Linkage Effect Induced by Hierarchical Architecture in Magnetic MXene-based Microwave Absorber.

Hierarchical architecture engineering is desirable in integrating the physical-chemical behaviors and macroscopic properties of materials, which present great potential for developing multifunctional microwave absorption materials. However, the intrinsic mechanisms and correlation conditions among cellular units have not been revealed, which are insufficient to maximize the fusion of superior microwave absorption (MA) and derived multifunctionality. Herein, based on three models (disordered structure, porous structure, lamellar structure) of structural units, a range of MXene-aerogels with variable constructions are fabricated by a top-down ice template method. The aerogel with lamellar structure with a density of only 0.015 g cm-3 exhibits the best MA performance (minimum reflection loss: -53.87 dB, effective absorption bandwidth:6.84 GHz) at a 6 wt.% filling ratio, which is preferred over alternative aerogels with variable configurations. This work elucidates the relationship between the hierarchical architecture and the superior MA performance. Further, the MXene/CoNi Composite aerogel with lamellar structure exhibits >90% compression stretch after 1000 cycles, excellent compressive properties, and elasticity, as well as high hydrophobicity and thermal insulation properties, broadening the versatility of MXene-based aerogel applications. In short, through precise microstructure design, this work provides a conceptually novel strategy to realize the integration of electromagnetic stealth, thermal insulation, and load-bearing capability simultaneously.

Tough Hydrogels with Different Toughening Mechanisms and Applications.

Load-bearing biological tissues, such as cartilage and muscles, exhibit several crucial properties, including high elasticity, strength, and recoverability. These characteristics enable these tissues to endure significant mechanical stresses and swiftly recover after deformation, contributing to their exceptional durability and functionality. In contrast, while hydrogels are highly biocompatible and hold promise as synthetic biomaterials, their inherent network structure often limits their ability to simultaneously possess a diverse range of superior mechanical properties. As a result, the applications of hydrogels are significantly constrained. This article delves into the design mechanisms and mechanical properties of various tough hydrogels and investigates their applications in tissue engineering, flexible electronics, and other fields. The objective is to provide insights into the fabrication and application of hydrogels with combined high strength, stretchability, toughness, and fast recovery as well as their future development directions and challenges.

Chromatin architecture of two different strains of Artemisia annua reveals the alterations in interaction and gene expression.

MAIN CONCLUSION: The hierarchical architecture of chromatins affects the gene expression level of glandular secreting trichomes and the artemisinin biosynthetic pathway-related genes, consequently bringing on huge differences in the content of artemisinin and its derivatives of A. annua. The plant of traditional Chinese medicine "Qinghao" is called Artemisia annua L. in Chinese Pharmacopoeia. High content and the total amount of artemisinin is the main goal of A. annua breeding, nevertheless, the change of chromatin organization during the artemisinin synthesis process has not been discovered yet. This study intended to find the roles of chromatin structure in the production of artemisinin through bioinformatics and experimental validation. Chromosome conformation capture analysis was used to scrutinize the interactions among chromosomes and categorize various scales of chromatin during artemisinin synthesis in A. annua. To confirm the effect of the changes in chromatin structure, Hi-C and RNA-sequencing were performed on two different strains to find the correlation between chromatin structure and gene expression levels on artemisinin synthesis progress and regulation. Our results revealed that the frequency of intra-chromosomal interactions was higher in the inter-chromosomal interactions between the root and leaves on a high artemisinin production strain (HAP) compared to a low artemisinin production strain (LAP). We found that compartmental transition was connected with interactions among different chromatins. Interestingly, glandular secreting trichomes (GSTs) and the artemisinin biosynthetic pathway (ABP) related genes were enriched in the areas which have the compartmental transition, reflecting the regulation of artemisinin synthesis. Topologically associated domain boundaries were associated with various distributions of genes and expression levels. Genes associated with ABP and GST in the adjacent loop were highly expressed, suggesting that epigenetic regulation plays an important role during artemisinin synthesis and glandular secreting trichomes production process. Chromatin structure could show an important status in the mechanisms of artemisinin synthesis process in A. annua.

Computer Aided Diagnosis of Melanoma Using Deep Neural Networks and Game Theory: Application on Dermoscopic Images of Skin Lesions.

