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High-entropy alloys have received considerable attention in the field of catalysis due to their exceptional properties. However, few studies hitherto focus on the origin of their outstanding performance and the accurate identification of active centers. Herein, we report a conceptual and experimental approach to overcome the limitations of single-element catalysts by designing a FeCoNiXRu (X: Cu, Cr, and Mn) High-entropy alloys system with various active sites that have different adsorption capacities for multiple intermediates. The electronegativity differences between mixed elements in HEA induce significant charge redistribution and create highly active Co and Ru sites with optimized energy barriers for simultaneously stabilizing OH * and H * intermediates, which greatly enhances the efficiency of water dissociation in alkaline conditions. This work provides an in-depth understanding of the interactions between specific active sites and intermediates, which opens up a fascinating direction for breaking scaling relation issues for multistep reactions. High-entropy alloy catalysts are an emerging class of materials and identification of catalytically active sites is critical. Here, we provide evidence that metal site electronegativity differences stabilize bound *OH and *H intermediates.

Carbon fiber (CF) is widely used in the preparation of carbon-fiber-reinforced polymer composites (CFRP) in which it is combined with epoxy resin due to its good mechanical properties. Thermosetting bisphenol A epoxy resin, as one of the most common polymer materials, is a non-renewable resource, leading to a heavy environmental burden and resource waste. To solve the above problems and achieve high mechanical and thermal properties comparable to those of bisphenol A, herein, a high-performance, degradable and recyclable bio-based epoxy resin was developed by reacting the lignin derivative vanillin with 4-amino cyclohexanol via Schiff base. This bio-based epoxy resin showed a Young’s modulus of 2.68 GPa and tensile strength of 44 MPa, 36.8% and 15.8% higher than those of bisphenol A epoxy, respectively. Based on the reversible exchange reaction of the imine bond, the resin exhibited good degradation in an acidic environment and was recoverable by heat treatment. Moreover, the prepared epoxy resin could be used to prepare carbon fiber (CF)-reinforced composites. By washing off the epoxy resin, the carbon fiber could be completely recycled. The recovered carbon fiber was well preserved and could be used again for the preparation of composite materials to realize the complete recovery and utilization of carbon fiber. This study opens a way for the preparation of high-performance epoxy resin and the effective recycling of carbon fiber.

Manufacturing hybrid electrodes with the combination of electroactive materials and carbon carriers brings hope for high-performance supercapacitors, but the poor interfacial compatibility between hydrophobic carbon substrate surface and active materials is still the bottleneck to be solved. Here, we propose a superhydrophilic strategy to stabilize NiCo 2 S 4 on inert carbon cloth (CC) using nitrogen-doped (N-doped) carbon layer as structure/interface coupling bridge, so as to prepare hybrid material (expressed as NiCo 2 S 4 /CC-CN) for supercapacitor. The N-doped carbon layer on CC leads to the formation of superhydrophilic surface/interface, which is conducive to the uniform growth of NiCo 2 S 4 on CC and helps to effectively strong coupling interaction between CC and NiCo 2 S 4 . In addition, the asymmetric supercapacitor made of NiCo 2 S 4 /CC-CN as the positive electrode and as-prepared activated carbon cloth (PACC) as the negative electrode provides a high energy density of 0.11 mWh cm −2 at a power density of 0.35 mW cm −2 . The interfacial engineering in this study holds the potential of creating high energy density electrodes for advanced energy storage.

Inspired by mussels, a new cellulose-based (CTP) adhesive was fabricated by simply blending via cellulose nanofibrils (CNFs), tannic acid (TA), and polyethyleneimine (PEI), where the preparation method was green, facile, and simple. The structure and properties were examined by FT-IR, TGA, XRD, SEM, lap shear tensile, and water absorption tests. The results showed that chemical bonds, hydrogen bonds, and chain entanglement were formed among CNFs, TA, and PEI. Compared with the CNF adhesive, the dry shear strength of the CTP adhesive increased 103% to 392.2 ± 32.2 kPa. And the wet shear strength of CTP adhesive increased from 0 kPa to 144.7 ± 20.1 kPa, indicating that the CTP adhesive can be used in humid or even water environments. Meanwhile, the water absorption of CTP adhesive decreased from 37.9 ± 14.1% to 12.8 ± 5.9%. It was the introduction of catechol groups and physical–chemical interactions of three components that endow the CTP adhesive with improved dry and wet adhesion strength and water resistance. Moreover, the proposed CTP adhesive could be used on the surface of various materials, including rubber, plastic, paper, wood, metal, and glass. Overall, this work shows that the CTP adhesive has a wide range of application prospects. Graphical abstract

