ACS Materials Letters最新文献

Separation of methanol-to-olefin products to obtain high-purity C₂H₄ and C₃H₆ has been deemed as one sustainable method for providing such indispensable industrial feedstocks. To meet the practical separation conditions, it is of critical significance to develop adsorbents that can separate C₃H₆/C₂H₄ under high-temperature and high-humidity conditions. Herein, we reported an anion-functionalized cage-like MOF (SIFSIX-Cu-TPA) showing a high-stability structure and huge distinction in C₃H₆ and C₂H₄ adsorption. Furthermore, C₃H₆- and C₂H₄-loaded single-crystal structures clearly reveal that more supramolecular interactions are generated between the C₃H₆ molecule and SIFSIX-Cu-TPA. Breakthrough experiments show that SIFSIX-Cu-TPA can efficiently separate C₃H₆/C₂H₄. After one separation cycle, 3.5 mol kg^–1 of high-purity C₂H₄ (>99.95%) and 2.5 mol kg^–1 of polymer-grade C₃H₆ (>99.5%) can be obtained from a C₃H₆/C₂H₄ (50/50) mixture at ₂98 K. More importantly, even at 338 K and 100% relative humidity, polymer-grade C₂H₄ (2.7 mol kg^–1) and C₃H₆ (1.4 mol kg^–1) can also be collected.

Solar-driven water management such as water purification via evaporation and condensation has gained increasing attention as a promising solution to address the current issues of water and energy scarcity. Herein, a nanocomposite hydrogel incorporating Ag nanoparticle (NP)-loaded boron nanosheets within a polyacrylamide matrix was fabricated, which exhibited excellent solar light absorption efficiency and photothermal conversion capability. Under simulated 1-sun irradiation, the membrane demonstrated an evaporation rate of 4.572 kg m^–2 h^–1 when used with simulated seawater (∼3.5 wt % NaCl), and the cation concentration in the desalinated water was reduced by 3–4 orders of magnitude. The membrane’s excellent performance is attributed to its gradient porous structure with different wettability between the upper and lower surfaces, the plasmonic effect of Ag NPs, and the high water affinity of the boron nanosheets. Additionally, the fabricated membrane showed an excellent pollutant degradation capability and demonstrated potential applications in temperature sensing and thermoelectric generation.

Fe-based two-dimensional (2D) materials have attracted considerable attention as an optimal platform for exploring magnetism, superconductivity, and phase transitions. In this study, we successfully fabricated Fe₃Se₄ nanoplates on WSe₂ nanosheets via a chemical vapor deposition approach. Optical microscopy images disclose that Fe₃Se₄ nanoplates either display single domains or achieve complete coverage on the WSe₂ nanosheets. Magneto-transport measurements exhibit a captivating crossover of magnetoresistance (MR) with feeble hysteresis around 120 K, where positive and negative MR values are respectively witnessed below and above this temperature. This phenomenon is ascribed to the alterations in the dominant spin characteristics. Another salient feature is the intersection of hysteresis branches observed in the anomalous Hall effect measurements. Moreover, both the magneto-transport and vibrating sample magnetometer outcomes suggest that Fe₃Se₄ nanoplates possess magnetic properties near room temperature. These findings imply that Fe₃Se₄ nanoplates are prospective candidates for the development of energy-efficient logic devices.

Noninvasive optical imaging techniques, including X-ray and near-infrared (NIR), hold significant value for scientific research and industrial applications. However, there is still a lack of a convenient platform that integrates X-ray imaging and NIR imaging in both bright- and dark-field applications. Here, a rare-earth ion-doped LaNbO₄:Pr,Er photochromic luminescent material is developed, integrating X-ray-induced coloration, NIR-induced bleaching, photoluminescence, and luminescence modulation. Under alternating X-ray and NIR light irradiation, the reflectivity and luminescence intensity can be reversibly tuned to display four optical states: white, black, dark, and bright. By utilizing the switchable optical states, quad-mode imaging of X-ray and NIR in bright and dark fields is achieved. NIR-induced photobleaching imaging, when employed as adjuncts to X-ray-induced photochromic imaging, has the potential to significantly reduce radiation-induced damage to biological tissues. These results provide unique insights for designing advanced materials and photonic storage technologies toward advanced multiwavelength, multienvironment, and multimode noninvasive imaging.