Early detection of melanoma remains a daily challenge due to the increasing number of cases and the lack of dermatologists. Thus, AI-assisted diagnosis is considered as a possible solution for this issue. Despite the great advances brought by deep learning and especially convolutional neural networks (CNNs), computer-aided diagnosis (CAD) systems are still not used in clinical practice. This may be explained by the dermatologist's fear of being misled by a false negative and the assimilation of CNNs to a "black box", making their decision process difficult to understand by a non-expert. Decision theory, especially game theory, is a potential solution as it focuses on identifying the best decision option that maximizes the decision-maker's expected utility. This study presents a new framework for automated melanoma diagnosis. Pursuing the goal of improving the performance of existing systems, our approach also attempts to bring more transparency in the decision process. The proposed framework includes a multi-class CNN and six binary CNNs assimilated to players. The players' strategies is to first cluster the pigmented lesions (melanoma, nevus, and benign keratosis), using the introduced method of evaluating the confidence of the predictions, into confidence level (confident, medium, uncertain). Then, a subset of players has the strategy to refine the diagnosis for difficult lesions with medium and uncertain prediction. We used EfficientNetB5 as the backbone of our networks and evaluated our approach on the public ISIC dataset consisting of 8917 lesions: melanoma (1113), nevi (6705) and benign keratosis (1099). The proposed framework achieved an area under the receiver operating curve (AUROC) of 0.93 for melanoma, 0.96 for nevus and 0.97 for benign keratosis. Furthermore, our approach outperformed existing methods in this task, improving the balanced accuracy (BACC) of the best compared method from 77% to 86%. These results suggest that our framework provides an effective and explainable decision-making strategy. This approach could help dermatologists in their clinical practice for patients with atypical and difficult-to-diagnose pigmented lesions. We also believe that our system could serve as a didactic tool for less experienced dermatologists.

Generating Assembled MFI Nanocrystals with Reduced b-Axis through Structure-Directing Agent Exchange Induced Recrystallization.

Controlling crystal size and shape of zeolitic materials is an effective way to promote their mass transport and catalytic properties. Herein, we report a single step, Na+ - and porogen- free crystallization of MFI hierarchical architecture made up of aligned nanocrystals with reduced b-axis thickness (5-23 nm) and adjustable Si/Al ratios between 35 to 120, employing the commonly used tetrapropylammonium hydroxide (TPAOH) and tetrabutylammonium hydroxide (TBAOH) as structure-directing agents (SDAs). Homogeneous nucleation driven by both SDAs and subsequent SDA-exchange induced dissolution-recrystallization are responsible for the formation of such structure. The enhanced textural and diffusion properties account for a notable exaggeration of propene selectivity and catalyst lifetime in dimethyl ether-to-olefins (DTO) conversion. This protocol is extendable to the rational synthesis of other hierarchical zeolites through crystallization process control.

Waste paper derived three-dimensional carbon aerogel integrated with ceria/nitrogen-doped reduced graphene oxide as freestanding anode for high performance and durable microbial fuel cells.

Despite the green energy generation with low cost compared to conventional fuel cells, microbial fuel cells (MFCs) still suffer with anode related constraints including laborious pretreatment and modification process of conventional electrodes, limited bacterial loading capacity, and inferior extracellular electron transfer efficiency. Accordingly, this investigation explores the waste tissue paper derived three dimensional (3D) carbon aerogel (CA) integrated with cerium dioxide (CeO2) nanotubes decorated nitrogen-doped reduced graphene oxide nanosheets (NRGO) as a competent anode to address these technical complements. The direct growth of NRGO and CeO2 over CA in the form of freestanding and binder-free NRGO/CeO2(1:2)/CA alleviates the significant constrains of conventional anode fabrication. The 3D hierarchical architectures of CA with open porous structure provide easy access of bacteria, thus increases the bacterial colonies per unit volume. Furthermore, the hydrogen bonding between the interfacial oxygen atoms of CeO2 and lysine residues of the cytochrome c in bacteria yields excellent extracellular electron transfer efficiency. The electrostatic interaction between the NRGO and bacteria cells improves the bacterial adhesion and biofilm formation, leading to the compact biofilm formation for the improved direct electron transference. With the profits of above, the MFC with NRGO/CeO2(1:2)/CA demonstrates a maximum power output and good lifespan performances. The present exploration facts thus access advanced avenues to converting waste matters of tissue paper, human urine, and wastewater into profitable constituents for the development of efficient and durable power producing systems.