Clusteroluminescence (CL) has recently gained significant attention due to its unique through‐space interactions associated with a high dependence on the aggregation of subgroups. These distinct features could easily transform the stimuli into visual fluorescence and monitor the fluctuation of the environment but have not received sufficient attention before. In this work, supramolecular films are designed based on the neutralization reaction of anhydride groups and the self‐assembly of dynamic covalent disulfide bonds in NaOH aqueous solution. The self‐assembly of hydrophilic carboxylate chromophores and hydrophobic disulfide‐containing five‐membered rings could be observed by the variation of the aggregation state of carboxylate in CL. Furthermore, the dynamic cross‐linking films obtained with water‐sensitive carboxylate chromophores could alter the aggregation distance stimulated by surrounding water vapor, causing the emission wavelength to change from 534 to 508 nm by varying the relative humidity. This work not only provides an approach to monitor the self‐assembly of clusteroluminogens but also offers new strategies for designing stimuli‐responsive materials that utilize the intrinsic features of CL.

Thermosetting resins play an increasingly important role in daily life due to their good mechanical properties. However, they can hardly be recycled and reused, leading to severe environmental pollution. A very promising solution to this dilemma is to develop sustainable thermosets from biomass that can be recycled and reprocessed on demand under environmentally friendly conditions. In this study, sustainable thermosets based on dynamic acylhydrazone bonds made from biomass acid derivatives is reported. The sustainability of the presented acylhydrazone biomass covalent adaptable networks (CANs) thermosetting resins is summarized as follows: 1) The raw materials are renewable resources; 2) the resins can be recycled to maintain their mechanical properties, which can considerably extend their service life; and 3) the material preparation and recycling can be conducted in the mixed solvent of water/ dimethyl sulfoxide (7/3), which excellent reduced the use of organic solvents. In addition, these acylhydrazone CANs thermosets have excellent mechanical performance and outstanding heat resistance. The acylhydrazone bonds in the thermoset networks can enhance the hydrophobicity and water resistance of the acylhydrazone CANs thermosets. Taken together, these acylhydrazone CANs thermosets which are fabricated and recycled in the mixed solvent provide a solution to developing sustainable materials. This rendered scheme illustrates that CANs thermosets with high glass transition temperatures (Tg) are prepared and recycled in the mixed solvent. Acylhydrazone CANs thermosets have good water resistance and can be repaired by water. The water resistance and Tg of Acylhydrazone CANs thermosets can be enhanced by dynamic acylhydrazone bonds.

MXene is widely used in the electromagnetic interference (EMI) shielding field. However, the high electromagnetic reflectivity of pure MXene causes potential secondary EMI pollution. This study presents a hollow egg‐box structure used in MXene composite film, by which the reflectivity (R) could decrease from 0.98 to 0.54 and absorbance (A) increased from 0.02 to 0.45, effectively decreasing the high electromagnetic reflectivity of pure MXene. Additionally, compared to pure MXene films, the MXene composite films exhibit improved electromagnetic interference shielding effectiveness (EMI SE) and SSE/t. The prepared films achieve a peak EMI SE of 69.19 dB at 12.4 GHz, which is 1.3 times higher than pure MXene, and a peak SSE/t of 27 888 dB cm2 g⁻¹ at 12.4 GHz, 1.4 times that of pure MXene. The hollow egg‐box structure not only enhances the electromagnetic shielding performance beyond pure MXene but also demonstrates outstanding performance compared to most reported MXene films, balancing lightweight material properties with effective shielding. Furthermore, the prepared MXene composite films with the hollow egg‐box structure show improved water resistance. Therefore, MXene composite films with hollow egg‐box structures are promising candidates for advanced EMI devices in future lightweight materials. This study presents a hollow egg‐box structure used in MXene composite films that could decrease the high electromagnetic wave reflectivity. The prepared films not only show improved electromagnetic interference shielding effectiveness and SSE/t than pure Mxene and most of MXene composite materials, but also show lightweight property and improve water resistance, highlighting their potential for advanced EMI devices in future lightweight materials.

