Transpiration-Inspired Fabric Dressing for Acceleration Healing of Wound Infected with Biofilm.

In chronic wound management, efficacious handling of exudate and bacterial infections stands as a paramount challenge. Here a novel biomimetic fabric, inspired by the natural transpiration mechanisms in plants, is introduced. Uniquely, the fabric combines a commercial polyethylene terephthalate (PET) fabric with asymmetrically grown 1D rutile titanium dioxide (TiO2) micro/nanostructures, emulating critical plant features: hierarchically porous networks and hydrophilic water conduction channels. This structure endows the fabric with exceptional antigravity wicking-evaporation performance, evidenced by a 780% one-way transport capability and a 0.75 g h-1 water evaporation rate, which significantly surpasses that of conventional moisture-wicking textiles. Moreover, the incorporated 1D rutile TiO2 micro/nanostructures present solar-light induced antibacterial activity, crucial for disrupting and eradicating wound biofilms. The biomimetic transpiration fabric is employed to drain exudate and eradicate biofilms in Staphylococcus aureus (S. aureus)-infected wounds, demonstrating a much faster infection eradication capability compared to clinically common ciprofloxacin irrigation. These findings illuminate the path for developing high-performance, textile-based wound dressings, offering efficient clinical platforms to combat biofilms associated with chronic wounds.

Silver nanoparticles decorated meta-aramid nanofibrous membrane with advantageous properties for high-performance flexible pressure sensor.

Flexible pressure sensors have received tremendous attention for various wearable applications. However, it remains a critical challenge to develop a flexible pressure sensor with excellent sensitivity performances and multiple advantageous properties. Herein, a high-performance flexible piezoresistive pressure sensor PMIA@PDA@Ag was developed, which sensitive component is consisted of Ag nanoparticles decorated polydopamine (PDA)-modified meta-aramid (poly(m-phenylene isophthalamide), PMIA) nanofibrous membrane. The PMIA@PDA@Ag pressure sensor shows excellent mechanical, thermal insulation, antibacterial and breathable properties, as well as remarkable sensing performances including high sensitivity, wide detectable pressure range, rapid response speed and good cyclic durability. In addition, it also shows great sensing performances in monitoring various human behaviors in real-time, including large-scale motions and subtle physiological signals.

Fabrication of complex, 3D, branched hollow carbonaceous structures and their applications for supercapacitors.

A unique "integrated hard-templating strategy" is described for facile synthesis of a carbonaceous material with a novel three-dimensional (3D) branched hollow architecture. A set of steps, including template formation, surface coating and template removal, all occur in a spontaneous and orderly manner in the one-pot hydrothermal process. Investigations on structural evolution during the process reveal that pre-synthesized zeolitic imidazolate framework-8 (ZIF-8) nanoparticles are first dissociated and then self-assembled into 3D branched superstructures of ZnO as templates. Initial self-assembly is followed by coating of the glucose-derived carbonaceous materials and etching of interior ZnO by organic acids released in situ by hydrolysis of glucose. The 3D-branched hollow architecture is shown to greatly enhance supercapacitor performance. The research described here provides guidance into the development of strategies for complex hollow carbonaceous architectures for a variety of potential applications.

Superaerophobic copper-based nanowires array for efficient nitrogen reduction.

Electrocatalytic N2 reduction reaction (NRR) provides a promising route for NH3 production under ambient conditions to replace traditional Haber-Bosch process. For this purpose, efficient NRR electrocatalysts with high NH3 yield rate and high Faradaic efficiency (FE) are required. Cu-based materials have been recognized catalytic active for some multi-electron-involved reduction reactions and usually exhibit inferior catalytic activities for hydrogen evolution reaction. We report here the preparation and characterization of a series of Cu-based nanowires array (NA) catalysts in situ grown on Cu foam (CF) substrate, including Cu(OH)2 NA/CF, Cu3N NA/CF, Cu3P NA/CF, CuO NA/CF and Cu NA/CF, which are directly used as self-supported catalytic electrodes for NRR. The electrochemical results show that CuO NA/CF achieves a highest NH3 yield rate of 1.84 × 10-9 mol s-1 cm-2, whereas Cu NA/CF possesses a highest FE of 18.2% for NH3 production at -0.1 V versus reversible hydrogen electrode in 0.1 M Na2SO4. Such catalytic performances are superior to most of recently reported metal-based NRR electrocatalysts. The contact angle measurements and the simulated calculations are carried out to reveal the important role of the superaerophobic NA surface structure for efficient NRR electrocatalysis.