Genome-wide Hi-C analysis reveals extensive hierarchical chromatin interactions in rice.

The non-random spatial packing of chromosomes in the nucleus plays a critical role in orchestrating gene expression and genome function. Here, we present a Hi-C analysis of the chromatin interaction patterns in rice (Oryza sativa L.) at hierarchical architectural levels. We confirm that rice chromosomes occupy their own territories with certain preferential inter-chromosomal associations. Moderate compartment delimitation and extensive TADs (Topologically Associated Domains) were determined to be associated with heterogeneous genomic compositions and epigenetic marks in the rice genome. We found subtle features including chromatin loops, gene loops, and off-/near-diagonal intensive interaction regions. Gene chromatin loops associated with H3K27me3 could be positively involved in gene expression. In addition to insulated enhancing effects for neighbor gene expression, the identified rice gene loops could bi-directionally (+/-) affect the expression of looped genes themselves. Finally, web-interleaved off-diagonal IHIs/KEEs (Interactive Heterochromatic Islands or KNOT ENGAGED ELEMENTs) could trap transposable elements (TEs) via the enrichment of silencing epigenetic marks. In parallel, the near-diagonal FIREs (Frequently Interacting Regions) could positively affect the expression of involved genes. Our results suggest that the chromatin packing pattern in rice is generally similar to that in Arabidopsis thaliana but with clear differences at specific structural levels. We conclude that genomic composition, epigenetic modification, and transcriptional activity could act in combination to shape global and local chromatin packing in rice. Our results confirm recent observations in rice and A. thaliana but also provide additional insights into the patterns and features of chromatin organization in higher plants.

Hierarchical Network Architecture for Non-Safety Applications in Urban Vehicular Ad-Hoc Networks.

In the vehicular ad-hoc networks (VANETs), wireless access in vehicular environments (WAVE) as the core networking technology is suitable for supporting safety-critical applications, but it is difficult to guarantee its performance when transmitting non-safety data, especially high volumes of data, in a multi-hop manner. Therefore, to provide non-safety applications effectively and reliably for users, we propose a hybrid V2V communication system (HVCS) using hierarchical networking architecture: a centralized control model for the establishment of a fast connection and a local data propagation model for efficient and reliable transmissions. The centralized control model had the functionality of node discovery, local ad-hoc group (LAG) formation, a LAG owner (LAGO) determination, and LAG management. The local data propagation indicates that data are transmitted only within the LAG under the management of the LAGO. To support the end-to-end multi-hop transmission over V2V communication, vehicles outside the LAG employ the store and forward model. We designed three phases consisting of concise device discovery (CDD), concise provisioning (CP), and data transmission, so that the HVCS is highly efficient and robust on the hierarchical networking architecture. Under the centralized control, the phase of the CDD operates to improve connection establishment time, and the CP is to simplify operations required for security establishment. Our HVCS is implemented as a two-tier system using a traffic controller for centralized control using cellular networks and a smartphone for local data propagation over Wi-Fi Direct. The HVCS' performance was evaluated using Veins, and compared with WAVE in terms of throughput, connectivity, and quality of service (QoS). The effectiveness of the centralized control was demonstrated in comparative experiments with Wi-Fi Direct. The connection establishment time measured was only 0.95 s for the HVCS. In the case of video streaming services through the HVCS, about 98% of the events could be played over 16 frames per second. The throughput for the streaming data was between 74% to 81% when the vehicle density was over 50%. We demonstrated that the proposed system has high throughput and satisfies the QoS of streaming services even though the end-to-end delay is a bit longer when compared to that of WAVE.

Facile Fabrication of Hierarchically Thermoresponsive Binary Polymer Pattern for Controlled Cell Adhesion.

