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[Display omitted] Self-supporting tree skeleton and densely stackable phenolic resin are cleverly coupled together by a "rebar-concrete" structure. The thick electrode as a master of space utilization has extremely high areal and volumetric energy density. This work confirms the effective coupling of the self-supporting skeleton and powder materials, providing novel ideas for the preparation of thick electrodes with high mass loading. • A "rebar-concrete" structure is proposed to facilitate the high space utilization of thick electrodes. • The areal capacitance of the thick electrode reaches an astonishing 11F cm−2. • The assembled SSC device delivers competitive areal energy density of 0.63 mWh cm−2. The thick electrode design with high packing density of active materials can increase the capacity in a limited space. However, the key challenge is still to develop a system with high space utilization and ensure electron/ion transport in thick electrode. This work proposes an interesting "rebar-concrete" structure, which successfully prepared wood/phenolic resin-derived thick electrode with high space utilization by in-situ polymerization of phenolic resin (concrete) in the wood (rebar) channel. The electrode exhibits an excellent three-dimensional interconnected hierarchical pore structure due to the uniform activation of in-situ anchored KOH particles. The mass loading (35 mg cm−2) and areal capacitance (11F cm−2) of the obtained composite electrode are increased to 446 % and 1257 % of the original balsa wood, respectively. The assembled symmetric supercapacitor (SSC) exhibits a high energy density of 0.63 mWh cm−2 (3.91 mWh cm−3) and an excellent cycle stability (95 % retention after 50 000 cycles), showing good practicability in lighting LEDs or driving a fan. This strategy achieves effective coupling of self-supporting skeleton and powder materials, providing more insights and possibilities for the preparation of high energy density thick electrodes. [ABSTRACT FROM AUTHOR]

Flax fibers, with abundant resources and a low cost, are an excellent precursor of carbon fibers for supercapacitors. At present, they are very attractive for designing electrodes with high electrochemical performance via a simple and green way. Hence, we systemically control the specific surface area and pore structure of flax-based carbon fibers by impregnating them with zinc chloride (ZnCl2) solution. The results show that the dehydration and expansion effects of ZnCl2 affect the microstructure, which is directly related to the specific capacitance. After activation, the optimized electrode exhibited the highest specific capacitance of 105 F g−1 at a current density of 1 A g−1, which has been improved by more than 10 times compared to that of pure-flax based carbon fibers. Moreover, they also show an excellent cycling stability of 98.7% after 10 000 cycles, even at a high current density of 10 A g−1. These results further demonstrate that flax-based electrodes have potential to be applied to some relevant energy storage applications in the future. [ABSTRACT FROM AUTHOR]

Achieving a simple and mild preparation method to obtain high performance carbon-based flax fiber electrode for supercapacitor has become particularly important but still challenges. Hence, the excellent electrochemical performance of electrode was constructed by impregnation-heat treatment with ethylenediamine tetraacetic acid disodium zinc (EDTANa 2 Zn) and zinc nitrate (ZnNO 3) as activators. The results show that the decomposed zinc oxide (ZnO) of EDTANa 2 Zn leads to the prominently hierarchical porous structure and abundant nitrogen-doping, which provides more active storage sites for electrolyte. Likewise, the as-prepared electrode by EDTANa 2 Zn treatment exhibits the specific capacitance of 292 F g−1 at the current density of 0.5 A g−1, and keeps up with the capacitance retention of 102 % even after a 10, 000 long-cycles at the high current density of 10 A g−1. Significantly, the suitable zinc salt assisted preparation of high performance flax fiber carbon-based electrode provides a novel idea for future electrochemical energy storage. [Display omitted] • The obtained electrode was constructed by EDTANa 2 Zn and zinc nitrate. • The 950-EA electrode exhibits the specific capacitance of 292 F g−1–0.5 A g−1 • The 950-EA electrode keeps up with the capacitance retention of 102 % after 10,000 cycles. [ABSTRACT FROM AUTHOR]

The heavy metal copper is a serious hazard to human health and the environment. It is challenging to develop a highly efficient adsorbent that is easy to prepare, low cost, having large adsorption capacity, and non-polluting to the environment. Herein, an aminated electrospun polyacrylonitrile (PAN) staple fiber was prepared by grafting diethylenetriamine (DETA) after a hydrothermal reaction. DETA possessed numerous amino functional groups, thus providing more adsorption sites and higher adsorption capacity for copper ions (Cu2+). The Cu2+ adsorption behavior of the aminated fiber conformed to the pseudo-second-order kinetic model. It not only possessed high adsorption activity in the pH range of 3.0–6.0 and could reach a high saturated adsorption capacity of 349.65 mg g−1 at high Cu2+ concentrations but also had the ability to reduce the concentration below 1 mg L−1 at low Cu2+ concentrations with a small amount of adsorbent (0.5 mg). After 5 adsorption–desorption experiments, the removal efficiency of Cu2+ was maintained at more than 90%. This aminated PAN fiber is expected to become a candidate material for dealing with Cu2+ pollution. [ABSTRACT FROM AUTHOR]

In recent years, single‐atom catalysts (SACs) have become the most active part of the catalytic field due to their excellent catalytic activity. Among them, Ru SACs exhibit excellent performance in many catalytic applications due to their high atomic utilization efficiency, catalytic activity and selectivity, and relatively low cost. In order to understand the structure–performance relationship and potential catalytic mechanism of Ru SACs, this review summarizes the research progress of Ru SACs in the fields of electrocatalytic water splitting, fuel cells, nitrogen reduction, and nitrate reduction in recent years. The catalytic process of Ru single atom in different synthesis methods and modification strategies is summarized. Finally, some opportunities and challenges for the future development of Ru SACs are prospected. [ABSTRACT FROM AUTHOR]

Conductive hydrogels have emerged as excellent candidate materials for designing and fabricating flexible wearable sensors. However, there are still critical challenges in preparing high-performance, strongly adhesive, and biocompatible hydrogels through robust and green strategies. A central issue is the lack of an efficient, environmentally friendly and adaptable catalytic system for hydrogel construction. Herein, a series of natural polyphenol/Fe3+ nanodots (PPL/Fe3+ NDs) has been developed as nanoreactors to catalyze the self-gelation of vinyl monomers. The NDs could provide confined spaces for electron transfer, achieving an exceptionally high catalytic efficiency. Remarkably, they were effective in promoting the polymerization of vinyl monomers to form hydrogels even at the Fe content as low as 0.13 μg mL−1. The resulting hydrogels exhibited outstanding mechanical properties, excellent adhesive capacity, stable ultraviolet (UV)-shielding ability, and feasible electrical conductivity. These advantages allow the hydrogel as a flexible wearable sensor to monitor various human motions. It is believed that these natural polyphenolic NDs could open up new possibilities for the advancement of conductive hydrogels and contribute to the design and implementation of human–machine interaction devices. [ABSTRACT FROM AUTHOR]