Multifunctional Textiles Based on Three-Dimensional Hierarchically Structured TiO2 Nanowires.

The development of three-dimensional (3D) micro-/nanostructures with multiscale hierarchy offers new potential for the improvement of the pristine textile properties. In this work, a polyester fabric coated with 3D hierarchically structured rutile TiO2 nanowires (THNWP) was fabricated by a facile hydrothermal strategy. The THNWP samples exhibit markedly improved photocatalytic activities and antibacterial properties owing to their 3D hierarchical architecture constructed by one-dimensional nanowire structures, good crystallinity, excellent light-harvesting capability, and fast electron-transfer rate. Furthermore, the unique 3D hierarchical nanostructures also combine with the monofilament to produce ternary-scale hierarchy, which endows the fabric surface with outstanding superamphiphobicity after further facile fluorination treatment. The supportive air-pockets trapped within the unique ternary-scale architectures are proved to be the crucial factor in the achievement of high liquid repellency, and the highest performing superamphiphobic surface is capable of repelling liquids down to a minimal surface tension of 23.4 mN m-1. We envision that our findings may possess great potential in the bottom-up design of high-performance textiles.

Designing Re-Entrant Geometry: Construction of a Superamphiphobic Surface with Large-Sized Particles.

Re-entrant geometries can effectively trap air pockets beneath coating surfaces, prevent the penetration of low surface tension organic liquids, and achieve superamphiphobic performance. However, the creation of re-entrant geometries through particle-based spray coating remains a challenge. In the past decade, various studies have focused on the preparation of superamphiphobic coatings using ultrafine nanoparticles (10-15 nm) using conventional spray-coating methods. In this work, we aim to fabricate a spray-coated superamphiphobic surface using large particles with a hierarchical structure. The study systematically investigated the wetting behaviors of liquids with different topographies obtained using large particles (i.e., smooth, micro, nano, and micro/nanostructures) by different coating methods. The findings suggested that compared with the typical colloid template method, the surface obtained using the spray-coating method showed much greater roughness, which greatly enhanced the oleophobicity of the coating. Furthermore, only hierarchically monodisperse hollow SiO2 spheres (MDH-SiO2) showed excellent superamphiphobicity, which was independent of the hollow sphere size. While maintaining the coating roughness, by applying solid C@SiO2 as a reference sample, the important role of the hollow structure of MDH-SiO2 at the solid-liquid-air interface was confirmed. Nanosphere-surrounded hollow structures were shown to serve as a re-entrant type structure, preventing the imbibition of the liquid, finally leading to a stable Cassie state. This design strategy may provide useful guidelines for the fabrication of large particle-based spray-coated superamphiphobic surfaces.

Crucial role of an aerophobic substrate in bubble-propelled nanomotor aggregation.

A bubble-propelled autonomous micro/nanomotor (MNM) is a device driven by a catalytic reaction that involves a solid-liquid-gas interface, which in turn is a key factor in achieving effective propulsion. Generally, modifying the liquid phase by adding surfactants can improve propulsion, but it has several disadvantages. It is reported that the rapid separation of bubbles will accelerate the movement of MNMs. Our focus is on methods to drive the motor efficiently by controlling the wettability of the solid phase, accelerating bubble separation without compromising the activity of the catalyst. In this study, different from most of the previous studies on moving MNMs, a static Pt loaded TiO2 nanowire aggregation was utilized as a nanomotor aggregation to investigate the wettability of the solid phase on bubble release. In comparison to an underwater aerophilic solid phase, in which bubbles are strongly held on the surface, the nanomotor's aggregation showed good aerophobicity. In particular, after UV illumination for 30 s, the nanomotor's aggregation became superaerophobic, which significantly promoted the release of O2 bubbles. The results of this study reveal how to modify the detachment behaviour of bubbles by controlling the aerophobic behaviour of solid surfaces of autonomous MNMs in an aqueous medium.

Walnut-like Transition Metal Carbides with Three-Dimensional Networks by a Versatile Electropolymerization-Assisted Method for Efficient Hydrogen Evolution.