A versatile platform allowing capture and detection of normal and dysfunctional cells on the same patterned surface is important for accessing the cellular mechanism, developing diagnostic assays, and implementing therapy. Here, an original and effective method for fabricating binary polymer brushes pattern is developed for controlled cell adhesion. The binary polymer brushes pattern, composed of poly(N-isopropylacrylamide) (PNIPAAm) and poly[poly(ethylene glycol) methyl ether methacrylate] (POEGMA) chains, is simply obtained via a combination of surface-initiated photopolymerization and surface-activated free radical polymerization. This method is unique in that it does not utilize any protecting groups or procedures of backfilling with immobilized initiator. It is demonstrated that the precise and well-defined binary polymer patterns with high resolution are fabricated using this facile method. PNIPAAm chains capture and release cells by thermoresponsiveness, while POEGMA chains possess high capability to capture dysfunctional cells specifically, inducing a switch of normal red blood cells (RBCs) arrays to hemolytic RBCs arrays on the pattern with temperature. This novel platform composed of binary polymer brush pattern is smart and versatile, which opens up pathways to potential applications as microsensors, biochips, and bioassays.

Integrated Hierarchical Cobalt Sulfide/Nickel Selenide Hybrid Nanosheets as an Efficient Three-dimensional Electrode for Electrochemical and Photoelectrochemical Water Splitting.

Developing highly active electrocatalysts for photoelectrochemical water splitting is critical to bring solar/electrical-to-hydrogen energy conversion processes into reality. Herein, we report a three-dimensional (3D) hybrid electrocatalyst that is constructed through in situ anchoring of Co9S8 nanosheets onto the surface of Ni3Se2 nanosheets vertically aligned on an electrochemically exfoliated graphene foil. Benefiting from the synergistic effects between Ni3Se2 and Co9S8, the highly conductive graphene support, and large surface area, the novel 3D hybrid electrode delivers superior electrocatalytic activity toward water reduction in alkaline media, featuring overpotentials of -0.17 and -0.23 V to achieve current densities of 20 and 50 mA cm-2, respectively, demonstrating an electrocatalytic performance on the top of the Ni3Se2- and Co9S8-based electrocatalysts as reported in literature. Experimental investigations and theoretical calculations confirm that the remarkable activity of the obtained material results from the unique 3D hierarchical architecture and interface reconstruction between Ni3Se2 and Co9S8 through Ni-S bonding, which leads to charge redistribution and thus lowers the energy barrier of hydrogen desorption in the water splitting process. Further integration of the 3D hybrid electrode with a macroporous silicon photocathode enables highly active and sustainable sunlight-driven water splitting in both basic media and real river water. The overall water splitting with 10 mA cm-2 at a low voltage of 1.62 V is achieved using our hybrid as both anode and cathode catalysts, which surpasses that of the Ir/C-Pt/C couple (1.60 V) for sufficiently high overpotentials.

Breakdown of hierarchical architecture in cellulose during dilute acid pretreatments.

Cellulose is an attractive candidate as a feedstock for sustainable bioenergy because of its global abundance. Pretreatment of biomass has significant influence on the chemical availability of cellulose locked in recalcitrant microfibrils. Optimizing pretreatment depends on an understanding of its impact on the microscale and nanoscale molecular architecture. X-ray scattering experiments have been performed on native and pre-treated maize stover and models of cellulose architecture have been derived from these data. Ultra small-angle, very small-angle and small-angle X-ray scattering (USAXS, VSAXS and SAXS) probe three different levels of architectural scale. USAXS and SAXS have been used to study cellulose at two distinct length scales, modeling the fibrils as ~30 Å diameter rods packed into ~0.14 µm diameter bundles. VSAXS is sensitive to structural features at length scales between these two extremes. Detailed analysis of diffraction patterns from untreated and pretreated maize using cylindrical Guinier plots and the derivatives of these plots reveals the presence of substructures within the ~0.14 µm diameter bundles that correspond to grouping of cellulose approximately 30 nm in diameter. These sub-structures are resilient to dilute acid pretreatments but are sensitive to pretreatment when iron sulfate is added. These results provide evidence of the hierarchical arrangement of cellulose at three length scales and the evolution of these arrangements during pre-treatments.

Dual Strategy of Morphology Optimization and Interlayer Expansion in VS2 Cathode Toward High-Performance Mg-Li Hybrid Ion Batteries.