Recently, there has been a growing demand for ultra‐thin carbonized wood films (CWF) with high shielding efficiency (SE) to replace non‐renewable alternatives. Researchers aim to enhance electromagnetic (EM) wave absorption and improve electromagnetic interference (EMI) SE in CWF materials to reduce secondary pollution from reflected EM waves. In this work, the carbonized wood composite film (CWF/EP/Co) with a thickness of 120 µm through the process of hot‐pressing and carbonizing wood soaked in a mixed solution of water‐borne epoxy (EP) and Co/Zn‐MOF (ZIF‐67/8) is obtained. The CWF/EP/Co film exhibits excellent conductivity (105 S cm−1) and demonstrates an excellent EMI SE (73 dB) at a 200 µm thickness. Remarkably, the specific EMI shielding effectiveness (SSE/t) of CWF/EP/Co films reached 15833.3 dB·cm2·g−1 in the X‐band, making it the highest reported value among all wood‐derived EMI shielding materials. CWF/EP/Co films have a high absorption coefficient (A) of 0.4, indicating their effectiveness in absorbing EM waves. Furthermore, the EMI shielding effect of the large‐scale wallpaper (170 mm×170 mm) is confirmed by finite element analysis. Additionally, the CWF/EP/Co film exhibits good mechanical properties and effective Joule heating performance. This shielding film shows promise in applications such as buildings and smart homes, providing EMI shielding and warming effects. [ABSTRACT FROM AUTHOR]

Due to the rapid development of intelligent technology and the pursuit of green environmental protection, responsive materials with single response and actuation can no longer meet the requirements of modern technology for intelligence, diversification, and environmental friendliness. Therefore, intelligent responsive materials have received much attention. In recent years, with the development of new materials and technologies, cellulose materials have become increasingly used as responsive materials due to their advantages of sustainability and renewability. This review summarizes the relevant research on cellulose-based intelligent responsive materials in recent years. According to the stimuli responses, they are divided into temperature-, light-, electrical-, magnetic-, and humidity-responsive types. The response mechanism, application status, and development trend of cellulose-based intelligent responsive materials are summarized. Finally, the future perspectives on the preparation and applications of cellulose-based intelligent responsive materials are presented for future research directions. [ABSTRACT FROM AUTHOR]

The shortage of freshwater resources has become a major obstacle threatening human development, and directly utilizing solar energy by solar evaporators is emerging as a promising method to produce freshwater from the seawater. Compared to many synthetic polymer‐based evaporators, cellulose‐based evaporators are expected to offer more interesting features benefiting from the renewable feature and abundant reserves of cellulose‐contained naturally occurring materials. First, according to the different fabrication methods, cellulose‐based solar evaporators can be divided into two types, i.e., top‐down utilization (wood‐based) and bottom‐up assembled (cellulose composite‐based), respectively. The different fabrication schemes also bring their own unique advantages, such as the bimodal porous structure of wood‐based evaporators and the artificial interconnection microporous network of cellulose composite‐based evaporators. Subsequently, this review further summarizes the most recent advances and highlights of those cellulose‐based solar evaporators, by focusing on their structural regulation strategies (e.g., drilled channel array, asymmetric wettability structure, delignification, 2D waterway, etc.) and evaporation performance improvements (e.g., salt resistance, high evaporation rate, etc.). Finally, the challenges in this field and potential solutions are also discussed, which are anticipated to provide new opportunities toward the future development of cellulose and other kinds of biomass‐based evaporators. [ABSTRACT FROM AUTHOR]

Compared with traditional metal materials, carbon-based materials have the advantages of low density, high conductivity, good chemical stability, etc., and can be used as reliable alternative materials in various fields. Among them, the carbon fiber conductive network constructed by electrospinning technology has the advantages of high porosity, high specific surface area and rich heterogeneous interface. In order to further improve the conductivity and mechanical properties of pure carbon fiber films, tantalum carbide (TaC) nanoparticles were selected as conductive fillers. The crystallization degree, electrical and mechanical properties of electrospun TaC/C nanofibers at different temperatures were investigated. As the carbonization temperature increases, the crystallization degree and electrical conductivity of the sample also increases, while the growth trend of electrical conductivity is markedly slowed. The best mechanical properties of 12.39 MPa was achieved when the carbonization temperature was 1200 °C. Finally, through comprehensive analysis and comparison, it can be concluded that a carbonization temperature of 1200 °C is the optimum. [ABSTRACT FROM AUTHOR]

Polyelectrolyte has wide applications in biomedicine, agriculture and soft robotics. However, it is among one of the least understood physical systems because of the complex interplay of electrostatics and polymer nature. In this review, a comprehensive description is presented on experimental and theoretical studies of the activity coefficient, one of the most important thermodynamic properties of polyelectrolyte. Experimental methods to measure the activity coefficient were introduced, including direct potentiometric measurement and indirect methods such as isopiestic measurement and solubility measurement. Next, progress on the various theoretical approaches was presented, ranging from analytical, empirical and simulation methods. Finally, challenges for future development are proposed on this field. [ABSTRACT FROM AUTHOR]

[Display omitted] The interfacial solar desalination has been considered a promising method to address the worldwide water crisis without sophisticated infrastructures and additional energy consumption. Although various advanced solar evaporators have been developed, their practical applications are still restricted by the unsustainable materials and the difficulty of precise customization for structure to escort high solar-thermal efficiency. To address these issues, we employed two kinds of naturally occurring molecules, tannic acid and iron (III), to construct a low-cost, highly efficient and durable interfacial solar evaporator by three-dimensional (3D) printing. Based on a rational structural design, a robust and 3D-printed evaporator with conical array surface structure was developed, which could promote the light harvesting capacity significantly via the multiple reflections and anti-reflection effects on the surface. By optimizing the height of the conical arrays, the 3D-printed evaporator with tall-cone structure could achieve a high evaporation rate of 1.96 kg m–2 h−1 under one sun illumination, with a photothermal conversion efficiency of 94.4%. Moreover, this evaporator was also proved to possess excellent desalination performance, recycle stability, anti-salt property, underwater oil resistance, as well as adsorption capacity of organic dye contaminants for multipurpose water purification applications. It was believed that this study could provide a new strategy to fabricate low-cost, structural regulated solar evaporators for alleviating the dilemma of global water scarcity using abundant naturally occurring building blocks. [ABSTRACT FROM AUTHOR]

Size regulation of polydopamine nanoparticles (PDA NPs) is vital to melanin‐inspired materials. The general strategy usually focuses on tuning of the reaction parameters which could affect the dopamine (DA) monomer polymerization process, such as pH, temperature, monomer concentration, etc. The reaction between boronic acids and catechols to form boronic esters has been widely applied in many fields, but little attention has been paid in the size regulation of PDA NPs. Here, it is speculated that the fine size regulation of PDA NPs can be directly achieved by using boronic acids and Lewis base molecules. It is found that these issues could indeed significantly affect the stability of the boronic esters formed by boronic acids and DA, which may further inhibit the monomer polymerization kinetics and tune the particle size of the resulting PDA NPs. It is also found that the several intrinsic properties of PDA NPs such as the free radical scavenging ability, UV spectral absorption, photothermal behavior, and structural color all change with the particle size. It is believed that this work can provide new opportunities for fabricating melanin‐inspired PDA NPs with well controlled size and properties. [ABSTRACT FROM AUTHOR]

Heavy metal ions in industrial sewage constitute a serious threat to human health. Nanocellulose-based adsorbents are emerging as an environmentally friendly material platform for heavy metal ion removal based on their unique properties, which include high specific surface area, excellent mechanical properties, and biocompatibility. In this review, we cover the most recent works on nanocellulose-based adsorbents for heavy metal ion removal and present an in-depth discussion of the modification technologies for nanocellulose in the process of assembling high-performance heavy ion adsorbents. By introducing functional groups, such as amino, carboxyl, aldehyde, and thiol, the assembled nanocellulose-based adsorbents both remove single heavy metal ions and can selectively adsorb multiple heavy ions in water. Finally, the remaining challenges of nanocellulose-based adsorbents are pointed out. We anticipate that this review will provide indispensable guidance on the application of nanocellulose-based adsorbents for the removal of heavy metal ions. [ABSTRACT FROM AUTHOR]

