The true promise of MXene as a practical supercapacitor electrode hinges on the simultaneous advancement of its three-dimensional (3D) assembly and the engineering of its nanoscopic architecture, two critical factors for facilitating mass transport and enhancing an electrode’s charge-storage performance. Herein, we present a straightforward strategy to engineer robust 3D freestanding MXene (Ti₃C₂T_x) hydrogels with hierarchically porous structures. The tetraamminezinc(II) complex cation ([Zn(NH₃)₄]²⁺) is selected to electrostatically assemble colloidal MXene nanosheets into a 3D interconnected hydrogel framework, followed by a mild oxidative acid-etching process to create nanoholes on the MXene surface. These hierarchically porous, conductive holey-MXene frameworks facilitate 3D transport of both electrons and electrolyte ions to deliver an excellent specific capacitance of 359.2 F g^–1 at 10 mV s^–1 and superb capacitance retention of 79% at 5000 mV s^–1, representing a 42.2% and 15.3% improvement over pristine MXene hydrogel, respectively. Even at a commercial-standard mass loading of 10.1 mg cm^–2, it maintains an impressive capacitance retention of 52% at 1000 mV s^–1. This rational design of an electrode by engineering nanoholes on MXene nanosheets within a 3D porous framework dictates a significant step forward toward the practical use of MXene and other 2D materials in electrochemical energy storage systems. 

Given the abundant solar light available on our planet, it is promising to develop an advanced fabric capable of simultaneously providing personal thermal management and facilitating clean water production in an energy-efficient manner. In this study, we present the fabrication of a photothermally active, biodegradable composite cloth composed of titanium carbide MXene and cellulose, achieved through an electrospinning method. This composite cloth exhibits favorable attributes, including chemical stability, mechanical performance, structural flexibility, and wettability. Notably, our 0.1-mm-thick composite cloth (RC/MXene IV) raises the temperature of simulated skin by 5.6 degrees C when compared to a commercially available cotton cloth, which is five times thicker under identical ambient conditions. Remarkably, the composite cloth (RC/MXene V) demonstrates heightened solar light capture efficiency (87.7%) when in a wet state instead of a dry state. Consequently, this cloth functions exceptionally well as a high-performance steam generator, boasting a superior water evaporation rate of 1.34 kg m(-2) h(-1) under one-sun irradiation (equivalent to 1000 W m(-2)). Moreover, it maintains its performance excellence in solar desalination processes. The multifunctionality of these cloths opens doors to a diverse array of outdoor applications, including solar-driven water evaporation and personal heating, thereby enriching the scope of integrated functionalities for textiles.

Understanding the reconstruction of surface sites is crucial for gaining insights into the true active sites and catalytic mechanisms. While extensive research has been conducted on reconstruction behaviors of atomically dispersed metallic catalytic sites, limited attention has been paid to non-metallic ones despite their potential catalytic activity comparable or even superior to their noble-metal counterpart. Herein, we report a carbonaceous, atomically dispersed non-metallic selenium catalyst that displayed exceptional catalytic activity in the hydrazine oxidation reaction (HzOR) in alkaline media, outperforming the noble-metal Pt catalysts. In situ X-ray absorption spectroscopy (XAS) and Fourier transform infrared spectroscopy revealed that the pristine SeC₄ site pre-adsorbs an ∗OH ligand, followed by HzOR occurring on the other side of the OH–SeC₄. Theoretical calculations proposed that the pre-adsorbed ∗OH group pulls electrons from the Se site, resulting in a more positively charged Se and a higher polarity of Se–C bonds, thereby enhancing surface reactivity toward HzO/R.

Background: As a promising green energy conversion device, direct ethylene glycol fuel cells (DEGFC) have been widely studied. But high-cost of their catalysts has severely limited large-scale commercial application. Developing economic and effective anodic electrocatalyst is an urgent work presently.

Methods: Herein, an efficient high entropy alloy catalyst (HEA, penta-element) was prepared. Then, their catalytic performance and properties were authenticated by some electrochemical and physical methods. Importantly, it was also applied to a real DEGFC stack.

Significant findings: Notably, the ethylene glycol oxidation current density (0.65 A mg⁻¹_PtPdAu) on as-prepared HEA is three times than that of commercial Pt/C (0.22 A mg⁻¹_Pt) with good long-term durability. Moreover, the HEA-equipped DEGFC obtains an open circuit potential of 0.58 V, which delivers 2 times larger peak power density (17.63 mW cm⁻²) than that of commercial Pt/C (7.37 mW cm⁻²). This work would be a good reference to developing other advanced HEA materials in electrocatalytic fields.

Two-dimensional (2D) membrane-based ion separation technology has been increasingly explored to address the problem of lithium resource shortage, yet it remains a sound challenge to design 2D membranes of high selectivity and permeability for ion separation applications. Zeolitic imidazolate framework functionalized modified layered double hydroxide (ZIF-8@MLDH) composite membranes with high lithium-ion (Li⁺) permeability and excellent operational stability were obtained in this work by in situ depositing functional ZIF-8 nanoparticles into the nanopores acting as framework defects in MLDH membranes. The defect-rich framework amplified the permeability of Li⁺, and the site-selective growth of ZIF-8 in the framework defects bettered its selectivity. Specifically speaking, the ZIF-8@MLDH membranes featured a high permeation rate of Li⁺ up to 1.73 mol m⁻² h⁻¹ and a desirable selectivity of Li⁺/Mg²⁺ up to 31.9. Simulations supported that the simultaneously enhanced selectivity and permeability of Li⁺ are attributed to changes in the type of mass transfer channels and the difference in the dehydration capacity of hydrated metal cations when they pass through nanochannels of ZIF-8. This study will inspire the ongoing research of high-performance 2D membranes through the engineering of defects.