Combining the merits of the dendrite-free formation of a Mg anode and the fast kinetics of Li ions, the Mg-Li hybrid ion batteries (MLIBs) are considered an ideal energy storage system. However, the lack of advanced cathode materials limits their further practical application. Herein, we report a dual strategy of morphology optimization and interlayer expansion for the construction of hierarchical flower-like VS2 architecture coated by N-doped amorphous carbon layers. This tailored hierarchical flower-like structure coupled with homogeneous N-doped amorphous carbon layers cooperatively provide more active sites and buffer volume changes, thus realizing the enhancement of capacity and structural stability. Moreover, the enlarged interlayer spacing caused by the cointercalation of polyvinylpyrrolidone and ammonium ions can effectively promote the charge transfer rate and facilitate the rapid ion diffusion, as further demonstrated by electrochemical results and theoretical calculations. These features endow the hierarchical flower-like VS2 cathode with superior specific energy density (644.4 Wh kg-1, average voltage of 1.2 V vs Mg2+/Mg) and excellent rate capability (181.1 mAh g-1 at 2000 mA g-1). Systematic ex situ characterization measurements are employed to reveal the ion storage mechanism, which confirms that Li+ storage plays a leading role in the capacity contribution of MLIBs. Our strategy is in favor of providing useful insights to design and construct MLIBs with high energy density and excellent rate performance.

Enhancing the supercapacitive performance of a carbon-based electrode through a balanced strategy for porous structure, graphitization degree and N,B co-doping.

Regarding carbon-based electrodes, simultaneously establishing a well-defined meso-porous architecture, introducing abundant hetero-atoms and improving the graphitization degree can effectively enhance their capacitive performance. However, it remains a significant challenge to achieve a good balance between defects and graphitization degree. In this study, the porous structure and composition of carbon materials are co-optimised through a 'dual-function' strategy. Briefly, K3Fe(C2O4)3 and H3BO3 were hybridised with a gelatin aqueous solution to form a homogeneous composite hydrogel, followed by lyophilisation and carbonisation. Owing to the dual functionality of raw materials, the graphitization, activation and hetero-atom doping processes can occur simultaneously during a one-step high-temperature treatment. The resultant carbon material exhibits a high graphitization degree (ID/IG = 0.9 ± 0.1), high hetero-atom content (N: 9.0 ± 0.3 at.%, B: 6.9 ± 0.5 at.%) and a large specific area (1754 ± 58 m2/g). The as-prepared electrode demonstrates a superior capacitance of 383 ± 1F g-1 at 1 A/g. Interestingly, the cyclic voltammetry (CV) curves exhibit a distinctive pair of broad redox peaks, which is uncommon in KOH electrolyte. Experiment data and density functional theory (DFT) simulation verify that N-5, B co-doping enhances the activity of the faradic reaction of carbon electrodes in KOH electrolyte. Furthermore, the fabricated Zn-ion hybrid supercapacitor (ZHSC) based on this carbon electrode delivers a high-energy density of 140.7 W h kg-1 at a power density of 840 W kg-1.

Attapulgite-intercalated g-C3N4/ZnIn2S4 3D hierarchical Z-scheme heterojunction for boosting photocatalytic hydrogen production.

Construction of hierarchical architecture with suitable band alignment for graphitic carbon nitride (g-C3N4) played a pivotal role in enhancing the efficiency of photocatalysts. In this study, a novel attapulgite-intercalated g-C3N4/ZnIn2S4 nanocomposite material (ZIS/CN/ATP, abbreviated as ZCA) was successfully synthesized using the freeze-drying technique, thermal polymerization, and a simple low-temperature hydrothermal method. Attapulgite (ATP) was intercalated into g-C3N4 to effectively regulate its interlayer structure. The results reveal a substantial enlargement of its internal space, thereby facilitating the provision of additional active sites for improved dispersibility of ZnIn2S4. Notably, the optimized photocatalyst, comprising a mass ratio of ATP, g-C3N4, and ZnIn2S4 at 1:1:2.5 respectively, achieves an outstanding hydrogen evolution rate of 3906.15 µmol g-1h-1, without the need for a Pt co-catalyst. This rate surpasses that of pristine g-C3N4 by a factor of 475 and ZnIn2S4 by a factor of 5, representing a significant improvement in performance. This significant enhancement can be primarily attributed to the higher specific surface area, richer active sites, broadened light response range, and efficient interfacial charge transfer channels of the ZCA composite photocatalyst. Furthermore, the Z-scheme photocatalytic mechanism for the sandwich-like layered structure heterojunction was thoroughly investigated using diverse characterization techniques. This work offers new insights for enhancing photocatalytic performance through the expanded utilization of natural minerals, paving the way for future advancements in this field.