Stimulus-responsive hydrogels are an important member of smart materials owing to their reversibility, soft/wet properties, and biocompatibility, which have a wide range of applications in the field of intelligent actuations. However, poor mechanical property and complicated fabrication process limit their further applications. Herein, we report a light-responsive tissue paper/hydrogel composite actuator which was developed by combining inkjet-printed tissue paper with poly(N-isopropylacrylamide) (PNIPAM) hydrogel through simple in situ polymerization. Due to the high strength of natural tissue paper and the strong interaction within the interface of the bilayer structure, the mechanical property of the composite actuator was highly enhanced, reaching 1.2 MPa of tensile strength. Furthermore, the light-responsive actuation of remote manipulation can be achieved because of the stamping graphite with high efficiency of photothermal conversion. Most importantly, we also made a few remotely controlled biomimetic actuating devices based on the near-infrared (NIR) light response of this composite actuator. This work provides a simple strategy for the construction of biomimetic anisotropic actuators and will inspire the exploration of new intelligent materials. [ABSTRACT FROM AUTHOR]

In this study, ZnO nanoparticles were prepared by a hydrothermal method with varying the reaction times, material ratios and reaction temperatures. The samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray Diffraction (XRD) and Fourier infrared spectroscopy (FTIR). It was shown that the material ratio significantly affected the structure and morphology of the synthesized ZnO nanoparticles, and then the uneven nano-octahedral structure, uniform nano-octahedral structure, nano-tubular structure, and nano-sheet structure could be obtained successively. The synthesized ZnO nanoparticles as mordant were used for the dyeing of silk fabrics with different natural dyes (tea polyphenols and hematoxylin). Moreover, they could improve the dyeing properties and fastness (wash and light) on silk fabrics to a certain extent. [ABSTRACT FROM AUTHOR]

As a convenient photothermal material, polydopamine (PDA) has been widely utilized in wood-based evaporators. However, the loading conditions of polydopamine on biomass bulk materials have not been systematically studied. In this paper, the suitable reaction conditions of polydopamine were studied with rattan as the substrate, and a reference for the improvement of the loading conditions was proposed. The polydopamine-loaded rattan-based evaporator (PDA-R) prepared on this basis exhibits excellent working stability due to the unique large-scale hierarchical porous structure of rattan. In addition to excellent salt resistance and cycle performance (evaporation rate decays by 5.1% after 30 cycles), the larger-aperture channel (200–450 μm) also brings better adaptability to salinity changes than polydopamine-loaded basswood-based evaporator (PDA-BW) (the attenuation coefficient of PDA-R is 6.2%, while the attenuation coefficient of PDA-BW is 16.3%). All of these indicate the broad prospects of polydopamine-loaded rattan-based evaporator as a multi-effect treatment scheme of brine. [Display omitted] • Loading conditions of polydopamine on biomass block material is systematic studied. • PDA-R has excellent salt resistance and cycling performance in high salinity brines. • PDA-R has great adaptability to salinity changes. • The effect of uniformly dense pore size of the substrate on salinity adaptability of evaporator is explored. [ABSTRACT FROM AUTHOR]

It is an effective way to develop basswood (Tilia americana, hardwood)-derived thick carbon electrode for high energy density supercapacitors. The wood-derived anisotropic structural carbon electrodes have different transfer kinetics of the electrolyte, which will significantly affect the electrochemical performance especially at high current density. Therefore, the relationship between the sectional wood-derived electrodes and the electrochemical performance of supercapacitors were systematically studied. The results show that the high specific surface area (542 m2 g−1) of cross-sectional wood-derived carbon contributes to the excellent electrochemical performance (specific/area capacitance ~ 3040 mF cm−2/118 F g−1 at 1 mA cm−2, cycle stability ~ 82.2% after 10,000 cycles at 50 mA cm−2, and capacitive contribution of 76.64% at 5 mV s−1), which is attributed to the hierarchical porous structure and easily allows electrolytes to enter the interior even at high current density. This work provides a fundamental understanding of the dynamic behaviors of electrolyte at different wood sections, and it is expected to be extended to other wood species and wood-like structures for energy storage applications. [ABSTRACT FROM AUTHOR]

Constructing lightweight and porous adsorbents which can effectively remove dye contaminants is of great significance in the field of the sewage treatment. In this work, anisotropic cellulose nanofibril (CNF) composite sponges assisted by rectorites are fabricated through directional freeze-drying. The resulted composite sponge exhibits the superior saturated adsorption capacity and removal efficiency of 120.0 mg/g and 96.1% for methylene blue (MB), respectively, which is better than the pure CNF sponge and rectorite powders. This is attributed to the strong electrostatic interaction between CNFs and MB, and good cation exchange property of rectorites inside the three-dimensional (3D) highly porous composite sponge. The MB adsorption process of the composite sponge fits to the pseudo-second-order kinetic model and the Langmuir isotherm model well, which is affected by both boundary layer and intraparticle diffusion, resulting in a theoretical maximum adsorption capacity of 214.6 mg/g. Moreover, it also possesses a selective adsorption capacity for anionic and cationic dyes, which is expected to realize the separation treatment of different dyes according to actual application requirements. [Display omitted] • Anisotropic CNF/rectorite composite sponge by directional freeze-drying. • Superior MB adsorption capacity and removal rate of 120.0 mg/g and 96.1%. • Selective adsorption and separation capacity for anionic and cationic dyes. • Detailed evaluation of the adsorption behavior and mechanism. [ABSTRACT FROM AUTHOR]

Chain-spherical V 2 O 5 /C composites were prepared by using dandelion fibers as bio-templates through a simple vacuum-assisted immersion method, and their microstructure and electromagnetic wave (EMW) absorption properties were investigated. Results indicated that the EMW absorption performance of dandelion fibers is effectively improved by introducing V 2 O 5 and constructing chain-spherical structure. Notably, the minimum reflection loss (RL min) of V 2 O 5 /C composites with a thickness of 2.35 mm is reached −34.05 dB at 17.52 GHz, and the maximum effective absorption bandwidth (EAB) of the composites is up to 7.52 GHz at 2.85 mm. The improvement in EMW absorption performance is mainly ascribed to the synergistic effects of the increased multiple reflections and scattering, enhanced polarization loss and conduction loss, and impedance matching characteristics. The chain-spherical V 2 O 5 /C composites exhibit great potential as promising candidates for high-performance EMW absorbers. • The V 2 O 5 /C composites with a chain-spherical structure are facilely prepared. • The synergy effect of multiple loss mechanisms enhances microwave absorption. • The RL min of −34.05 dB and the widest EAB of 7.52 GHz are achieved. [ABSTRACT FROM AUTHOR]