Fe₃C nanoparticles hold promise as catalysts and nanozymes, but their low activity and complex preparation have hindered their use. Herein, this study presents a synthetic alternative toward efficient, durable, and recyclable, Fe₃C-nanoparticle-encapsulated nitrogen-doped hierarchically porous carbon membranes (Fe₃C/N–C). By employing a simple one-step synthetic method, we utilized wood as a renewable and environmentally friendly carbon precursor, coupled with poly(ionic liquids) as a nitrogen and iron source. This innovative strategy offers sustainable, high-performance catalysts with improved stability and reusability. The Fe₃C/N–C exhibits an outstanding peroxidase-like catalytic activity toward the oxidation of 3,3′,5,5′-tetramethylbenzidine in the presence of hydrogen peroxide, which stems from well-dispersed, small Fe₃C nanoparticles jointly with the structurally unique micro-/macroporous N–C membrane. Owing to the remarkable catalytic activity for mimicking peroxidase, an efficient and sensitive colorimetric method for detecting ascorbic acid over a broad concentration range with a low limit of detection (~2.64 µM), as well as superior selectivity, and anti-interference capability has been developed. This study offers a widely adaptable and sustainable way to synthesize an Fe₃C/N–C membrane as an easy-to-handle, convenient, and recoverable biomimetic enzyme with excellent catalytic performance, providing a convenient and sensitive colorimetric technique for potential applications in medicine, biosensing, and environmental fields.

Two-dimensional (2D) MXene-based lamellar membranes play transformative roles in membrane filtration technology. Their practical use in water treatment is however hindered by several hurdles, e.g., unfavorable swelling due to weak interactions between adjacent MXene nanosheets, tortuous diffusion pathways of layered stacking, and the intrinsic aquatic oxidation-prone nature of MXene. Herein, nanoporous 2D/2D heterostructure membranes are elaborately constructed via solution-phase assembly of oppositely charged MXene and modified layered double hydroxide (MLDH) nanosheets. As a multifunctional component, positively charged holey MLDH nanosheets were first tailor-made to serve simultaneously as a binder, spacer and surface-modifier; next they were intercalated into negatively charged MXene lamella to enhance structural stability and mass transfer of membranes. As a result, the as-prepared MLDH@MXene heterostructure membranes successfully break the persistent trade-off between high permeability and selectivity while mitigating the common drawbacks in 2D MXene-based lamellar membranes, e.g., swelling issues, restacking problems, and vulnerable chemical stability. Noticeably, at an operating pressure of 4 bar and a feed solution of 100 ppm of Congo red, the heterostructure membranes enable a threefold jump in permeability (332.7 +/- 20 L m(-2) h(-1 )bar(-1)) when compared to the pristine MXene membrane (119.3 +/- 18 L m(-2 )h(-1) bar(-1)), and better operational stability without compromising the rejection.

Carbon nanotubes (CNTs) have received considerable attention for their excellent thermal and electrical conductivity as well as scalable production. However, CNT dispersions are prone to settling and have a short shelf time, especially under high concentration, which significantly hinders their further processing and increases transportation costs. Here, we report a highly concentrated CNT dough enabled by ionic liquid crystal (ILC) as auxiliaries. Benefiting from the temperature-controlled physical transformation of the ILC, the CNTs of the powder state are successfully transferred to highly processable dough with excellent electrical conductivity, flame retardancy, and outstanding redispersibility even after 180 days of storage. In particular, the CNT dough exhibits excellent self-healing properties and good reshapable capability. Various bulk form CNT derived from the ILC armored CNT dough are realized by facile processing technique. Hybrid nanocomposite papers with ANF nanofiber exhibited excellent photothermal conversion and Joule heating properties. The redispersible CNT doughs presented here promise to revolutionize traditional CNT powder and dispersions as the primary raw material for building CNT-based architectures and facilitate the large-scale application of CNTs.

Noble metals are the most commonly used electrocatalysts, but due to the high-cost and scarcity, improving their utilization has become a hot topic. As the Pt-based high-entropy alloy (HEA) can greatly increase the activity of catalyst and increase the utilization of noble metal, herein, a HEA with promising performance in ethylene glycol oxidation reaction (EGOR) is developed. The EGOR results show that, the onset potential of PtPdAuNiCo/C is 0.55 V, which is 20 mV lower than Pt/C (0.57 V) reference. Besides, the PtPdAuNiCo/C exhibits a high activity of 0.482 A mg⁻¹_PtPdAu, which is 2.18 times of Pt/C (0.221 A mg⁻¹_Pt) reference. And the current retention rate of PtPdAuNiCo/C (81.3%) is also higher than Pt/C (73.0%) reference in 500-cycle stability test. When as-obtained PtPdAuNiCo/C assembled into a direct ethylene glycol fuel cell, it exhibits a high-power density of 8.38 mW cm⁻². It is 1.40 times than that of Pt/C (6.00 mW cm⁻²) reference. This work would be a good reference to HEA materials application on electrocatalysis in future.

Controlled synthesis of polymer-based porous membranes via innovative methods is of considerable interest, yet it remains a challenge. Herein, we established a general approach to fabricate porous polyelectrolyte composite membranes (PPCMs) from poly-(ionic liquid) (PIL) and MXene via an ice-assisted method. This process enabled the formation of a uniformly distributed macroporous structure within the membrane. The unique characteristics of the as-produced composite membranes display significant light-to-heat conversion and excellent performance for solar-driven water vapor generation. This facile synthetic strategy breaks new ground for developing composite porous membranes as high-performance solar steam generators for clean water production.