材料科学最新文献

Triboelectricity

PDMS-based triboelectric nanogenerator (TENG) under nanoscale investigation, employing a scanning near-field optical microscope. A conductive probe mounted at the end of the cantilever generates nanofocus for incident infrared irradiation, scattered light reveals the surface chemical properties of the pristine versus aged PDMS films. Breakage of SiO bonds results in the chain scission process that will degrade TENG performance. More details can be found in article 2400094 by Jin-Chong Tan and co-workers.

Hydrogen peroxide (H₂O₂) plays a pivotal role in advancing sustainable technologies due to its eco-friendly oxidizing capability. The electrochemical two-electron (2e^-) oxygen reduction reaction and water oxidation reaction present an environmentally green method for H₂O₂ production. Over the past three years, significant progress is made in the field of carbon-based metal-free electrochemical catalysts (C-MFECs) for low-cost and efficient production of H₂O₂ (H₂O₂EP). This article offers a focused and comprehensive review of designing C-MFECs for H₂O₂EP, exploring the construction of dual-doping configurations, heteroatom-defect coupling sites, and strategic dopant positioning to enhance H₂O₂EP efficiency; innovative structural tuning that improves interfacial reactant concentration and promote the timely release of H₂O₂; modulation of electrolyte and electrode interfaces to support the 2e^- pathways; and the application of C-MFECs in reactors and integrated energy systems. Finally, the current challenges and future directions in this burgeoning field are discussed.

Integration of inherently incompatible elements into a single sublattice, resulting in the formation of monophasic metal oxide, holds great scientific promise; it unveils that the overlooked surface entropy in subnanometer materials can thermodynamically facilitate the formation of homogeneous single-phase structures. Here a facile approach is proposed for synthesizing multimetallic oxide subnanometer nanobelts (MMO-PMA SNBs) by harnessing the potential of phosphomolybdic acid (PMA) clusters to capture inorganic nuclei and inhibiting their subsequent growth in solvothermal reactions. Experimental and theoretical analyses show that PMA in MMO-PMA SNBs not only aids subnanometer structure formation but also induces in situ modifications to catalytic sites. The electron transfer from PMA, coupled with the loss of elemental identity of transition metals, leads to electron delocalization, jointly activating the reaction sites. The unique structure makes pentametallic oxide (PMO-PMA SNBs) achieve a current density of 10 mA cm^-2 at a low potential of 1.34 V and remain stable for 24 h at 10 mA cm^-2 on urea oxidation reaction (UOR). The exceptional UOR catalytic activity suggests a potential for utilizing multimetallic subnanometer nanostructures in energy conversion and environmental remediation.

By using low-temperature scanning tunneling microscopy and spectroscopy (STM/STS), we observe in-gap states induced by Andreev tunneling through a single impurity state in a low carrier density superconductor (NaAlSi). The energy-symmetric in-gap states appear when the impurity state is located within the superconducting gap. In-gap states can cross the Fermi level, and they show X-shaped spatial variation. We interpret the in-gap states as a consequence of the Andreev tunneling through the impurity state, which involves the formation or breakup of a Cooper pair. Due to the low carrier density in NaAlSi, the in-gap state is tunable by controlling the STM tip-sample distance. Under strong external magnetic fields, the impurity state shows Zeeman splitting when it is located near the Fermi level. Our findings not only demonstrate the Andreev tunneling involving single electronic state but also provide new insights for understanding the spatially dependent in-gap states in low carrier density superconductors.

The robust characterization of lipid nanoparticles (LNPs) encapsulating therapeutics or vaccines is an important and multifaceted translational problem. Sedimentation velocity analytical ultracentrifugation (SV-AUC) has proven to be a powerful approach in the characterization of size-distribution, interactions, and composition of various types of nanoparticles across a large size range, including metal nanoparticles (NPs), polymeric NPs, and also nucleic acid loaded viral capsids. Similar potential of SV-AUC can be expected for the characterization of LNPs, but is hindered by the flotation of LNPs being incompatible with common sedimentation analysis models. To address this gap, we developed a high-resolution, diffusion-deconvoluted sedimentation/flotation distribution analysis approach analogous to the most widely used sedimentation analysis model c(s). The approach takes advantage of independent measurements of the average particle size or diffusion coefficient, which can be conveniently determined, for example, by dynamic light scattering (DLS). We demonstrate the application to an experimental model of extruded liposomes as well as a commercial LNP product and discuss experimental potential and limitations of SV-AUC. The method is implemented analogously to the sedimentation models in the free, widely used SEDFIT software.

Green hydrogen from electrolysis of water has attracted widespread attention as a renewable power source. Among several hydrogen production methods, it has become the most promising technology. However, there is no large-scale renewable hydrogen production system currently that can compete with conventional fossil fuel hydrogen production. Renewable energy electrocatalytic water splitting is an ideal production technology with environmental cleanliness protection and good hydrogen purity, which meet the requirements of future development. This review summarizes and introduces the current status of hydrogen production by water splitting from three aspects: electricity, catalyst and electrolyte. In particular, the present situation and the latest progress of the key sources of power, catalytic materials and electrolyzers for electrocatalytic water splitting are introduced. Finally, the problems of hydrogen generation from electrolytic water splitting and directions of next-generation green hydrogen in the future are discussed and outlooked. It is expected that this review will have an important impact on the field of hydrogen production from water.