The development of robust and bioinspired adhesives with excellent performances including fast gel time, low cost, good adhesion strength and stability, and excellent solvent and temperature resistance against harsh environment is urgent for practical applications. In this paper, kinds of natural polyphenolic adhesives have been successfully fabricated via the multiple polyphenol-diisocyanate cross-linking (PDC) reactions between natural polyphenols (extracts) and diisocyanate molecules. Under heating, as-prepared adhesives could effectively adhere onto a wide range of substrates (i.e. PTFE, PET, PMMA, Al, Cu, paper, glass, wood) through hierarchical interactions. Moreover, these adhesives exhibited great adhesion stability against complex solvents and low-temperature environments, whose adhesion strength could remain unchanged after soaking solvents after 30 days, which was conducive to their potential applications in industry and chemical fields, including petroleum, wood, metal, glass, plastics, and rubber adhesion. We believed that this work would provide new strategies towards the preparation of robust adhesives with excellent resistant against various solvents and low temperature for many fields by using naturally occurring building blocks. Natural polyphenolic adhesives were successfully fabricated via the multiple polyphenol-diisocyanate cross-linking (PDC) reactions between natural polyphenols (extracts) and diisocyanate molecules. Under heating, as-prepared adhesives could effectively adhere to a wide range of substrates (i.e. PTFE, PET, PMMA, Al, Cu, paper, glass, wood) through hierarchical interactions. Moreover, these adhesives exhibited great adhesion stability against complex solvents and low-temperature environments, and the adhesion strength could even remain unchanged after soaking solvents after 30 days. [Display omitted] • Natural polyphenolic adhesives were successfully fabricated. • As-prepared adhesives could effectively adhere to various substrates. • These adhesives exhibited great solvents and low-temperature resistance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two basic design strategies for 3D COFs: high valency and functionalization. • 3D COFs: building blocks, topology, linkage, and PSM strategy. • Applications in adsorption and separation, catalysis, stimulus response, conduction and energy storage. • The challenges and opportunities are proposed for future research. Covalent organic frameworks (COFs) are a class of porous crystalline organic materials. The dynamic chemistry of covalent bonding and the applications of COFs have made great progress already. Three-dimensional (3D) COFs have attracted much attention in recent years because of their more diverse spatial structures and interconnected pore properties. High valency and functionalization are two key strategies of 3D COFs design, including the development of building blocks, topology, linkage and post synthetic modification strategy. As a result, the diversity of COF spatial structures is significantly extending and various applications in energy, environment, biology and chemical catalysis are developing. In this review, we summarized the recent articles about 3D COFs in the field of framework design, function development and applications, and put forward the critical strategies and comment, the future perspectives of the field are also prospected. [ABSTRACT FROM AUTHOR]

Herein, we used a one-pot method to fabricate a novel MOF-on-MOF adsorbent, namely MOF(Zr)-on-MOF(Ce). The adsorbent demonstrated a high maximum fluoride-ions capture capacity of 164.47 mg g−1. The morphology, elemental distribution, pore size distribution, and thermal stability were studied using SEM-EDS, XRD, BET, and TGA. The influence of the temperature, solution pH, fluoride concentration, and coexisting ions was explored using intermittent experiments. The results suggested that MOF(Zr)-on-MOF(Ce) had a fast capture rate for fluoride. MOF(Zr)-on-MOF(Ce) maintained an excellent fluoride removal performance over a wide pH range with an initial fluoride concentration of 20 mg L−1. The optimal effect was obtained at a pH of 4, but a high removal efficiency of 94% was maintained even at a pH of 9. Interference experiments showed that only the PO 4 3– had an adverse inhibition influence. The field experiments demonstrated that MOF(Zr)-on-MOF(Ce) can keep the safety threshold levels of fluoride in drinking water. The Langmuir and pseudo-second order kinetic models were well fitted for the defluoridation process, demonstrating that the adsorption of fluoride ions on MOF(Zr)-on-MOF(Ce) was dominated by monolayer chemisorption. With the further characterization and kinetic thermodynamic studies indicates that the removal mechanism involves ion exchange, electrostatic interactions and complexation effect. [Display omitted] • A novel MOF(Zr)-on-MOF(Ce) adsorbent were fabricated via one-pot methods for defluorination. • The maximum adsorption capacity of MOF(Zr)-on-MOF(Ce) was 164.47 mg g–1 for F ions. • The adsorbent had an excellent defluoridation performance with a wide pH range. • The mechanisms are ion-exchange, electrostatic interaction and complexation effect. [ABSTRACT FROM AUTHOR]

La–Mn bimetal oxide nanofibers, used as an adsorbent for the defluoridation of water, were synthesized by an electrospinning and heat treatment technology. The La–Mn bimetal oxide nanofiber adsorbent with a specific surface area of 35.064 m2 g−1 displayed a good defluoridation performance. Both the adsorption kinetics and equilibrium for fluoride (F−) uptake onto La–Mn bimetal oxide nanofibers were investigated. The kinetic studies established that the adsorption attained equilibrium at about 90 min, and the PSO kinetic model was ideal for the kinetic data under 20 and 50 mg L−1. The Langmuir maximum F− uptake was computed to be 189.39 mg g−1 at 308 K and pH 3. A thermodynamic study affirmed a feasible, endothermic, spontaneous and entropy driven process of F− adsorption towards La–Mn bimetal oxide nanofibers at the studied temperature range. Except for the competitive adsorption of PO43− and F−, the presence of NO3−, CO32−, Cl− and SO42− had little effect on fluoride removal. The La–Mn bimetal oxide adsorbent exhibited a good reusability. [ABSTRACT FROM AUTHOR]

[Display omitted] • This review focuses on recent development of carbon dots/porous materials composites. • Preparation, structures, and properties of carbon dots/porous materials composites are discussed. • Challenges and future development of carbon dots/porous materials composites are described. Carbon dots (CDs), an emerging fluorescent carbon nanomaterial, have attracted great attention in recent year due to their features such as unique optical property, good biocompatibility and low cost and easy synthesis. When CDs are integrated with porous materials, it not only compensates for the shortcomings of monocomponent CDs in applications, but also produces new functionalities through synergistic interactions to extend new applications. At present, CDs have been assembled with various porous materials such as zeolites, carbonaceous porous materials, porous graphitic carbon nitride (g-C 3 N 4), mesoporous SiO 2 , porous metallic compounds and metal-organic frameworks (MOFs), which exhibit excellent performance and a wide range of applications. Therefore, recent research advances in CDs/porous materials composites should be presented to facilitate further development of the field. In this article, the preparation methods, porous structures, and properties of CDs/porous materials composites are classified and presented. Then, the applications of CDs/porous materials composites in optics, biomedicine, sensing, electrochemistry, and photocatalysis are also discussed. Finally, current challenges and future directions are briefly discussed to facilitate the next development of CDs/porous materials composites. [ABSTRACT FROM AUTHOR]

[Display omitted] • This review focuses on recent development of carbon dots/porous materials composites. • Preparation, structures, and properties of carbon dots/porous materials composites are discussed. • Challenges and future development of carbon dots/porous materials composites are described. Carbon dots (CDs), an emerging fluorescent carbon nanomaterial, have attracted great attention in recent year due to their features such as unique optical property, good biocompatibility and low cost and easy synthesis. When CDs are integrated with porous materials, it not only compensates for the shortcomings of monocomponent CDs in applications, but also produces new functionalities through synergistic interactions to extend new applications. At present, CDs have been assembled with various porous materials such as zeolites, carbonaceous porous materials, porous graphitic carbon nitride (g-C 3 N 4), mesoporous SiO 2 , porous metallic compounds and metal-organic frameworks (MOFs), which exhibit excellent performance and a wide range of applications. Therefore, recent research advances in CDs/porous materials composites should be presented to facilitate further development of the field. In this article, the preparation methods, porous structures, and properties of CDs/porous materials composites are classified and presented. Then, the applications of CDs/porous materials composites in optics, biomedicine, sensing, electrochemistry, and photocatalysis are also discussed. Finally, current challenges and future directions are briefly discussed to facilitate the next development of CDs/porous materials composites. [ABSTRACT FROM AUTHOR]

