Highly selective thin-film composite membranes for hot hydrogen sieving are prepared via the pyrolysis of thin cyclomatric polyphenoxy phosphazene films that are prepared via non-conventional interfacial polymerization of hexachlorocyclotriphosphazene with 1,3,5-trihydroxybenzene or m-dihydroxybenzene. The presence of the cyclic phosphazene ring within the weakly branched polymer films gives rise to a distinct thermal degradation evolution, with an onset temperature around 200 °C. For the trihydroxybenzene derived material, the hydrogen permselectivity of the films shows a maximum around a pyrolysis temperature of 450 °C. At this temperature a compact atomic structure is obtained that comprises mostly disordered carbon and accommodates P-O-C and P-O-P bonds. During thermal treatment, these films reveal molecular sieving with permselectivities exceeding 100 for H2/N2, H2/CH4, and H2/CO2, and a hydrogen permeance of 2×10–10 to 1.5×10–-8 mol m–2s–1Pa–1 (0.6-44.8GPU), at 200 °C. At ambient temperatures, thin films are very effective barriers for small gas molecules. Because of the inexpensive facile synthesis and low temperature pyrolysis, the polyphosphazene films have the potential for use in high-temperature industrial gas separations, as well as for use as barriers such as liners in high pressure hydrogen storage vessels at ambient temperature.

The development of low-cost, stable, and highly-active bifunctional catalysts is an important step to realize high-performance rechargeable Zn-air batteries. Herein, we report an innovative air cathode of three-dimensionally (3D) ordered macroporous Co3O4@WO3 composite arrays on a flexible carbon cloth substrate prepared by the decoration of Co3O4 nanosheets on electrodeposited macroporous WO3 inverse opals. Benefiting from a high specific surface area, rich active sites, and a facilitated charge/mass transfer process provided by the 3D ordered macroporous structure, the as-prepared Co3O4@WO3 composite exhibits excellent bifunctional catalytic activity with a half-wave potential of 0.75 V for oxygen reduction reaction and an overpotential of 339 mV at 10 mA/cm2 for oxygen evolution reaction, contributing to a low oxygen potential gap (ΔE) of 0.81 V. Furthermore, Co3O4@WO3 composite arrays are directly used as a binder-free air cathode for rechargeable Zn-air batteries, ensuring excellent mechanical and electrochemical stability. The aqueous Zn-air batteries based on 3D Co3O4@WO3 air cathodes exhibit excellent performance, in terms of a high specific capacity of 828.6 mAh/gZn1 at 5 mA/cm2 and long-term cycling stability of over 646 h.

In this work, the Ti3C2 MXene was modified with Fe3O4 nanoparticles to obtain a composite with in-plane optical anisotropy and surface plasmon properties. Based on a side-polished D-shaped fiber (DSF), this Fe3O4/Ti3C2 MXene (F/M) composite exhibits a tunable nonlinear optical (NLO) absorption response under 1.5 μm laser excitation with different polarization states. The modulation depths can be obtained from 0.9% to 12.1%. As an application, the ultrafast erbium-doped fiber laser (EDFL) with multiple pulsed laser operations was demonstrated using the F/M-DSF device as a saturable absorber (SA). Both stable Q-switching and mode-locking operations were demonstrated in the same all-fiber laser cavity, which generated pulsed laser with microsecond and sub-picosecond durations respectively. In addition, the bound state (BS) of solitons in harmonic mode-locked lasers with the pulse time interval of 3 ps and the highest order of 30th was also realized. This versatile and simple-structured all-fiber laser has great potential in various applications, such as optical communication. With the numerical simulations, the dynamic of F/M composite-based soliton mode-locking was also explored, illustrating the mechanism of soliton formation and propagation. This work not only expands the advanced applications of F/M composite in ultrafast photonics but also provides a new perspective for designing and optimizing its ultrafast modulating performance.

