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Introduction: Two-dimensional (2D) materials, such as MXene (Ti3C2Tx), have garnered extensive attention in recent years due to their exceptional performance across various domains. The flake size of Ti3C2Txnotably influences its specific surface area, a pivotal factor in interfacial interactions within electrochemistry.Method: Presently, modifying the flake size of bulk Ti3C2Txtypically involves complex and costly processes, like ultrasonic treatment and isolation. Leveraging the specific preparation principle of MXenes, which involves etching the A layers in precursor MAX phases, a topdown strategy for producing Ti3C2Txflakes of desired sizes, has been proposed in this work. In this approach, precursor Ti3AlC2 particles undergo ball-milling to adjust their size.Result: Through this innovative strategy, dispersions of Ti3C2Txflakes with varying average lateral sizes are generated, enabling an investigation into the impact of lateral size on the electrochemical properties of Ti3C2Txflakes. By controlling the ball milling time for Ti3AlC2powders, the resulting average sizes of Ti3C2Tx(0, 2, 4) are 6.34 µm, 2.16 µm, and 0.96 µm, respectively. Particularly, the Ti3C2Tx(2) electrode, composed of 2.16 µm sheets, demonstrates remarkable performance metrics. It exhibits a high areal capacitance of 845.0 mF/cm2at a scan rate of 5 mV/s, along with a gravimetric capacitance of 244.0 F/g at a current density of 1 A/g.Conclusion: This study presents a facile method to enable mass production of Ti3C2Txwith sheets of varying sizes, addressing both small and large dimensions.

Amyloid-β 1-42 (Aβ42) plays a pivotal role in Alzheimer disease (AD) pathogenesis. Peripheral clearance of Aβ42 largely affects its level in the brain and affects AD progression. Although nattokinase (NK) degrades Aβ40, the details of NK’s capture of various Aβ species and reduction of plasma Aβ42/Aβ40 are uncharacterized. In this study, the Aβ42/Aβ40-degrading ability of NK was investigated using five Aβs and AD model mice. The C-terminal region of Aβ42/Aβ40 (Gly29 to Val40) was primarily required for NK capture, and the integrated conformation in Aβ42/Aβ40 aggregates was a more efficient target for NK catalysis. Further, suspended Aβ42/Aβ40 oligomers were more easily captured by NK than suspended Aβ42/Aβ40 fibrils, while deposited Aβ42/Aβ40 fibrils recruited more NK than deposited Aβ42/Aβ40 oligomers. Although most NK was likely lost during NK uptake and/or entry into the blood, a small fraction of NK showed good plasma Aβ42/Aβ40-degrading efficacy after entering the blood due to NK’s stability in the plasma of AD mice for at least 9 days. It was concluded that oral administration of NK is a feasible approach for peripheral Aβ42/Aβ40 clearance. This implies that NK might serve as an anti-Aβ42 agent for the treatment of Aβ42/Aβ40-related diseases such as AD.

MXene, a promising electrode material for supercapacitors, has excellent mechanical properties, hydrophilicity, metallic conductivity, and rich surface chemistry. However, the self-restacking of MXene nanosheets due to the strong van der Waals force makes it difficult to assemble them into electrodes. Here, continuous, ultrathin carbon nanotube (CNT) films are introduced as interlayers between MXene layers to prevent self-restacking during the assembly process, and freeze-drying is used to obtain composite films with a layered porous structure. The MXene/CNT composite films exhibit excellent electrochemical performance, and the film asymmetric device based on them delivers an energy density of 7.34 Wh kg–1at a power density of 50 W kg–1. Moreover, these composite films demonstrate good flexibility and can be spun into fibers to assemble symmetric supercapacitors, showing good cyclic stability with a capacitance retention up to 99% over 5000 cycles. These MXene/CNT composite film electrodes can work under different forms (films or fibers) and have potential applications as flexible and wearable energy storage devices and textiles.