Designing energy storage devices from thick carbon electrodes with high areal/volumetric energy density via a simple and green way is very attractive but still challenging. Cellulose, as an excellent precursor for thick carbon electrodes with abundant sources and low cost, is usually activated by a chemical activator and pyrolysis route to achieve high electrochemical performance. However, there are still some problems to be addressed, such as the harsh activation conditions, easy collapse of porous structures, and the high cost. Herein, a 3D self‐supporting thick carbon electrode derived from wood‐based cellulose is proposed for high areal and volumetric energy density of supercapacitor from a mild, simple, and green enzymolysis treatment. Benefiting from the high specific surface area (1418 m2 g−1) and abundant active sites on the surface of wood‐derived hierarchically porous structures and enzymolysis‐induced micropores and mesopores, the assembled symmetry supercapacitor from the thick carbon electrode can realize the high areal/volumetric energy density of 0.21 mWh cm−2/0.99 mWh cm−3 with excellent stability of 86.58% after 15 000 long‐term cycles at 20 mA cm−2. Significantly, the simple and universal strategy to design material with high specific surface area, provides a new research idea for realizing multi‐functional application. [ABSTRACT FROM AUTHOR]

Flexible bioelectronics have attracted increasing research interests due to their wide range of potential applications in human motion detection, personal healthcare monitoring, and medical diagnosis. Recently, design and fabrication strategies integrated with mussel‐inspired polydopamine (PDA) have demonstrated many appealing properties, which meet the structural and functional requirements of high‐performance flexible bioelectronics. The inherent multiple reactive sites and hierarchical interactions within PDA can promote the total electrochemical activities, self‐healing, surface activation, and biocompatibility of the composite system. This review paper strives to provide a comprehensive overview on this emerging area, including the fabrication methodology, the structural and functional contributions of PDA on the whole composites, and various applications of PDA‐based flexible bioelectronics. The current challenges and future outlook in this field are also extensively discussed at the end. This paper aims to serve as a guideline in this emerging area and provide new inspirations toward next‐generation integrated multifunctional flexible PDA bioelectronics with a broad range of healthcare applications. [ABSTRACT FROM AUTHOR]

Nanocellulose, as a nanoscale polymer material, has garnered significant attention worldwide due to its numerous advantages including excellent biocompatibility, thermal stability, non-toxicity, large specific surface area, and good hydrophilicity. Various methods can be employed for the preparation of nanocellulose. Traditional approaches such as mechanical, chemical, and biological methods possess their own distinct characteristics and limitations. However, with the growing deterioration of our living environment, several green and environmentally friendly preparation techniques have emerged. These novel approaches adopt eco-friendly technologies or employ green reagents to achieve environmental sustainability. Simultaneously, there is a current research focus on optimizing traditional nanocellulose preparation methods while addressing their inherent drawbacks. The combination of mechanical and chemical methods compensates for the limitations associated with using either method alone. Nanocellulose is widely used in wound dressings owing to its exceptional properties, which can accelerate the wound healing process and reduce patient discomfort. In this paper, the principle, advantages and disadvantages of each preparation method of nanocellulose and the research findings in recent years are introduced Moreover, this review provides an overview of the utilization of nanocellulose in wound dressing applications. Finally, the prospective trends in its development alongside corresponding preparation techniques are discussed. [ABSTRACT FROM AUTHOR]

• A green and common method was proposed to prepare biomimetic actuators. • The PNPB actuator showed excellent multi-stimulus response and synergistic effect. • Anisotropic natural bamboo endowed the PNPB actuator programmable performance. • The PNPB actuator had application potential in complex environment. Hydrogel actuators with controllable deformation and excellent biocompatibility are widely used in soft robot, valve, drug delivery and lenses. However, the stimulation response performance of existing hydrogel actuators mostly focuses on a single active layer, which greatly affects its driving performance and service life. In this work, we integrate temperature-responsive hydrogel (Poly (N-isopropyl acrylamide), PNIPAM) and pH-responsive hydrogel (polyacrylic acid, PAAc) into one system to fabricate a dual active layer composite hydrogel actuator with high performance. Based on the PAAc hydrogels achieving contract or expand at different pH values, the obtained actuator exhibits admirable bidirectional bending characteristics. In addition, the anisotropic bamboo sheet endows the hydrogel actuator with programmable 3 D complex deformation. Benefitting from the synergy and different responsiveness between the two active layers, the hydrogel actuator not only has multiple response performance, but also greatly improves its deformation degree and response speed. More importantly, these promising properties of the actuator have broad application prospects in the development of pattern design and intelligent switch. This work proposes a promising strategy for the structural design of hydrogel actuators with excellent performance, and encourages more exploration of the application range of the actuator. [ABSTRACT FROM AUTHOR]

To ensure water safety, fluoride elimination from aqueous environment is an urgent affair. In this study, a series of La-modified ZIF-8 (denoted as La-ZIF-8) hybrids with different contents of La were fabricated via a solvothermal reaction and used for fluoride recovery from wastewater. The structure and morphology of the fabricated La-ZIF-8 hybrid were confirmed by various techniques (SEM, XRD, BET, FTIR, and XPS). The specific surface area along with the pore volume of La-ZIF-8 hybrid was 121 m2 g−1 and 0.816 cm3 g−1, respectively. The defluoridation performance of La-ZIF-8 under different conditions was assessed by static batch trials. The optimized La-ZIF-8 with a La/Zn molar ratio of 4:1 achieved the supreme defluoridation performance. The fluoride uptake was greatly enhanced from 1.85 mg g−1 for pure ZIF-8–49.5 mg g−1 for La-ZIF-8 at C 0 = 10 mg L−1. The results revealed that La-ZIF-8 had a maximal fluoride uptake of 224.72–230.95 mg g−1 at 30–50 °C, pH 4, and C 0 = 80 mg L−1. Adsorption of fluoride on La-ZIF-8 obeyed to the Langmuir isotherm (R 2 > 0.99) and pseudo-second order model (R 2 > 0.999), reflecting a single-layer chemical adsorption process. Δ H 0 (36.38 kJ mol−1) > 0, Δ S 0 (155.36 J mol−1 K−1) > 0, and Δ G 0 < 0 stated that the defluoridation by La-ZIF-8 is an endothermic nature, random state, highly feasible and spontaneous process. The co-existing of cations and anions effect inferred that Mg2+, Ca2+, SO 4 2–, Cl–, and NO 3 – only had a trivial impact on fluoride removal performance, illustrating the high selectivity for F–. The La-ZIF-8 can be deemed to be a candidate adsorbent for tackling F− pollution. [Display omitted] • La-ZIF-8 hybrids were successfully fabricated by a solvothermal method. • The optimal La-ZIF-8 hybrids possessed excellent fluoride removal efficiency. • The maximum uptake derived from Langmuir isotherm at 50 ℃ was 230.95 mg g−1. • The defluoridation by La-ZIF-8 is controlled by chemical adsorption. [ABSTRACT FROM AUTHOR]