To reduce the cost of the electrocatalyst for the oxygen reduction reaction in proton exchange membrane fuel cells, supported metal alloy nanoparticles are commonly used to decrease the amount of the scarce and expensive Pt. Since the structure of the nanoparticles has a crucial influence on the catalytic properties, advanced characterization methods help elucidate these relationships and ultimately enable more rational synthesis. This work focuses on investigating the presence of one particular planar defect, namely periodic anti-phase boundaries in carbon-supported PtCu3 nanoparticles. The studying of this structural phenomenon was approached with several characterization tools. Ex-situ X-ray diffractograms were used in conjunction with computer simulations and Rietveld analyses to reliably determine the modulated unit cell containing anti-phase boundaries, while their temperature-dependent formation and disappearance were observed with high-temperature X-ray powder diffraction. In addition, their presence was also confirmed by electron diffraction and atomically resolved scanning transmission electron microscopy. Furthermore, the average neighborhood of Cu and Pt atoms was confirmed using extended X-ray absorption fine structure. Finally, the electrocatalytic activity for the oxygen reduction reaction for composites with and without anti-phase boundaries was determined using a thin-film rotating disk electrode, and the performance was found to correlate with the degree of alloy ordering but not with the presence of anti-phase boundaries. Overall, this study represents a significant step towards better control over the atomically precise synthesis of advanced functional metallic materials by providing valuable insight into the formation of planar defects in metallic alloy nanoparticles and their impact on the structure-property relationships of electrocatalysts.

Developing efficient and highly selective photocatalytic CO2 reduction catalysts remains one of the most significant challenges in achieving carbon neutrality. Herein, the efficient conversion of CO2 to CH4 with selectivity close to 100% was achieved by loading uniformly dispersed Pt nanoparticles on the surface of Sr2Nb2O7 nanosheets; the optimal CH4 yield was as high as 15.65 μmol/g/h. Various characterizations demonstrate that Pt nanoparticles have a significant photothermal effect that can increase the catalyst surface temperature, and improve the performance and electron transport rate of the catalyst. Additionally, Pt nanoparticles and Sr2Nb2O7 nanosheets form heterojunctions, which facilitate the separation of photogenerated carriers and aggregation of photogenerated electrons on the Pt nanoparticles. Pt nanoparticles become new reactive sites that have a strong adsorption impact on the key intermediate ∗CO and reduce the reaction energy barrier of ∗CHO generation. The results revealed that the synergy between electron accumulation, strong adsorption of ∗CO, and reduction of the reaction potential of ∗CHO are the reasons for the efficient and selective conversion of CO2 to CH4. This work provides novel insights into the role of metal-based cocatalysts in selective CO2 photoconversion and new ideas for designing efficient CO2 conversion systems.

MoSe2 has attracted widespread attention owing to its ability to promote photocatalytic hydrogen evolution reaction (HER), but progress has been hindered by the lack of active site in the planar and the unsuitable Heyrovsky reaction. Here, onion-like MoSe2 with biaxially strained nanostructure (MoSe2-L) was synthesized by laser ablation in liquids. The photocatalytic HER rate was extensively promoted by MoSe2-L in the heterojunction of MoSe2-L/CN. The strain makes the negatively charged state of MoSe2-L. The negatively charged state would produce the adsorbed hydrogen atom negatively charged for the Heyrovsky reaction, which is conducive to the further adsorption of the next proton for H2 formation. Meanwhile, the strain can significantly enhance the charge transfer in the heterojunction, increasing photocatalytic H2 production. This study provided new insight into structural strain engineering in the photocatalytic HER field.

