hydrocarbon fuels for low-temperaturecombustion processes are too volatile and noncoordinating to metalcations in solution, making them poorly suited for SCS. Here, we presentSCS complexing agents, which contain t-butyl esterfunctionality capable of generating isobutylene in situ at low appliedtemperatures, which acts as a potent fuel in the combustion process.We form four important oxides and metal/oxide combined nanostructures:InO_x, MnO_x, NiO_x, and CoO_x at applied temperatures <150 °C including the formationof InOx at <80 °C which is, to our knowledge, the lowest purelyheat-initiated SCS reaction observed to date. This work reveals thatisobutylene-generating fuels, particularly for the indium cation,are a powerful tool for applications demanding oxides at low formationtemperatures.

Covalent organic frameworks (COFs) have emerged as promisingmetal-freephotocatalysts; however, their widespread application is often hinderedby the time-consuming solvothermal preparation. Developing rapid andcost-effective routes to highly crystalline COFs is therefore essentialfor expanding their practical utility. In this regard, microwave-assistedsynthesis offers a distinct advantage over conventional solvothermalmethods by shortening reaction times from days to minutes while simultaneouslyimproving crystallinity. Here, we report a microwave-assisted strategyfor synthesizing enaminone-COFs via the Michael addition-eliminationreaction, achieving >90% yields within 60 min. The developed microwave-assistedstrategy demonstrated broad versatility by enabling the synthesisof six distinct enaminone COFs. Notably, the microwave-synthesizedCOFs exhibited physical properties similar to previously reportedframeworks. Among the synthesized enaminone COFs, COF-Tz-MW and COF-Bz-MWwere rationally engineered with tunable nitrogen content, creatingdistinct local microenvironments that modulate the acceptor–donor–acceptor(A–D–A) charge-transfer pathway for efficient photocatalyticH₂O₂ synthesis. This molecular-level variationwas systematically investigated to elucidate its influence on chargedistribution and photophysical properties, revealing a clear structure–reactivitycorrelation of enaminone-COFs in H₂O₂ photosynthesis.Notably, the COF-Bz-MW demonstrated effective charge separation andsuperior H₂O₂ production performance with aproduction rate of 8.70 mmol g^–1 h^–1 from blue LED-H₂O–O₂. Theoretical studiesrevealed that the enaminone moiety coupled with the benzene core aminecreates an optimized A–D–A configuration, enhancingO₂-adsorption and promoting efficient photocatalytic H₂O₂ production. Our work pioneers a paradigm forfacile and rapid synthesis of enaminone COFs, while demonstratingN-site microenvironment engineering as an effective strategy to advanceCOF-based photocatalysts for efficient photocatalytic H₂O₂ production.

Alkali metal electrodesare considered promising enablersof next-generationhigh energy density batteries and are commonly utilized in half cellsfor electrochemical characterization of battery materials. Their highreactivity with common battery electrolytes and nonplanar electrodepositionunder constant current drives complex interphase formation and morphologicalinstability, challenging a stable and reliable application. This reviewhighlights how electrochemical methods─specifically electrochemicalimpedance spectroscopy (EIS) and galvanostatic polarization in symmetriccells─provide powerful, in situ, and nondestructive tools tostudy material properties and the kinetics of their degradation incells. We summarize recent key findings and demonstrate how time,temperature, and current-dependent electrochemical responses yieldvaluable insights into the electrochemical and morphological stabilityand kinetics of both naturally formed and artificial alkali metalinterphases. We further show how both methods are effectively usedto understand the charge-transfer process and diffusion under anion-blockingconditions and determine effective cationic transference numbers ofa variety of contemporary battery electrolytes, essential for theirstructure–property evaluation.