• The morph-genetic method was innovatively used to fabricate the ABH actuator. • The ABH actuator exhibits promising comprehensive performance. • The assembled biomimetic actuators show excellent synergistic performance. • The biomimetic actuator shows potential for a variety of applications. Stimuli-responsive hydrogels are most promising for the fabrication of autonomous bio-mimetic soft actuators. However, their weak actuation forces and isotropic volume change hinder their practical utilization as versatile actuators, owing to their fragility. Herein, we used the morph-genetic method to fabricate anisotropic bamboo/poly(N-isopropylacrylamide) hydrogel (ABH) complex for use as soft actuator. First of all, the bamboo fiber structure provides an anisotropic framework for the ABH actuator to achieve precise deformational programmability. Secondly, benefiting from the ultra-high directional strength (110 MPa) of bamboo, ABH actuator exhibits sufficiently robust mechanical property, which generates a powerful actuating force. Lastly, owing to the regulation of bamboo sheet and PNIPAM hydrogel, the ABH actuator not only achieves ultra-fast response speed (825°/s of the bending speed), but also has excellent synergetic performance. We demonstrate several bio-mimetic actuating devices based on ABH actuator, inspired by the intricate motions of natural organisms, to highlight how the specific materials properties and their synergy can be systematically exploited for the rational design of soft actuators. Henceforth, it is anticipated that the development of hydrogel actuators could continue to benefit from the use of various naturally-anisotropic materials, such as shape-memory polymers or liquid crystals, for the preparation of further advanced hydrogel actuators by the morph-genetic method. [ABSTRACT FROM AUTHOR]

• PPy-coated P(NIPAM-ABP) electrospun nanofiber can provide high strength. • PPy-coating by in situ polymerization can provide high light-responsive. • The actuator owns ultrafast deformation and rapid recovery. • The actuator can realize various 3D programmable complex deformations. • We have explored new biomimetic devices based on the advantages of the actuator. Intelligent hydrogels are promising for biomimetic actuators, but acquiring actuations with both high speed and powerful force is still extremely difficult. Herein, a new robust polypyrrole (PPy)-coated copoly(isopropylacrylamide-4-benzoylphenyl acrylate) [P(NIPAM-ABP)] electrospun light-responsive hydrogel is explored. The (PPy)-coated P(NIPAM-ABP) hydrogel can be obtained via in-situ polymerization of pyrroles on the nanofiber-oriented electrospun P(NIPAM-ABP) hydrogel. Compared with original P(NIPAM-ABP) hydrogel, this PPy-coated P(NIPAM-ABP) hydrogel can integrate highly-enhanced mechanical strength (from 1.21 to 5.12 MPa of tensile strength) and ultrahigh-efficiency of photothermal conversion together. In addition, the orientation of P(NIPAM-ABP) nanofibers can still maintain well for programmable complex deformations. Consequently, the as-prepared robust bi-hydrogel actuator with ultrafast and complex deformations has been achieved, through bonding the PPy-P(NIPAM-ABP) hydrogel membrane with a polyethylene glycol diacrylate-cellulose nanofiber (PEGDA-CNF) composite hydrogel membrane via interfacial ultraviolet (UV) polymerization of PEGDA monomers. Several light-responsive biomimetic actuating devices have been achieved, which owning powerful force (can grab up 100 times of self-weight), rapid speed (1285.71°/s of folding) or precisely programmable complex deformations. Furthermore, two biomimetic devices with synergistic functions of the three advantages above have been explored, which can mimic the child's sit-up and the starfish's continuous crawling movement respectively. This work provides a robust remotely-controlled light-responsive hydrogel actuator with powerful force, ultrafast speed and programmable complex actuations, which will inspire the design and fabrication of novel soft biomimetic actuating materials and systems. [ABSTRACT FROM AUTHOR]

Electrospinning is a common method for preparing nanomaterials. Among many electrospinning materials, electrospun carbon nanofibers (CNFs) have become one of the hot research directions for advanced functional materials owing to their good mechanical properties, high surface area, excellent flexibility, physical and chemical stability. Particularly, significant progress has been made in the engineering advancement of electrospinning, electrospun CNFs and their derived reinforced composites to fulfill various applications. This review aims to afford a comprehensive overview of electrospun CNF reinforced composites. Firstly, the different precursors, the correlative properties, and surface modification strategies (e.g. , physical modification and chemical modification) of electrospun CNFs are introduced. Secondly, the preparation methods of reinforced composites based on electrospun CNFs are described in detail. Then, the functional applications of electrospun CNF reinforced composites are discussed. Finally, the challenges and future solutions of electrospun CNF reinforced composites are also prospected. This review is expected to offer a basic but deep understanding of modification strategies to heighten the surface performances of CNFs for the future development of high-performance electrospun CNF reinforced composites in the composite industry, defense, and aerospace applications. [Display omitted] • Electrospun CNF reinforced composites are widly used in engineering materials. • The precursors and modification strategies of electrospun CNFs are detailly reviewed. • Diverse preparation and application of CNF reinforced composites are summarized. • The current challenges of electrospun CNF reinforced composites are discussed. • The future prospects of CNF-based composites in advanced engineering are proposed. [ABSTRACT FROM AUTHOR]

In recent years, various biomasses (such as coconut, cotton, wheat straw, basswood, bamboo, etc.) have been utilized to prepare porous carbon materials (PCMs) through carbonization and/or physical/chemical activation. Most of these carbon materials are limited by the electric double-layer capacitance, resulting in a limited specific capacitance. Moreover, the preparation processes are often complicated and the carbon yield is low. Therefore, from the perspective of green and sustainable preparation of PCMs with high carbon yield and high performance, in this study, N-doped porous carbon electrodes were prepared by one-step activation carbonization method using camellia oleifera branches as raw material and NH 4 Cl as the activator. The N-doped NCW-2 sample has a rational hierarchical porous structure and high N doping amount (3.35 at. %) and exhibited optimal rate performance with a specific capacitance of 250 F g−1 at 50 A g−1. The symmetrical device also presented excellent performance with a capacitance retention of 93.7 % after cycling 30,000 times at 20 A g−1 and delivered superior rate performances of 22.3 W h kg−1@100 W kg−1 to 11.8 W h kg−1@4800 W kg−1. This work may provide a certain reference for the preparation of N-doped biomass-derived PCMs and widen its practical application in supercapacitor devices. [Display omitted] • The self-supporting N-doped porous carbon can be directly used without posttreatment. • The mechanism of doping and activation are preliminarily proposed. • The as-prepared material has a high nitrogen doping of 3.35 at. %. • Electrodes exhibited a high specific capacitance of 250 F g−1 even at 50 A g−1. • The symmetrical device showed a capacitance retention of 93.7 % after 30,000 cycles. [ABSTRACT FROM AUTHOR]

Near-infrared light-responsive hydrogel actuator with complex deformations and remote precise control is fabricated from the natural bamboo. The resulting biomimetic bamboo/PNIPAM hydrogel actuator can be precisely designed to perform a variety of simulations. [Display omitted] • Biomimetic actuators based on anisotropic natural bamboo were prepared. • Nigrosine was first used to fabricate light-responsive hydrogel actuator. • The actuator exhibits outstanding programmability and remote-control performance. • The actuator can move freely on the water surface based on Marangoni effect. Near-infrared light-responsive hydrogels are one of the most important soft biomimetic actuators owing to their accuracy, remote control performance, and permeability. However, the complex deformations and materials of hydrogel actuators are still a serious challenge. Herein, we have developed a novel composite hydrogel actuator by combining natural bamboo sheet and nigrosine/poly(N-isopropylacrylamide) (PNIPAM) composite hydrogel. The high-efficient photothermal conversion of the nigrosine/PNIPAM composite hydrogel sheet generates light-responsive actuation that is remotely controllable. Furthermore, the bamboo sheet with fiber-oriented structure can be cut at different angles, which facilitates programmable 3D complex deformations in the actuator. Accordingly, we have designed a series of biomimetic actuating devices, including simulations of butterfly antenna, Dendrobium , smart switch, and even a multi-step deformational biomimetic claw. In addition, we also explored a biomimetic insect with precisely-controlled fast movements on the water surface based on Marangoni effect. This work provides a simple but general strategy for fabricating biomimetic actuators and will inspire new designs for intelligent soft actuators. [ABSTRACT FROM AUTHOR]