Benzothiadiazole offers an effective charge transfer channel and serves as a suitable unit for constructing donor–acceptor (D–A) covalent–organic frameworks (COFs), yet systematic investigation on benzothiadiazole-containing COFs is still rare. Herein, we construct four highly crystalline COFs and carefully explore their H₂O₂ photosynthetic efficiency. Changing the donor unit from phenyl to naphthalenyl group effectively enhances the H₂O₂ yield rate by nearly 3-fold, highlighting the importance of regulating D–A configuration. The optimized COF (BTpaNda) presents a high H₂O₂ yield rate of 10,122 μmol g^–1 h^–1. Theoretical calculations reveal that BTpaNda COF has the lowest Gibbs free energy in rate-determining oxygen-containing intermediate formation, corroborating the superb H₂O₂ photosynthesis. Furthermore, the BTpaNda COF demonstrates good stability and excellent bacterial elimination effects with the involvement of oxygen-containing intermediates. Thus, the structural regulation of benzothiadiazole-containing COFs on photocatalytic H₂O₂ generation and cascade bacterial elimination with oxygen-containing intermediate generation is demonstrated.

The practical application of electrocatalytic CO₂ reduction requires adaptation to the fluctuating voltage output of photovoltaic systems. However, potential-induced in-situ reconstruction of the catalyst complicates control and leads to Faradaic efficiency (FE) instability across the potential window. Here, we present a redox graphene-supported indium oxide catalyst (G-InO_x), where rGO effectively regulates the surface evolution of InO_x from In³⁺ to In⁰ during electrocatalytic reactions. The multivalent In generated via electrocatalytic in-situ reconstruction lowers the energy barriers for *OCHO formation and dissociation, enhancing formate production. rGO also regulates the surface environment, optimizing CO₂ and proton delivery to the active sites. Over a wide potential range (−0.86 to −1.37 V vs RHE), G-InO_x achieves FE_formate nearly 100%. This work offers a straightforward and efficient strategy for scalable, high-performance CO₂ electroreduction.

Plasmonic systems based on metallic nanostructures have special properties for light localization, photon transportation, and energy harvesting and have been widely applied in various optical applications. Here, we propose a tunable plasmonic system composed of disordered palladium (Pd) nanoparticles (NPs) on a planar optical cavity. We manipulate optical absorption intensity and bandwidth by controlling the effective thickness of the Pd NPs, which achieve an ultralow reflectance of 0.06%. Furthermore, the optical absorption mode of the plasmonic system can be modulated by the hydrogen absorption of the Pd NPs. The tunable optical absorption of the plasmonic system can be explained by the coupled-mode theory. This Pd-based plasmonic system will not only facilitate a further understanding of the optical properties of disordered systems but also provide a novel platform for practical applications such as visual hydrogen sensing.

Weak yet ubiquitous van der Waals (vdW) interactions play an essential role in shaping the structure, stability, and functionality of materials. Particularly, intermolecular vdW interactions profoundly impact molecular stacking orders and electronic properties. However, comprehending and precisely controlling intermolecular vdW interactions has posed a longstanding challenge. Here, we employ a combination of single-molecule electrical measurements and theoretical calculations to dissect and further regulate sophisticated vdW interactions in a single-dimer junction. Specifically, by introducing an aminomethyl group, the electrostatic force resulting from the dipole–dipole interaction predominantly dictates the bistable conformation and conductance of benzylamine dimers. As molecular π-conjugation increases, the influence of exchange and dispersion interactions is significantly amplified in (9H-fluoren-2-yl)methylamine dimers. Furthermore, the application of electric fields effectively modulates the vdW interactions in dimers, impacting their structures and conductance. Investigating these vdW interactions yields profound insights into the fundamental principles governing the behavior of chemical and biological systems.

To achieve stable organic light emitting diodes (OLEDs), great efforts are devoted to accelerating the reverse intersystem crossing (RISC) process of efficient thermally activated delayed fluorescence (TADF). Here, we focus on spin–orbit coupling engineering to increase the rate constant of RISC and the photoluminescence quantum yield (PLQY). Three TADF emitters consisting of a carbonly carbazole core as the initially donor–acceptor system plus diphenylamine as the π-extended group were developed. We show that this design strategy realizes the fine adjustment of excited states to effect the spin–orbit coupling (SOC) matrix element between triplet and singlet states, resulting in accelerating k_RISC while maintaining high PLQYs and small ΔE_ST. OLEDs achieved excellent electroluminescence performance with a maximum external quantum efficiency of 23.8% and low efficiency roll-off, demonstrating great potential in efficient OLEDs.