Reversible and wavelength-selective luminescence modulationisessential for advanced optical encryption, anticounterfeiting, andadaptive photonic devices. However, conventional photochromism-inducedluminescence regulation is usually governed by a reabsorption effect,leading to nonselective intensity modulation. Herein, PbWO₄:Yb³⁺/Er³⁺ inverse opal photonic crystals werefabricated through a template-assisted stepwise infiltration strategy,in which W- and Pb-containing precursor sols were sequentially introducedto avoid precipitation and ensure the formation of ordered photonicarchitectures. The obtained PbWO₄:Yb³⁺/Er³⁺ inverse opals exhibit tunable photonic stop-bands and distinctstructural colors. By matching the photonic bandgap with Er³⁺ emission bands, wavelength-selective inhibition and band-edge-enhancedupconversion luminescence were achieved, enabling the regulation ofthe red-to-green emission ratio. X-ray-induced photochromism originatesfrom the synergistic effect of oxygen vacancy-related color centerformation and polaron hopping associated with W⁶⁺/W⁵⁺ mixed-valence states, providing a reversible route for overallemission intensity modulation. Benefiting from the structural-colormasking effect and coloration-induced upconversion luminescence modulation,concealed information writing and 980 nm laser-readable optical patternswere demonstrated. This work provides an effective strategy for integratingphotonic bandgap engineering with photochromism toward upconversionluminescence modulation and advanced optical anticounterfeiting applications.

Hexagonal boron nitride(hBN) is a van der Waals materialwithexcellent insulating properties that make it well-suited as a gatedielectric in 2D electronic devices. In recent years, the discoveryof an ever-increasing list of properties has led to a much broaderrange of potential applications, including quantum photonics, memristivedevices, and extreme-environment coatings. However, current growthmethods for hBN films are characterized by a narrow selection of substratesand high temperatures that require transfer and limit scale-up. Here,we report a remote plasma-activated approach to directly synthesizelarge-area hBN films on a diverse range of representative metallic,semiconducting, and amorphous insulating substrates. Specifically,we employ the spatial afterglow of an Ar/H₂ plasma to activateammonia borane, which enables the growth of thick (>30 nm), uniform,and stoichiometric films on substrates such as Si, SiO₂, glass, fused silica, Mo, and Al. Systematic spectroscopic characterizationreveals that hBN films can be grown as low as 300 °C. Furthermore,plasma afterglow-grown hBN films exhibit mechanical, electrical, andthermal properties on par with or exceeding those reported by alternatesynthesis methods. These results establish plasma afterglow growthfor the direct integration of hBN into a wide range of emerging technologies.

Atomistic simulations can provide critical insights intothe fundamentalbehavior of battery materials. A necessary input for such simulationsis a description of the potential energy surface (PES). Over the pastdecade, machine learning interatomic potentials (MLIPs) have emergedas a powerful approach to model the PES at near-first-principles accuracywith orders of magnitude lower computational cost. In this perspective,we examine the role of atomistic simulation in battery research, especiallyin the context of the capabilities afforded by MLIPs. We outline theiradvantages and trade-offs relative to ab initio methods and discuss how they enable the prediction of key intrinsicproperties relevant to battery materials, especially for solid statebatteries. We further explore their potential for modeling interfacesand chemical reactivity, as well as their integration into high-throughputscreening and materials discovery workflows. Finally, we highlightpromising applications and identify requirements for the next generationof MLIPs to advance the study of battery materials.

Self-healing and shape memory hydrogels have emergedas a transformativeclass of materials poised to reform next-generation bioelectronics,soft robotics, and actuation systems. By combining biocompatibility,mechanical tunability, and autonomous repair properties, these materialsoffer unique advantages for designing resilient and multifunctionaldevices that mimic the adaptability and responsiveness of biologicaltissues. This review provides a comprehensive analysis of the recentprogress in the molecular design, network architectures, fabricationstrategies, and functional integration of self-healing hydrogels intosmart devices. Emphasis is placed on understanding the dynamic bondingmechanisms involving reversible covalent and supra-molecular interactionsthat impart self-repair capabilities while balancing mechanical robustness,conductivity, and biocompatibility. Special attention is given tohighlighting how self-healing and shape memory functionalities enhancedevice durability, responsiveness, and long-term performance. We furtherexplore the role of stimuli-responsive mechanisms, such as pH, temperature,and electrical signals, in enabling adaptive actuation and signaltransduction. Additionally, the key challenges such as healing speed,operational stability in physiological environments, and seamlessmultifunctionality have been discussed and outline future directionstoward programmable, autonomous, and multifunctional hydrogel systems.