A reusable magnetic WC-Co composite (Co/C-1000) filter with efficient water treatment was prepared by in-situ growth of ZIF-67 on the inside and outside surface of wood following by carbonization. [Display omitted] • Magnetic WC-Co composite is designed for wastewater treatment. • WC-Co composite has ultra-high dyes adsorption capacity. • The Co/C-1000 filter has good removal efficiency for high dye concentration solution at a higher flux. • The Co/C-1000 filter with excellent thermal stability can be recycled by simple burning method. Organic dye in water is a crucial global environmental problem. Notably, dyes, especially anionic dye Congo red (CR) and cationic dye Methylene blue (MB), have carcinogenic and mutagenic effects on human health. However, the commercial activated carbon with bad reusability is difficult to collect, which results in poor actual adsorption. In this paper, ZIF-67@wood obtained by in situ growth of ZIF-67 on wood is carbonized to prepare magnetic WC-Co composites. The hierarchical porous structure of wood can facilitate the rapid passage of dye solution, and promote full contact between magnetic core–shell Co/C nanoparticles and dyes. The adsorption capacities of CR and MB by Co/C-1000 are 1117.03 and 805.08 mg g−1, respectively. The pH pzc (7.9) of Co/C-1000 is then determined. When the dye concentration reaches 1200 mg L−1, the removal efficiency of Co/C-1000 reaches 99.98% under gravity. With the flux of 1.0 × 104 L m−2h−1 for CR solution (100 mg L−1), the removal efficiency of Co/C-1000 filter connected with peristaltic pump is almost 99.28%. In addition, the Co/C-1000 filter with high reusability and the adsorbed dyes can be removed by simple burning. This economical, recyclable and self-supporting filter with ultra-high adsorption capacity feature has the potential to replace commercial activated carbon and it will be widely used in practical wastewater treatment. [ABSTRACT FROM AUTHOR]

A reusable magnetic WC-Co composite (Co/C-1000) filter with efficient water treatment was prepared by in-situ growth of ZIF-67 on the inside and outside surface of wood following by carbonization. [Display omitted] • Magnetic WC-Co composite is designed for wastewater treatment. • WC-Co composite has ultra-high dyes adsorption capacity. • The Co/C-1000 filter has good removal efficiency for high dye concentration solution at a higher flux. • The Co/C-1000 filter with excellent thermal stability can be recycled by simple burning method. Organic dye in water is a crucial global environmental problem. Notably, dyes, especially anionic dye Congo red (CR) and cationic dye Methylene blue (MB), have carcinogenic and mutagenic effects on human health. However, the commercial activated carbon with bad reusability is difficult to collect, which results in poor actual adsorption. In this paper, ZIF-67@wood obtained by in situ growth of ZIF-67 on wood is carbonized to prepare magnetic WC-Co composites. The hierarchical porous structure of wood can facilitate the rapid passage of dye solution, and promote full contact between magnetic core–shell Co/C nanoparticles and dyes. The adsorption capacities of CR and MB by Co/C-1000 are 1117.03 and 805.08 mg g−1, respectively. The pH pzc (7.9) of Co/C-1000 is then determined. When the dye concentration reaches 1200 mg L−1, the removal efficiency of Co/C-1000 reaches 99.98% under gravity. With the flux of 1.0 × 104 L m−2h−1 for CR solution (100 mg L−1), the removal efficiency of Co/C-1000 filter connected with peristaltic pump is almost 99.28%. In addition, the Co/C-1000 filter with high reusability and the adsorbed dyes can be removed by simple burning. This economical, recyclable and self-supporting filter with ultra-high adsorption capacity feature has the potential to replace commercial activated carbon and it will be widely used in practical wastewater treatment. [ABSTRACT FROM AUTHOR]

Hierarchical porous carbon-based electrodes, benefiting from their facilitated ion diffusion and electron conduction, have demonstrated enormous potential in supercapacitors. The preparation of hierarchical carbons with uniformity and appropriate porosity, however, still remains a grand challenge, which hinders their widespread applications. Herein, a hierarchical porous polyimide-derived carbon electrode (CPC-Fe/Zn) has been fabricated by employing bimetallic salts (Fe/Zn) as precursor and template to activate the cellulose/polyimide (PI) carbon (CPC). Originating from suitable distribution of mesopores and micropores, the obtained CPC-Fe/Zn delivers a high specific capacitance of 420 F/g at a current density of 1 A/g. Moreover, a symmetric supercapacitor device assembled with CPC-Fe/Zn exhibits delivers an energy density of 35.5 Wh/kg at a power density of 800 W/kg. Even at a larger current density of 20 A/g, the specific capacitance retention of such device still remains 92.5 % after 10,000 cycles, showing the rate performance and stability. This work has proposed a bimetallic salts template-assisted strategy to precisely modulate of the pore structure of carbon electrodes, which provides a promising platform to design superior electrodes for various electrochemical systems. [Display omitted] • The hierarchically porous structure of the material can be modulated precisely. • The symmetric supercapacitor exhibited a remarkable energy density of 35.5 Wh/kg @ 1000 W/kg. • The specific capacitance retention of symmetric supercapacitor reached 92.5 % after 10,000 cycles. [ABSTRACT FROM AUTHOR]

[Display omitted] • The actuator can achieve synergistic movement of deformation and transportation. • Added Fe 3 O 4 NPs provide both magnetism and high-efficient photothermal conversion. • The hydrogel actuator owns high tensile-strength of 4.59 MPa via electrospinning. • The actuator can provide ultrafast deformational speed of 178°/s. • We have explored new bio-inspired systems with two/multi-step synergic actuation. As a soft/wet intelligent material, hydrogel actuators with multiple stimuli-responsiveness have been widely developed. However, it is still greatly difficult for them to integrate bi/multiple responsiveness together for bio-mimetic synergistic actuation. Here, we have explored a high-strength anisotropic bi-layer hydrogel actuator with P(NIPAM-ABP) layer and Fe 3 O 4 /PAN layer via electrospinning technique, which can provide programmable bi-functional synergistic movement. The Fe 3 O 4 /PAN layer can provide magnetic responsive navigation for long-range transportation on account of the magnetism of the Fe 3 O 4 nanoparticles. Furthermore, the ultrahigh photothermal conversion efficiency of the Fe 3 O 4 nanoparticles in the Fe 3 O 4 /PAN layer, can endow the P(NIPAM-ABP) layer with fast remotely-controlled photothermal-responsive deformation. Most importantly, this hydrogel actuator can achieve complex higher-level programmable movements than before based on the synergy of remotely-controlled deformation and the long-range transportation, which can be utilized to design various novel bio-mimetic soft-robots. Last but not least, the introduction of the electrospinning, not only can achieve high strength (4.59 MPa of tensile strength) of this bi-layer hydrogel, but also can provide both ultrafast (178°/s) and programmable complex photothermal-responsiveness, owing to the ultrahigh specific surface area (ultra-thin and porous structure) and excellent orientation of the thermal-responsive P(NIPAM-ABP) nanofibers respectively. This work will provide a general method via electrospinning for anisotropic hydrogel actuator with bi/multiple-functional synergy and will provide a new strategy for smart actuators and other bio-mimetic intelligent materials/systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • The recent progress of electrospun nanofibers as electrocatalysts for flexible metal-air batteries has been reviewed. • The fundamental principles of electrospinning technique have been introduced. • The importance of bifunctional electrocatalysts for oxygen reduction and oxygen evolution in metal-air batteries has been highlighted. • Future perspectives of novel electrospun nanofibers composite for flexible metal-air batteries have been proposed. Rechargeable metal-air (O 2) batteries have been regarded as the promising candidates for wearable and flexible energy devices owing to their outstanding energy density, low cost, and high safety. Generally, the electrocatalyst at air cathode plays a significant role in various metal-air (O 2) batteries. As a versatile and efficient technique, electrospinning has been considered as a powerful method to fabricate nanofibers, which hold great potential as bifunctional electrocatalysts for such batteries. Although great progresses have been achieved in improving the electrochemical performance of catalysts in recent years, some critical challenges still maintain. In this review, the advanced electrospun carbon nanofiber-based electrocatalysts for flexible metal-air batteries have been summarized. Then, additional discussions have been included focusing on the advantages and characteristics of different nanofibers and some special requirements for various flexible metal-air batteries. Moreover, some current challenges and future prospects in the development of electrospun carbon nanomaterials for flexible metal-air cathode catalysts have been rationally analyzed. [ABSTRACT FROM AUTHOR]