Developing a cost-effective hydrogen (H2) evolution electrocatalyst can effectively solve the problem of environmental pollution caused by excessive fossil fuel use. Herein, we report an innovative synthetic strategy, involving hydrothermal electrodeposition of a NiCoZn film on commercial carbon fiber paper (CFP) and in situ cyclic voltammetric electrodeposition of NiMoP to prepare a heterostructure electrocatalyst (NiMoP/NiCoZn/CFP) with synergistic electrocatalytic activity toward the hydrogen evolution reaction (HER). To deliver high current densities of 500 and 1000 mA cm–2, the NiMoP/NiCoZn/CFP electrode only required overpotentials of 230 and 268 mV, respectively, which were considerably superior to those of Pt–C/CFP (457 and 592 mV, respectively). Moreover, this electrode exhibited excellent ultrastability (40 h at 500 mA cm–2or 80 h at 1 A cm–2). The superior electrocatalytic HER activity is attributed to (1) cooperative electronic interactions between NiMoP and NiCoZn in the heterointerface and (2) the complete wettability, which is advantageous for gas formation and desorption and considerably reduces bubble adhesion and reaction resistance. This work provides a rational electrodeposition strategy for constructing heterointerface electrocatalysts for H2production at high current densities.

Recently, room-temperature flexible gas sensors have been widely studied because they can operate without being heated and create low-cost, low-power-consumption devices with long-term stability. Here, by designing the active material composition and structure, we report an electrospun carbon nanofiber (CNF) network grafted by two-dimensional MoS2nanosheets and embedded CoS2nanoparticles, which serves as a flexible gas sensor for various toxic or hazardous gases working at room temperature. In particular, the CNFs/CoS2/MoS2hybrid films exhibit very high selectivity toward NO over other gases including NO2and CH4, with selectivity coefficients (|SNO/SNO2| and |SNO/SCH4|) as high as 43 and 42 (defined as the ratio of responses between two gases). The sensor shows a linear relationship in the gas concentration range of 1–100 ppm and a stable response during repeated bending. Theoretical calculations suggest that MoS2can be selectively n-doped by NO, while CoS2can effectively capture NO molecules, leading to enhanced selectivity and sensitivity. Our large-area flexible sensors made by synergistic design have potential applications in biological and environmental areas for low-cost, selective detection of toxic or targeted gases.

Some synthesis methods to fabricate one-dimensional nanomaterials, including template-assisted growth, simple catalyst-free growth and chemical vapor deposition, and the characterization methods by transmission electron microscopy, for example, determination of mechanical properties of ceramic nanowires and helicity distribution of bundles of single-walled carbon nanotubes are reported and discussed.

Preparation of high-efficiency dual-functional catalysts remains the bottleneck for electrochemical water splitting. To prepare a non-precious metal catalyst with high activity and stability, here, we present a seaweed-like structure consisting of transition-metal sulfide nanoplates self-assembled on carbon nanotube sponge networks (SW-CoS@CNT). By adjusting the key parameters during synthesis (e.g., the loading amount and ratio of Co and S precursors), the microstructure can be tailored in a wide range, and sulfur defects can be introduced into the nanoplates by thermal annealing. The resulting SW-CoS@CNT serves as a freestanding dual-functional catalytic electrode, showing low overpotentials of 105 and 218 mV for the hydrogen evolution reaction and the oxygen evolution reaction, respectively, which are superior to most reported transition-metal-sulfide-based catalysts in alkaline solution. Rational design of this hierarchical biomimetic structure may be useful in developing high-performance electrochemical catalysts in renewable energy and environmental fields.

Crystalline boron nanowires with tetragonal structure have been synthesized based on laser ablation of a B/NiCo target; the nanowires are sometimes single crystals and have a droplet at one end of the nanowire; the droplet contains B, Ni and Co elements, which indicates that the vapor–liquid–solid (VLS) mechanism may play a key role in the growth of the boron nanowires.

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