Targeted brain tumor therapy by nanoparticles (NPs) remains a daunting challenge due to the difficulty for NPs to go through the blood-brain barriers (BBB) and blood-brain tumor barriers (BBTB). In addition, Dactolisib (Dac) is an effective dual PI3K/mTOR inhibitor for cancer treatment. It was the first PI3K inhibitor to enter clinical trials but exhibited toxicity to normal tissues if not delivered to tumor sites by a tumor-targeting carrier. To explore Dac for glioblastoma (GBM) therapy while avoiding its toxicity, we developed a new brain tumor-targeting drug delivery system self-assembled from zein, a cell membrane-penetrating amphiphilic protein originally present in corn. Specifically, the amphiphilicity of zein drove it to self-assemble into NPs that encapsulated Dac with high efficiency. RVG29, a 29-mer brain-targeting peptide, was chemically conjugated to zein constituting the NPs, forming Dac-encapsulated NPs (zein-RVG-Dac_NPs). In vitro assays were conducted to verify the capability of the NPs in penetrating BBB/BBTB, targeting GBM cancer cells and killing them. ELISA was employed to assess the expression of nicotinic acetylcholine receptors (nAChR) on the cancer cells to understand the mechanism of cancer cell membrane penetration by the NPs. The NPs were intravenously injected into orthotopic GBM mice models to demonstrate the brain tumor targeting as well as the effective GBM therapy due to the targeted delivery of Dac to brain tumors. The treated tumors were immunohistochemically analyzed to verify the tumor destruction. To confirm the biosafety of the NPs in treating GBM, we also histopathologically evaluated the major normal organs and chemically analyzed the blood biomarkers. We found that a combination of zein and RVG29 facilitated the zein-RVG-Dac_NPs to cross the BBB/BBTB and became uptaken by the GBM cells through the nAChR-mediated pathways, enabling the NPs to cross BBB/BBTB and deliver Dac selectively to GBM cells. Hence, administration of the NPs through tail veins significantly increased the accumulation of Dac in the orthotopic brain tumor of mice and effectively inhibited tumor growth. Neither toxicity nor adverse effects in the major organs were found due to the excellent biocompatibility of zein and the targeted delivery of Dac into brain tumor cells. Hence, integrating a cell-penetrating natural protein (zein) and a brain-targeting peptide (RVG29) can form NPs that can effectively penetrate BBB/BBTB and then enter brain tumor cells to release Dac, leading to highly effective targeted brain cancer therapy. Such NPs can be extended to the development of therapeutics for treating different brain diseases due to their unique combination of biocompatibility and brain-targeting capability.

Coupling electrocatalytic 5-hydroxymethylfurfural (HMF) oxidation reaction (HMFOR) with hydrogen evolution reaction (HER) is capable of potentially enhancing energy efficiency for hydrogen production and converting biomass into high-valued products. Herein, a novel metallic heterostructure based on Ni3S2 and Co9S8 (Co9S8@Ni3S2/NF) was designed for H2 production and selective oxidation of HMF into 2, 5-furandicarboxylic acid (FDCA). Benefiting from the merit of metal heterojunction, Co9S8@Ni3S2/NF not only possesses appropriate H∗ adsorption energy, but also promotes the adsorption and desorption process of organic, thus making reaction dynamics for both HER and HMFOR more exceptional. Furthermore, the anion exchange membrane (AEM) electrolyzer with Co9S8@Ni3S2/NF as anode and cathode electrodes toward HMFOR and HER only required a low potential of 1.61 V for continuous hydrogen and FDCA production at the initial current density of 50 mA/cm2. The generation rate of H2 and FDCA are as high as 45.6 L/h/m2 and 7.25 mg/h/cm2, corresponding to the Faraday efficiency of ∼100% and 93.0%, respectively. The in-situ Raman and theoretical calculations demonstrated that the electron transfer from Ni3S2 to Co9S8 at heterogeneous interface contributes to the formation of Ni/Co–OOH, which is the active species of HMFOR.

Tunable plasmonic gap nanostructures on flexible substrates have been considered as an evolutionary development in diverse fields. The size-controllable nano-gaps can process optical signals on the deep nanoscale to provide optimal and strong signal generation in a spatially controlled manner and flexible devices can realize rapid analysis, easy operation and cost-effectiveness. In addition, the creation of a number of exposed and vacant nano-gaps on flexible materials is essential for target molecules to diffuse into the nano-gaps. However, it remains challenging to synthesize a structure that satisfies these requirements. Herein, we present size-controllable, unoccupied, and exteriorly exposed nano-gaps on a flexible plasmonic sensor; control of the signal amplification ability is realized by changing the nano-gap distance. We prepared a graphene modified polyimide film and silver dendrites structures were electro-deposited. Then, secondary protruding gold nano-islands were deposited on silver dendrites via galvanic replacement. Controlling the morphology of gold nano-islands with different sizes and densities yielded different nano-gap lengths of 3–30 nm between the gold nano-islands in a controlled manner. It was achieved by manipulating the amount of injected gold precursor, reaction time, and solvent volume. Therefore, it was possible to control the degree of Raman signal enhancement with respect to the diminished nano-gap length. Benefiting from direct contact with the target area and the free diffusion of surrounding molecules to the void nano-gaps, this flexible plasmonic sensor was successfully used as a potent surface-enhanced Raman scattering sensor for monitoring the trace-amounts of a drug molecule on an arbitrary curved surface.