With the development of the electronic industry bringing convenience to people, a series of caused electromagnetic pollution problems (e.g., electromagnetic interference (EMI)) have recently also become urgent tasks. In this work, an anisotropic composite sponge consisting of cellulose nanofibrils (CNFs) and chemical co-precipitated silver nanowire (AgNW)@Fe 3 O 4 composites was successfully prepared. Due to the introduction of anisotropic structures and the synergistic effect among CNFs, AgNWs, and Fe 3 O 4 , this composite sponge exhibited low density (16.76 mg/cm3), good saturation magnetization (4.21 emu/g) and electrical conductivity (0.02 S/cm), and anisotropic EMI shielding ability. By adjusting the proportion (1:0.3) between AgNWs and Fe 3 O 4 and their loading (0.15 vol%) inside the sponge, the reflection loss of the sponge with the improved interface impedance mismatch was only 2.3 dB, accounting for 7.2% of the total loss. It is expected to become a promising EMI shielding material, especially for effectively alleviating the secondary reflection EM pollution. [Display omitted] [ABSTRACT FROM AUTHOR]

An alternative magnetic field (AMF)-induced electrospun fibrous thermoresponsive composite actuator showing penetrable remote-control ability with fast response is shown here for the first time. The built-in heater of magnetothermal Fe3O4 nanoparticles in the actuator and the porous structure of the fibrous layer contribute to a fast actuation with a curvature of 0.4 mm−1 in 2 s. The higher loading amount of the Fe3O4 nanoparticles and higher magnetic field strength result in a faster actuation. Interestingly, the composite actuator showed a similar actuation even when it was covered by a piece of Polytetrafluoroethylene (PTFE) film, which shows a penetrable remote-control ability. [ABSTRACT FROM AUTHOR]

Although tremendous efforts have been devoted to manganous oxide (MnO)-based hybrid electrode materials, the rational design and facile preparation of high-performance MnO hybrid supercapacitors are still full of challenges, due to the inevitable agglomeration and limited stability of MnO within carbon matrixes. In this work, we developed a direct one-pot polymerization method to synthesize a series of Mn ion doped polylevodopa [P(L- DOPA)] synthetic melanin nanoparticles (Mn@SMNPs) for further transforming into small-sized hybrid carbon nanoparticles (MnO@CNPs, 20–80 nm) consisting of many stable Mn-related chemical bindings (C–N–Mn). The obtained MnO@CNPs electrode materials with physically spatial protection and well distribution of MnO could display high specific capacitance values (e.g., 545 F g−1 at 0.5 A g−1 in 6 M KOH electrolyte) within a wide operation voltage of 1.3 V. This work will continue to provide an inspiration towards the fabrication of the next-generation of high-performance synthetic melanin-based energy storage materials and devices. [Display omitted] ● MnO@CNPs were prepared through a facile one-pot fabrication strategy with small size and high MnO doping content. ● The obtained MnO@CNPs with physically protection showed a well distribution of MnO. ● The stable C–N–Mn chemical binding structure facilitates the stabilization of MnO during the charging and discharging. [ABSTRACT FROM AUTHOR]

• A new double-network hydrogel is explored for uranium recovery from seawater. • U-adsorption capacity of the hydrogel is greatly enhanced by added nanoclay. • Mechanical property of the hydrogel is largely improved by th double-network. • Used materials are lowcost and the hydrogel owns good U-adsorption reusability. Massive uranium recovery from seawater is a key project to provide the long-time consumption of global nuclear power, while it is still greatly difficult to achieve high-efficient adsorbents with high mechanical property. In this work, a new nanoclay-poly(amidoxime) (NC-PAO) high-strength double-network (DN) composite hydrogel adsorbent with high-efficient and fast uranium extraction capacity has been explored. The uranium adsorbing performance can be significantly enhanced by the small content of added super-hydrophilic NC (Laponite RDS sheets), because of the largely improved hydrophilicity of the hydrogel. Compared with the blank PAO DN hydrogel without nanoclay, the uranium adsorbing capacity of this NC-PAO DN hydrogel can largely increase 73.4% from 4.97 mg/g to 8.62 mg/g, after in seawater only 25 days. The uranium adsorption rate of this hydrogel from natural seawater, can reached 0.345 mg/(g∙day), which is excellent among existing uranium adsorbents. Furthermore, this hydrogel has high mechanical performance with 2.42 MPa of tensile strength and 16.13 MPa of compressive strength, which can be used in seawater for relatively longer time than traditional low-strength single-network hydrogel, owing to its double network (DN) structure (the weakly crosslinked gelatin soft network and the strongly crosslinked cellulose nanofiber (CNF) hard network). This NC-PAO DN hydrogel adsorbent will be an excellent candidate for fast uranium recovery from seawater in largescale. Most importantly, this work will inspire the development of new hydrogel-based adsorbents and even other type of adsorbents for high-efficient uranium extraction, through compositing various low-cost and super-hydrophilic nanomaterials to significantly improve the hydrophilicity of the adsorbent and designing double-network structure to largely enhance the mechanical property. [ABSTRACT FROM AUTHOR]

Magnetic composites had attracted considerable attention owing to their outstanding properties in separation techniques. In this work, Fe 3 O 4 @polydopamine-g- l -cysteine (Fe 3 O 4 @PDA-g-L-Cys) core-shell composites were successfully fabricated via dopamine self-polymerization and zwitterionic cysteine covalent graft, aiming for removing Pb2+ from an aqueous solution. The structure and morphology of Fe 3 O 4 @PDA-g-L-Cys were verified by FT-IR, XRD, TEM and SEM. The factors (pH, adsorbent dosage, temperature, initial concentration, etc.) affecting the adsorption properties were systematically evaluated. Adsorption data were expressed by the Langmuir isotherm. The kinetic date of Fe 3 O 4 @PDA-g-L-Cysadsorbent for Pb2+adsorptionfitted the pseudo-second order kinetic model well. The obtained thermodynamics constantsΔ G 0, Δ H 0, and Δ S 0 indicated that process of Pb2+ removal by Fe 3 O 4 @PDA-g-L-Cys were endothermic and spontaneous. • A controllable strategy to prepare Fe 3 O 4 @PDA@L-Cys was presented for the first time. • The factors affecting the adsorption properties were systematically evaluated. • Fe 3 O 4 @PDA@L-Cys exhibited high adsorption capacity to Pb2⁺ and excellent recyclability. • The thermodynamic properties of adsorption behavior of Fe 3 O 4 @PDA@L-Cys were studied. [ABSTRACT FROM AUTHOR]