Enhancing Composite Toughness Through Hierarchical Interphase Formation.

High strength and ductility are highly desired in fiber-reinforced composites, yet achieving both simultaneously remains elusive. A hierarchical architecture is developed utilizing high aspect ratio chemically transformable thermoplastic nanofibers that form covalent bonding with the matrix to toughen the fiber-matrix interphase. The nanoscale fibers are electrospun on the micrometer-scale reinforcing carbon fiber, creating a physically intertwined, randomly oriented scaffold. Unlike conventional covalent bonding of matrix molecules with reinforcing fibers, here, the nanofiber scaffold is utilized - interacting non-covalently with core fiber but bridging covalently with polymer matrix - to create a high volume fraction of immobilized matrix or interphase around core reinforcing elements. This mechanism enables efficient fiber-matrix stress transfer and enhances composite toughness. Molecular dynamics simulation reveals enhancement of the fiber-matrix adhesion facilitated by nanofiber-aided hierarchical bonding with the matrix. The elastic modulus contours of interphase regions obtained from atomic force microscopy clearly indicate the formation of stiffer interphase. These nanoengineered composites exhibit a ≈60% and ≈100% improved in-plane shear strength and toughness, respectively. This approach opens a new avenue for manufacturing toughened high-performance composites.

Bonding iron chalcogenides in a hierarchical structure for high-stability sodium storage.

Owing to price-boom and low-reserve of Lithium ion batteries (LIBs), cost-cutting and well-stocked sodium ion batteries (SIBs) attract a lot of attention, aiming to develop an effective energy storage and conversion equipment. As a typical anode for SIBs, Iron sulfide (FeS) is difficult to maintain the high theoretical capacity. Structural instability and inherent low conductivity limit the cyclic and rate performance of FeS. Herein, hierarchical architecture of FeS-FeSe2 coated with nitrogen-doped carbon (NC) is obtained by single-step solvothermal method and two-stage high-temperature treatments. Specifically, lattice imperfections provided by heterogeneous interfaces increase the Na+ storage sites and fasten ion/electron transfer. Synergistic effect induced by the hierarchical architecture effectively enhances the electrochemical activity and reduces the resistance, which contributes to the transfer kinetics of Na+. In addition, the phenomenon that heterogeneous interfaces provide more active site and extra migration Na+ path is also proved by density functional theory (DFT). As an anode for SIBs, FeS-FeSe2/NC (FSSe/C) delivers highly reversible capacity (704.5 mAh·g-1 after 120 cycles at 0.2 A·g-1), excellent rate performance (326.3 mAh·g-1 at 12 A·g-1) and long-lasting durability (492.3 mAh·g-1 after 1000 cycles at 4 A·g-1 with 100 % capacity retention). Notably, the full battery, assembled with FSSe/C and Na3V2(PO4)3/C (NVP/C), delivers reversible capacity of 252.1 mAh·g-1 after 300 cycles at 1 A·g-1. This work provides a facile method to construct a hierarchical architecture anode for high-performance SIBs.

Construction of NiFe(CN)5NO/Ni3S2 hierarchical submicro-rods on nickel foam as advanced oxygen evolution electrocatalysts.

The development of cheap, abundant, and highly efficient electrocatalysts for the oxygen evolution reaction (OER) is urgently needed for hydrogen production from water splitting. Herein, we demonstrate a novel OER electrocatalyst (NiFe(CN)5NO/Ni3S2) prepared by coupling Ni3S2 and a bimetallic metal-organic framework (MOF) of NiFe(CN)5NO on nickel foam (NF) via a simple two-step route. The NiFe(CN)5NO/Ni3S2 electrocatalyst displays an interesting rod-like hierarchical architecture assembled by ultrathin nanosheets. The combination of NiFe(CN)5NO and Ni3S2 optimizes the electronic structure of the metal active sites and increases the electron transfer capability. Benefitting from the synergistic effect between Ni3S2 and the NiFe-MOF as well as the unique hierarchical architecture, the NiFe(CN)5NO/Ni3S2/NF electrode exhibits excellent electrocatalytic OER activity with ultralow overpotentials of 162/197 mV at 10/100 mA cm-2 and an ultrasmall Tafel slope of 26 mV dec-1 in 1.0 M KOH, which are far superior to those of the individual NiFe(CN)5NO, Ni3S2 and commercial IrO2 catalysts. In particular, unlike common metal sulfide-based electrocatalysts, the composition, morphology and microstructure of the NiFe-MOF/Ni3S2 composite electrocatalyst can be well retained after the OER, which endows it with fantastic long-term durability. This work offers a new strategy for the construction of novel and high-efficiency MOF-based composite electrocatalysts for energy applications.