Wound healing as a fundamental health problem involves complex and dynamic biological processes. Multifunctional dressings that meet the needs of different wound stages can exert synergistic effects throughout the whole-process healing. In this work, inspired by the behavior of spider hunting, reduced polydopamine nanoparticles (rPDA) doped copper-based metal-organic frameworks (Cu-MOF)-hydrogel (GEL-MOF-rPDA) was prepared with anti-infection and promotion of whole-process wound healing. Schiff base cross-linking of dodecyl chitosan -oxidized sodium alginate was used as a biocompatible hydrogel substrate for hemostasis during wound healing and for steric fixation of bacteria during synergistic antibacterial processes. The dodecyl tail can be inserted and fixed on the lipid bilayer of the cell membrane while achieving bacterial capture, blood cell fixation, and skin cell fixation. Cu-MOF and rPDAs played in the hydrogel destroyed the outer membrane of bacteria and release 1O2 and Cu2+. The composite hydrogel had shown an excellent synergistic antibacterial effect with a 99.9% antibacterial rate. Furthermore, the mechanism of promoting whole-process wound healing was analyzed using an infected rat full-thickness skin defect model. The wound closure rate of the composite hydrogel treated wound was found as 92% at ten days. The bio-inspired synergistic antibacterial hydrogel solves the limitation of single-functional hydrogel in promoting whole-process wound healing through initial hemostasis, mid-term anti-infection and anti-inflammatory, late-stage anti-oxidation and promoting angiogenesis and granulation tissue formation. This biomimetic hydrogel paves the way for the design of multifunctional hydrogels and has good potential value in clinical applications.

The mechanism of frictional energy dissipation suggests that layered double hydroxides (LDHs) could be ideal materials for achieving solid state superlubricity due to their strong adsorption effect and weak internal interactions. In this work, three metal ion-coordinated LDHs nanosheets were designed to investigate the specific effect of surface microstructure on frictional properties. The experimental results showed that the lubrication performance is determined by the surface structure, and the friction coefficient doubles (2 × 10−3 to 3.9 × 10−3) and the adhesion force increases by 62.3% (6.9–11.2 nN) when the divalent metal ions change from tetrahedral to octahedral coordination. Through crystal field stability energy analysis and density functional theory (DFT) calculations, the superlubricity of LDHs materials is attributed to two aspects: firstly, the existence of strong charge density transfer between LDHs nanosheets and the probe, known as the anchoring effect; secondly, the formation of an ultra-low sliding energy barrier interface between LDHs nanosheets and highly oriented pyrolytic graphite (HOPG). Therefore, the relationship between tribological properties and surface structure can guide future research on superlubricity materials.

Natural wood is a widely used structural building material because of its light weight and high strength, yet it is limited by the ignitability. Traditional top-down strategies can delay the burning time of wood-derived materials but hardly reach incombustible performance. Here, we develop a bottom-up external force-induced assembly strategy to fabricate nonburning nacre-mimetic structural materials based on the shear-thinning behavior of cellulose nanofibers, the main component of wood. The highly ordered brick-and-mortar structure endows the structural material with excellent comprehensive mechanical properties and oxygen insulation, giving it better specific flexural strength [143 MPa/(Mg m−3)] and limit oxygen index (100%) than various natural woods. Furthermore, the house model, made of bioinspired structural materials, does not burn or collapse even in a butane blowtorch flame (more than 1100 °C), demonstrating its great potential as a sustainable, lightweight, strong, and safe structural building material.

Monolayer MoS2 is expected to become a mainstream 2D-semiconductor for next-generation optoelectronic sensing due to its fascinating physical properties. However, the low quantum efficiency, weak light absorption, and low photoluminescence (PL) of monolayer MoS2 result in the urgent need to introduce effective routes for manipulating light-matter interaction. All-dielectric nanostructures offer a promising platform for regulating light to complement or even replace conventional plasmonic structures by avoiding substantial heat dissipation. Here, we demonstrate that the PL enhancement of MoS2 is enhanced by up to 88 times, which is the best among the reported PL enhancements of all-dielectric nanostructures, and exceeds most of the enhancements of plasmonic structures so far, by integrated with Si nanogrooves. Meanwhile, the scattering of the coupled nanostructure exhibits an angle-dependent polarization state, which can be further applied to information encryption. These findings have shown that this strategy can not only efficiently capture light, but also exhibit angle-dependent polarization states, which building an impregnable barrier for future quantum encrypted communications.