Mo2C@NPC (N,P-doped carbon) electrocatalysts are developed on carbon cloth (CC) as binder-free cathodes for efficient hydrogen evolution through a facile route of electropolymerization followed by pyrolysis. Electropolymerization of pyrrole to form polypyrrole occurs with the homogeneous incorporation of PMo12, driven by Coulombic force between the positively charged polymer backbone and PMo12 anions. This electrochemical synthesis is easily scaled up, requiring neither complex instrumentation nor an intentionally added electrolyte (PMo12 also acts as an electrolyte). After pyrolysis, the resultant Mo2C@NPC/CC electrode exhibits a unique interconnected walnut-like porous structure, which ensures strong adhesion between the active material and the substrate and favors electrolyte penetration into the electrocatalyst. This method is effective with other monomers such as aniline and is readily extended to fabricate other metal carbide electrodes such as WC@NPC/CC. These carbide electrodes exhibit high catalytic performance for hydrogen production, for example, WC@NPC/CC can deliver an unprecedented current density of 600 mA cm-2 at an overpotential of only 200 mV either in an acidic or an alkaline solution. Considering the simplicity, scalability, and versatility of the synthetic method, the unique electrode structure, and the excellent catalysis performance, this study opens up new avenues for the design of various novel binder-free metal carbide cathodes based on electropolymerization.

Multiscale porous molybdenum phosphide of honeycomb structure for highly efficient hydrogen evolution.

The hydrogen evolution reaction (HER) based on electrochemical water splitting is considered a promising strategy to produce clean and sustainable hydrogen energy. Searching for non-noble metal based electrocatalysts with high efficiency and durability toward the HER is vitally necessary. In this work, we report a novel method for synthesizing molybdenum phosphide (MoP) supported on multiscale porous honeycomb carbon (MoP@HCC) and the application of this catalyst material in acidic media for water electrolysis. Due to the unique structure of the catalyst material, the as-prepared MoP@HCC shows remarkable electrocatalytic activity and stability in 0.5 M H2SO4 aqueous solution. The hybrid catalyst could deliver a current density of 10 mA cm-2 at a low overpotential of 129 mV, with an onset overpotential of 69 mV and a Tafel slope of 48 mV dec-1, outperforming most of the current noble-metal-free electrocatalysts. This study demonstrates an effective way for multiscale control of the MoP structure via overall consideration of the mass transport, and the accessibility, quantity and capability of active sites toward the HER.

Ni nanotube array-based electrodes by electrochemical alloying and de-alloying for efficient water splitting.

The design of cost-efficient earth-abundant catalysts with superior performance for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is extremely important for future renewable energy production. Herein, we report a facile strategy for constructing Ni nanotube arrays (NTAs) on a Ni foam (NF) substrate through cathodic deposition of NiCu alloy followed by anodic stripping of metallic Cu. Based on Ni NTAs, the as-prepared NiSe2 NTA electrode by NiSe2 electrodeposition and the NiFeOx NTA electrode by dipping in Fe3+ solution exhibit excellent HER and OER performance in alkaline conditions. In these systems, Ni NTAs act as a binder-free multifunctional inner layer to support the electrocatalysts, offer a large specific surface area and serve as a fast electron transport pathway. Moreover, an alkaline electrolyzer has been constructed using NiFeOx NTAs as the anode and NiSe2 NTAs as the cathode, which only demands a cell voltage of 1.78 V to deliver a water-splitting current density of 500 mA cm-2, and demonstrates remarkable stability during long-term electrolysis. This work provides an attractive method for the design and fabrication of nanotube array-based catalyst electrodes for highly efficient water-splitting.

N,P-Doped Molybdenum Carbide Nanofibers for Efficient Hydrogen Production.