Organic filters in traditional sunscreens usually are limited photodegradation and easily penetrate the stratum corneum and epidermal layer, leading to potential harmful effects. Melanin is a natural ubiquitous pigment that protects living organisms from intense sunlight. Inspired by the structure and function of the mussel adhesive protein, a facile strategy involving oxidative polymerization of dopamine was proposed for surface modification of titanium dioxide (TiO2) to obtain melanin/TiO2 nanoparticles. The thickness of melanin layers was varied from 1 to 7 nm by changing pH and dopamine concentration. The melanin/TiO2 nanoparticles with 1-nm-thick melanin layers showed highly efficient UV-shielding ability due to synergistic effect of melanin and TiO2. The melanin/TiO2 nanoparticles were introduced as the sole active ingredient to formulating sunscreen; sun protection factor (SPF) could reach 116.9 and 162.4 with a loading of 10 wt% and 15 wt%, respectively. Most importantly, melanin exhibits a good bioadhesion property and can effectively prevent the penetration of melanin/TiO2 nanoparticles. Thus, the as-prepared nanoparticles possess excellent UV-shielding capacity and biocompatibility, ensuring their superior performance and safe use in the sunscreen.Inspired by the structure and function of the mussel adhesive protein, a facile strategy involving oxidative polymerization of dopamine was proposed for surface modification of titanium dioxide (TiO2) to obtain melanin/TiO2 nanoparticles. The melanin/TiO2 nanoparticles with 1-nm-thick melanin layers showed highly efficient UV-shielding ability due to synergistic effect of melanin and TiO2. Most importantly, melanin exhibits a good bioadhesion property and can effectively prevent the penetration of melanin/TiO2 nanoparticles. Thus, the as-prepared nanoparticles possess excellent UV-shielding capacity and biocompatibility, ensuring their superior performance and safe use in the sunscreen.

Poly(lactide), PLA, as one of the most promising biopolymers, has been receiving increasing attention in recent years because of its excellent performances in renewability, mechanical properties, biocompatibility and biodegradability. However, its application is limited by its brittleness and low heat distortion temperatures (HDT). The low HDT mainly results from a low crystallization rate and lack of crystallinity after fast processing, e.g. injection molding. Consequently, considerable attention was paid, in recent years, to achieve fast(er) crystallization of PLA. In here, we briefly review the research progress in the crystallization modification of PLA notably by means of adding nucleating agents and stereocomplexation.

Negatively thermo-responsive 2D membranes, which mimic the stomatal opening/closing of plants, have drawn substantial interest for tunable molecular separation processes. However, these membranes are still restricted significantly on account of low water permeability and poor dynamic tunability of 2D nanochannels under temperature stimulation. Here, we present a biomimetic negatively thermo-responsive MXene membrane by covalently grafting poly (N-isopropylacrylamide) (PNIPAm) onto MXene nanosheets. The uniformly grafted PNIPAm polymer chains can enlarge the interlayer spacings for increasing water permeability while also allowing more tunability of 2D nanochannels for enhancing the capability of gradually separating multiple molecules of different sizes. As expected, the constructed membrane exhibits ultrahigh water permeance of 95.6 L m−2 h−1 bar−1 at 25 °C, which is eight-fold higher than the state-of-the-art negatively thermo-responsive 2D membranes. Moreover, the highly temperature-tunable 2D nanochannels enable the constructed membrane to perform excellent graded molecular sieving for dye- and antibiotic-based ternary mixtures. This strategy provides new perspectives in engineering smart 2D membrane and expands the scope of temperature-responsive membranes, showing promising applications in micro/nanofluidics and molecular separation. [Display omitted] •A biomimetic negatively thermo-responsive 2D membrane has dynamic tunability of 2D nanochannels under temperature stimulation.•The membrane exhibits ultrahigh water permeance of 95.6 L m−2 h−1 bar−1 at 25 °C.•The membrane shows excellent grade molecular sieving for dye- and antibiotic-based ternary mixtures.