Manipulating the crystallographic orientation of zinc (Zn) metal to expose more (002) planes is promising to stabilize Zn anodes in aqueous electrolytes. However, there remain challenges involving the non-epitaxial electrodeposition of highly (002) textured Zn metal and the maintenance of (002) texture under deep cycling conditions. Herein, a novel organic imidazolium cations-assisted non-epitaxial electrodeposition strategy to texture electrodeposited Zn metals is developed. Taking the 1-butyl-3-methylimidazolium cation (Bmim⁺) as a paradigm additive, the as-prepared Zn film ((002)-Zn) manifests a compact structure and a highly (002) texture without containing (100) signal. Mechanistic studies reveal that Bmim⁺ featuring oriented adsorption on the Zn-(002) plane can reduce the growth rate of (002) plane to render the final exposure of (002) texture, and homogenize Zn nucleation and suppress H₂ evolution to enable the compact electrodeposition. In addition, the formulated Bmim⁺-containing ZnSO₄ electrolyte effectively sustains the (002) texture even under deep cycling conditions. Consequently, the combination of (002) texture and Bmim⁺-containing electrolyte endows the (002)-Zn electrode with superior cycling stability over 350 h under 20 mAh cm^-2 with 72.6% depth-of-discharge, and assures the stable operation of full Zn batteries with both coin-type and pouch-type configurations, significantly outperforming the (002)-Zn and commercial Zn-based batteries in Bmim⁺-free electrolytes.

Despite the advantages of high tissue penetration depth, selectivity, and non-invasiveness of photothermal therapy for cancer treatment, developing NIR-II photothermal agents with desirable photothermal performance and advanced theranostics ability remains a key challenge. Herein, a universal surface modification strategy is proposed to effectively improve the photothermal performance of vanadium carbide MXene nanosheets (L-V₂C) with the removal of surface impurity ions and generation of mesopores. Subsequently, MnO_x coating capable of T1-weighted magnetic resonance imaging can be in situ formed through surface redox reaction on L-V₂C, and then, stable nanoplatforms (LVM-PEG) under physiological conditions can be obtained after further PEGylation. In the tumor microenvironment irradiated by NIR-II laser, multivalent Mn ions released from LVM-PEG, as a reversible electronic station, can consume the overexpression of glutathione and catalyze a Fenton-like reaction to produce ·OH, resulting in synchronous cellular oxidative damage. Efficient synergistic therapy promotes immunogenic cell death, improving tumor-related immune microenvironment and immunomodulation, and thus, LVM-PEG can demonstrate high accuracy and excellent anticancer efficiency guided by multimodal imaging. As a result, this study provides a new approach for the customization of 2D surface strategies and the study of synergistic therapy mechanisms, highlighting the application of MXene-based materials in the biomedical field.

Drug-resistant bacterial infections and their lipopolysaccharide-related inflammatory complications continue to pose significant challenges in traditional treatments. Inspired by the rapid initiation of resident macrophages to form aggregates for efficient antibacterial action, this study proposes a multifunctional and enhanced antibacterial strategy through the construction of novel biomimetic cell membrane polypeptide nanonets (R-DPB-TA-Ce). The design involves the fusion of end-terminal lipidated polypeptides containing side-chain cationic boronic acid groups (DNPLBA) with cell membrane intercalation engineering (R-DPB), followed by coordination with the tannic acid-cerium complex (TA-Ce) to assemble into a biomimetic nanonet through boronic acid-polyphenol-metal ion interactions. In addition to the ability of RAW 264.7 macrophages cell membrane components' (R) ability to neutralize lipopolysaccharide (LPS), R-DPB-TA-Ce demonstrated enhanced capture of bacteria and its LPS, leveraging nanoconfinement-enhanced multiple interactions based on the boronic acid-polyphenol nanonets skeleton combined with polysaccharide. Utilizing these advantages, indocyanine green (ICG) is further employed as a model drug for delivery, showcasing the exceptional treatment effect of R-DPB-TA-Ce as a new biomimetic assembled drug delivery system in antibacterial, anti-inflammatory, and wound healing promotion. Thus, this strategy of mimicking macrophage aggregates is anticipated to be further applicable to various types of cell membrane engineering for enhanced antibacterial treatment.

The interplay between Cooper pairs and Bogoliubov-de Gennes (BdG) quasiparticles is a topic of considerable interest in the quantum properties of solids, but its important ingredient, the sufficient amount of low-energy quasiparticles to interact with Cooper pairs remains elusive in conventional superconductors. Here a gapless superconductor with coupled paramagnetic atomic layers is used to generate a significant amount of zero-energy quasiparticles that Anderson-localize and bifurcate into regions of high and low zero-energy quasiparticle density of states. The enriched zero-energy quasiparticles induce puddled superconductivity and Josephson vortices. This discovery not only advances the understanding of the mutual interaction of Cooper pairs and BdG quasiparticles but also opens a new avenue for exploring and controlling exotic quantum phenomena where superconductivity, disorder, and spin degrees of freedom are entangled.