Molybdenum (Mo) carbide-based electrocatalysts are considered promising candidates to replace Pt-based materials toward the hydrogen evolution reaction (HER). Among different crystal phases of Mo carbides, although Mo2C exhibits the highest catalytic performance, the activity is still restricted by the strong Mo-H bonding. To weaken the strong Mo-H bonding, creating abundant Mo2C/MoC interfaces and/or doping a proper amount of electron-rich (such as N and P) dopants into the Mo2C crystal lattice are effective because of the electron transfer from Mo to surrounding C in carbides and/or N/P dopants. In addition, Mo carbides with well-defined nanostructures, such as one-dimensional nanostructure, are desirable to achieve abundant catalytic active sites. Herein, well-defined N,P-codoped Mo2C/MoC nanofibers (N,P-Mo xC NF) were prepared by pyrolysis of phosphomolybdic ([PMo12O40]3-, PMo12) acid-doped polyaniline nanofibers at 900 °C under an Ar atmosphere, in which the hybrid polymeric precursor was synthesized via a facile interfacial polymerization method. The experimental results indicate that the judicious choice of pyrolysis temperature is essential for creating abundant Mo2C/MoC interfaces and regulating the N,P-doping level in both Mo carbides and carbon matrixes, which leads to optimized electronic properties for accelerating HER kinetics. As a result, N,P-Mo xC NF exhibits excellent HER catalytic activity in both acidic and alkaline media. It requires an overpotential of only 107 and 135 mV to reach a current density of 10 mA cm-2 in 0.5 M H2SO4 and 1 M KOH, respectively, which is comparable and even superior to the best of Mo carbide-based electrocatalysts and other noble metal-free electrocatalysts.

Nickel-Based (Photo)Electrocatalysts for Hydrogen Production.

Hydrogen is considered a promising energy carrier for replacing traditional fossil fuels. Electrochemical or solar-driven water splitting is a green and sustainable method of producing hydrogen. To lower the overpotential and minimize energy costs, numerous reports have focused on developing noble-metal-free catalysts for hydrogen production, with special attention paid to nickel-based materials. Herein, the current state of research on the use of Ni-based materials as electrocatalysts, cocatalysts, and photoactive materials in hydrogen production is reviewed. Recent research efforts toward the development of various Ni-based (photo)electrocatalysts, their applications in hydrogen production, and the corresponding mechanisms are covered. The approaches used to improve or optimize these materials are summarized, and the key remaining challenges are discussed.

A Highly Active and Robust Copper-Based Electrocatalyst toward Hydrogen Evolution Reaction with Low Overpotential in Neutral Solution.

Although significant progress has been made recently, copper-based materials have long been considered to be ineffective catalysts toward the hydrogen evolution reaction (HER), in most cases, requiring high overpotentials more than 300 mV. We report here that a Cu(0)-based nanoparticle film electrodeposited in situ from a Cu(II) oxime complex can act as a highly active and robust HER electrocatalyst in neutral phosphate buffer solution. The as-prepared nanoparticle film is of poor crystallization, which incorporates significant amounts of oxime ligand residues and buffer anions PO43-. The proposed mechanism suggests that the Cu(0)-based nanoparticle film is activated with incorporated or adsorbed PO43- anions and the PO43- anions-anchored sites might serve as the actual catalytic active sites with efficient proton transport mediators. Catalysis occurs with a low onset overpotential (η) of 65 mV, and a current density of 1 mA/cm2 can be achieved with η = 120 mV. The nanoparticle film shows an excellent catalytic durability with slightly rising current density during electrolysis, presumably due to further incorporation or adsorption of PO43- anions in the process. This electrocatalyst not only forms in situ from earth-abundant materials but also operates in neutral water with low overpotential and high stability.

A fast electrochromic polymer based on TEMPO substituted polytriphenylamine.

A novel strategy to obtain rapid electrochromic switching response by introducing 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) moiety into polytriphenylamine backbone has been developed. The electrochromic properties of the integrated polymer film are investigated and a possible mechanism is proposed with TEMPO as a counterion-reservoir group to rapidly balance the charges during electrochromic switching, which leads to significantly improved electrochromism performance.

Crystal structure of di-bromido-tetra-kis(propan-2-ol-κO)nickel(II).

The asymmetric unit of the mononuclear title complex, [NiBr2(C3H8O)4], comprises a Ni(II) cation located on a centre of inversion, one Br(-) anion and two propan-2-ol ligands. The Ni(II) cation exhibits a distorted trans-Br2O4 environment. There are O-H⋯Br hydrogen bonds connecting neighbouring mol-ecules into rows along [100]. These rows are arranged in a distorted hexa-gonal packing and are held together by van der Waals forces only.