DNA nanotechnology has attracted intense interest in biomedicine due to the advantages of good biocompatibility, structural programmability and multifunctionality. Herein, a DNA-Au nanomachine with active/passive dual-targeting capacity has been constructed, achieving lysosomal acidic microenvironment-activated combinational chemo-photothermal therapy of cervical carcinoma. The three-dimensional DNA nanoflowers (DNFs) are readily prepared via rolling circle amplification (RCA), in which the active targeting units (C-9S aptamers) for HeLa cells and drug-loading sites for doxorubicin (Dox) are rationally designed in the circular template. Meanwhile, the bovine serum albumin (BSA)-modified gold nanoparticles (BSA-AuNPs) with pH-responsive charge reversal ability are internalized into cancer cells through passive targeting mechanism of enhanced permeability and retention (EPR) effect. Under acidic stimuli (endosome and lysosome), the loaded Dox in DNFs is controllably released for targeted chemotherapy, and the charge of BSA-AuNPs is reversed from negative to positive in lysosome, resulting in the aggregation of BSA-AuNPs on DNFs through electrostatic interaction. Thus, hyperthermia is produced upon 808 nm laser irradiation for photothermal therapy (PTT). The in vitro and in vivo results demonstrate the highly chemo-photothermal therapy effect on cervical cancer based on the proposed DNA-Au nanomachine, providing a powerful and potential nanotheranostic platform for targeted combinational therapy of cancers in clinical applications.

Nanozymes are nanomaterials with intrinsic enzyme-like properties. Since the landmark research report on nanozymes in 2007, numerous scientists focus on the topic of nanozyme. As an artificial enzyme, nanozymes take advantage of good stability, easy modification, designability, ease of preparation, and low cost. In recent years, due to the explosion of nanotechnology, biomimetic science, catalytic science, and theoretical computing, a great number of nanozymes have been fabricated. To highlight these achievements and allow the related researchers to grasp the current research status of structure-dependent nanozymes, the state-of-the-art in nanozymes from different spatial dimensions (0D, 1D, 2D, 3D) to the bioanalysis applications were reviewed. For different spatial dimensions nanozymes, the 0D nanodot, nanosphere, nanocluster; 1D nanorod, nanotube, 2D nanosheet, lamellar structure, and 3D metal-organic frameworks, covalent organic frameworks, hierarchical structure, and hydrogel were all discussed. Furthermore, the nanozymes applied for disease diagnosis, tumor microenvironment sensing, pathogen detection, drug detection, food detection, and environmental sensing were all discussed. Finally, the current challenges faced in nanozymology are outlined and the future directions for advancing nanozyme research are outlooked. We hope this review will inspire related research on nanozymes and contribute to developing nanozymes in bioanalysis.

Resistive random access memories (RRAMs) using two-dimensional (2D) materials have delivered comparable switching performance with CMOS devices. However, devices risk short problems because of their ultra-thin body, thus yielding poorly. In this study, we realize high-yield RRAMs thanks to the synthesis of uniform large-area multilayer molybdenum disulfide by thermally decomposing ammonium tetrathiomolybdate. This top-down method has advantages over mainstream chemical vapor deposition, in which layer-by-layer epitaxy is forbidden when surface energy elevates. The resulting film surface roughness is down to 93.8 pm, and its lateral size can be scaled up to wafer scale. A yield value higher than 90% was estimated by testing 8 × 8 RRAM arrays, reaching nearly 100% in isolated devices. These devices show low operation voltages (∼1V) with low cycle-to-cycle and device-to-device variations (∼12%). We also observed stable resistive switching of multilayer films prepared at 400 °C. The large-area synthesis of uniform multilayer films makes it more feasible to use 2D semiconductors in practical RRAM technology for wafer-scale integration.