Insights into the contributions of hemicelluloses to assembly and mechanical properties of cellulose networks.

In order to explore the contributions of hemicelluloses to the assembly and mechanical properties of cellulose networks, the bacterial cellulose (BC) composites containing xylan and glucomannan were prepared to mimic the polysaccharides network of plant cell walls. Both polysaccharides could induce the change of diameters of cellulose ribbons and influence the crystallization of cellulose. Besides, small-angle X-ray scattering (SAXS) demonstrated that xylan inhibited the assembly of microfibrils into cellulose ribbons, while glucomannan promoted the packing of microfibrils. The changes of cellulose crystalline structure and assembly pattern of cellulose contributed to the lower tensile strength and higher strain at break of the BC composites as compared with the BC. The results provide a profound insight into the structure-property relationships of cellulose networks affected by hemicelluloses, which could be conducive to the development of cellulose biomaterials.

An Ultrahigh-Mass-Loading Integrated Free-Standing Functional All-Carbon Positive Electrode Prepared using an Architecture Tailoring Strategy for High-Energy-Density Dual-Ion Batteries.

Dual-ion batteries (DIBs) have been attracting great attention for the storage of stationary energy due to their low cost, environmental friendliness, and high working voltage. However, most reports on DIBs involve low-mass-loading electrodes (<2.5 mg), while the use of high mass-loading electrodes (>10 mg cm-2 ), which are critical for practical application, is overlooked. Herein, an integrated free-standing functional carbon positive electrode (named MSCG) with a "point-line-plane" hierarchical architecture at the practical level of ultrahigh mass-loading (>50 mg cm-2 ) is developed for high-energy-density DIBs. The rationally designed microstructure and the advanced assembly method that is adopted produce a well-interconnected ion/electron transport channel in the MSCG electrode, which confers rapid ion/electron kinetic properties while maintaining good mechanical properties. Consequently, the DIBs with ultrahigh-mass-loading MSCG electrodes exhibits a high discharge capacity of 100.5 mAh g-1 at 0.5 C (loading mass of 50 mg cm-2 ) and a long-term cycling performance with a capacity retention of 87.7% at 1 C after 500 cycles (loading mass of 23 mg cm-2 ). Moreover, the DIB with the ultrahigh-mass-loading positive electrode achieves a high energy density of 379 Wh kg-1 based on the mass of electrode materials, the highest value recorded to date for any DIBs.

Synthesis of a one-dimensional carbon nanotube-decorated three-dimensional crucifix carbon architecture embedded with Co7Fe3/Co5.47N nanoparticles for high-performance microwave absorption.

Low-dimensional cell-decorated three-dimensional (3D) hierarchical structures are considered excellent candidates for achieving remarkable microwave absorption. In the present work, a one-dimensional (1D) carbon nanotube (CNT)-decorated 3D crucifix carbon framework embedded with Co7Fe3/Co5.47N nanoparticles (NPs) was fabricated by the in-situ pyrolysis of a trimetallic metal-organic framework (MOF) precursor (ZIF-ZnFeCo). Co7Fe3/Co5.47N NPs were uniformly dispersed on the carbon matrix. The 1D CNT nanostructure was well regulated on the 3D crucifix surface by changing the pyrolysis temperature. The synergistic effect of 1D CNT and the 3D crucifix carbon framework increased the conductive loss, and Co7Fe3/Co5.47N NPs induced interfacial polarization and magnetic loss; thus, the composite manifested superior microwave absorption performance. The optimum absorption intensity was -54.0 dB, and the effective absorption frequency bandwidth reached 5.4 GHz at a thickness of 1.65 mm. The findings of this work could provide significant guidance for the fabrication of MOF-derived hybrids for high-performance microwave absorption applications.