Efficiently harvesting solar energy into electricity via photovoltaic devices (also called solar cells) exhibits a feasible way to tackle challenging energy supply. Over the past decades, crystal silicon (c-Si) is still the dominant material for photovoltaic manufacture, benefiting from its nearly ideal optical bandgap, abundant, and mature semiconductor technology. Up to now, the power conversion efficiency of single-junction c-Si solar cells with heterojunction structures has been boosted to over 26%, approaching its theoretical maximum efficiency. On the other hand, a trade-off of the cost/output power of heterojunction cells is still an obstacle to its expanding market share. Being different from any previous scalable c-Si photovoltaic generations, the heterojunction cell features uniquely indispensable transparent conducting oxide (TCO) layers integrating a low-temperature annealing metal paste. Its unique electrode requirement is still the dominant factor to determine its rate of exposure mass manufacture. In this review, the field of TCO development of silicon heterojunction (SHJ) solar cells is overviewed firstly. Furthermore, different TCO choices for SHJ solar cells are discussed. Finally, future research directions, challenges, and potential solutions are summarized and looked forward. To conclude, we discuss what has been taken for the TCO application for SHJ solar cells in the mass market.

Recently, optical chemical sensors have been used to simplify traditional methods of chemical analyses. Indeed, sensing strategies based on the photoluminescence properties of nanomaterials need to be well-understood, since there are several nanomaterials with different features regarding their applicability in the optical sensor field. This review summarizes the main 0D, 1D and 2D nanomaterials used in sensing devices, with a special look in their optical properties and different methods of synthesis, as well as a briefing overview related to their colloidal stability, chemical structure and kinetic and thermodynamic parameters. In addition, the analytical performances of different optical sensing strategies are also highlighted, in which pattern recognition algorithms and the development of polymeric-based films are tools used to contribute for the application of new optical chemical sensors with exceptional sensibility and selectivity. Furthermore, this review would give some insights into advances development of optical chemical sensors, using nanomaterials of different dimensionalities.

The potential applications of two-dimensional (2D) materials-based devices in various fields have garnered significant interest. However, the limited heat transfer efficiency across the interface between 2D materials and the substrate has impeded their widespread application. This study presents a novel approach to enhancing the interface thermal transport of a widely used graphene/substrate structure through repeated annealing. Using Raman thermometry, we measured the interface thermal resistance (R) at 9.51 × 10-5 m2⋅K/W, which was subsequently reduced by an order of magnitude to 5.00 × 10-6 m2⋅K/W after repeated annealing. Our experimental results, supported by atomic modelling, revealed the significant influence of wrinkles on the interface thermal transport. Atomic force microscopy (AFM) images vividly illustrate the modulation of the surface structure due to repeated annealing, with the initial loose structure becoming tighter and the wrinkle flattened. Further phonon transport analysis revealed a significantly reduced phonon coupling rate between graphene and SiO2 due to the presence of wrinkles in the graphene. Our findings highlight the feasibility of annealing as a means of manipulating interface thermal transport and provide insights into the underlying mechanism, which may inspire further studies on enhancing thermal interface properties.

Acoustic microfluidics has a remarkable influence on mixing but still face significant challenges of low throughput. Here, a robust acoustic micromixer with a spiral microchannel and side-wall sharp-edge structures is first proposed for facilitating microscale fluid mixing at wide-range flow rates. A micromixer that integrates acoustics with hydrodynamics enables fast and homogeneous mixing, ranging from 4 μL/min to over 2500 μL/min. the mixing performance shows a transition from acoustics domination at low flow rates to hydrodynamics domination at high flow rates. The increases of transducer amplitude, curvature, and sharp-edge density are positively correlated with mixing performance, while the increase of a tilted angle shows the opposite. The acoustic micromixer is leveraged to synthesize a functional ZnO nanoarray inside glass capillaries as portable microanalytical systems. ZnO nanofiber and nanosheet arrays are developed and their performances are systematically investigated by photodegradation of organic dye and enrichment of a heavy metal ion. Generally, efficiencies in photodegradation and enrichment can be well regulated by residence time, and a ZnO nanofiber shows more outstanding activity and robust stability than a ZnO nanosheet. These findings not only shed new light on the rational design of advanced lab-on-a-chip devices but also provide important guidelines for the controllable synthesis and applications of functional nanomaterials.