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The absorption-dominated graphene porous materials, considered ideal for mitigating electromagnetic pollution, encounter challenges related to intricate structural design. Herein, petal-like graphene porous films with dendritic-like and honeycomb-like pores are prepared by controlling the phase inversion process. The theoretical simulation and experimental results show that PVP K30 modified on the graphene surface via van der Waals interactions promotes graphene to be uniformly enriched on the pore walls. Benefiting from the regulation of graphene distribution and the construction of honeycomb pore structure, when 15 wt % graphene is added, the porous film exhibits absorption-dominated electromagnetic shielding performance, compared with the absence of PVP K30 modification. The total electromagnetic shielding effectiveness is 24.1 dB, an increase of 170%; the electromagnetic reflection coefficient reduces to 2.82 dB; The thermal conductivity reaches 1.1 W/(m K), representing a 104% increase. In addition, the porous film exhibits improved mechanical properties, the tensile strength increases to 6.9 MPa, and the elongation at break increases by 131%. The method adopted in this paper to control the enrichment of graphene in the pore walls during the preparation of honeycomb porous films by the phase inversion method can avoid the agglomeration of graphene and improve the overall performance of the porous graphene porous films.
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Supercapacitor electrodes (SCs) of carbon-based materials with flexible structures and morphologies have demonstrated excellent electrical conductivity and chemical stability. Herein, a clean and cost-effective method for producing a 3D self-doped honeycomb-like carbonaceous material with KOH activation from bio-waste oyster shells (BWOSs) is described. A remarkable performance was achieved by the excellent hierarchical structured carbon (HSC-750), which has a large surface area and a reasonably high packing density. The enhanced BWOSs-derived HSC-750 shows an ultrahigh specific capacitance of 525 F/g at 0.5 A g-1 in 3 M KOH electrolyte, as well as high specific surface area (2377 m2 g-1), pore volume (1.35 cm3 g-1), nitrogen (4.70%), and oxygen (10.58%) doping contents. The SCs also exhibit exceptional cyclic stability, maintaining 98.5% of their capacitance after 10,000 charge/discharge cycles. The two-electrode approach provides a super high energy density of 28 Wh kg-1 at a power density of 250 W kg-1 in an alkaline solution, with remarkable cyclability after 10,000 cycles. The study demonstrates the innovative HSC synthesis from BWOSs precursor and cost-effective fabrication of 3D N/O self-doped heteroatom HSC for flexible energy storage.
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Carbono , Capacitância Elétrica , Eletrodos , Nitrogênio , Porosidade , Carbono/química , Nitrogênio/química , Animais , Oxigênio/química , Ostreidae/química , Condutividade ElétricaRESUMO
Designing a working electrode is crucial for the reliable electrochemistry detection, which is applied to detect toxic and harmful substances sensitively and rapidly. Here we report the polytetrafluoroethylene decomposition-assisted electrospinning, a combination method for creating nanopore and synthesizing CeF3, to prepare the self-supporting electrode of CeF3 nanoparticles-anchored on porous carbon nanofibers (CeF3/PCNFs) for highly sensitive nitrite detection. The CeF3/PCNFs exhibits remarkable electroactivity toward nitrite detection, featuring a wide concentration range (0.5 µM-6 mM), low detection limit (10 nm) and high sensitivity (2093 µA mM-1 cm-2). It also exhibits excellent selectivity, stability and reproducibility, and powerful reliability for nitrite detection in saliva, pickles, sausages, chips, river water and tap water. This study provides a facile strategy to prepare the metal fluoride-based self-supporting electrode, which overcomes the disadvantages of chemically modified electrodes unstable and poorly reproducible, and is significant for clinical diagnosis, food safety and environmental monitoring.
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Thermal management materials have become increasingly crucial for stretchable electronic devices and systems. Drastically different from conventional thermally conductive materials, which are applied at static conditions, thermal management materials for stretchable electronics additionally require strain-insensitive thermal conductivity, as they generally undergo cyclic deformation. However, realizing such a property remains challenging mainly because conventional thermally conductive polymer composites generally lack a mechanically guided design. Here, we report a honeycomb-like nanocomposite with a three-dimensional (3D) thermally conductive network fabricated by an arrayed ice-templating technique followed by elastomer infiltration. The hexagonal honeycomb-like structure with thin, compact walls (≈ 40 µm) endows our composite with a high through-plane thermal conductivity (≈ 1.54 W m-1 K-1) at an ultralow boron nitride nanosheet (BNNS) loading (≈ 0.85 vol %), with an enhancement factor of thermal conductivity up to 820% and thermal-insensitive strain up to 200%, which are 2.7 and 2 times higher than those reported in the literature. We report an intelligent strategy for the development of advanced thermal management materials for high-performance stretchable electronics.
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Although selective coronary angiography is the gold standard diagnostic technique for coronary lesions, this method does not provide all information regarding pathophysiologic mechanisms. We herein describe a patient in their early 60s with a 3-month history of pronounced angina. Coronary angiography revealed a central line of illumination in the proximomedial segment of the right coronary artery, suggesting a chronic coronary dissection/recanalized thrombus, along with positive remodeling and TIMI grade 2 flow. Optical coherence tomography showed a recanalized thrombus and multiple lumens separated by thin septa. Because of the significantly reduced flow and signs of ischemia in the right coronary artery irrigation territory, we decided to perform percutaneous coronary intervention. Post-treatment optical coherence tomography indicated optimal apposition and expansion of the stents with positive remodeling of the blood vessel. We believe that decisions regarding treatment modalities should be guided by the presence or absence of ischemia. Lesions that are causing myocardial ischemia should be revascularized; otherwise, medical treatment can be utilized.
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Doença da Artéria Coronariana , Stents Farmacológicos , Intervenção Coronária Percutânea , Trombose , Humanos , Doença da Artéria Coronariana/diagnóstico , Angiografia Coronária , Vasos Coronários/diagnóstico por imagem , Vasos Coronários/cirurgia , Vasos Coronários/patologia , Tomografia de Coerência Óptica , Trombose/patologia , Isquemia , Resultado do TratamentoRESUMO
Influences of subphase pH and temperature on the interfacial aggregation behavior of two double hydrophilic hyperbranched copolymers of poly[oligo(ethylene glycol) methacrylate-co-(2-diisopropylamino)ethyl methacrylate] (P(OEGMA-co-DIPAEMA)) at the air/water interface are studied by the Langmuir film balance technique. Morphologies of their Langmuir-Blodgett (LB) films are characterized by atomic force microscopy (AFM). At the interface, P(OEGMA-co-DIPAEMA) copolymers tend to form a dense network structure of circular micelles composed of branching agent-connected carbon backbone cores and mixed shells of OEGMA and DIPAEMA segments (pendant groups). This network structure containing many honeycomb-like holes with diameters of 6-8 nm is identified for the first time and clearly observed in the enlarged AFM images of their LB films. Under acidic conditions, surface pressure versus molecular area isotherms of the two copolymers in the low-pressure region show larger mean molecular area than those under neutral and alkaline conditions due to the lack of impediment from DIPAEMA segments. Upon further compression, each isotherm exhibits a wide pseudo-plateau, which corresponds to OEGMA segments being pressed into the subphase. Furthermore, the isotherms under neutral and alkaline conditions exhibit the lower critical solution temperature behavior of OEGMA segments, and the critical temperature is lower when the hyperbranched copolymer contains higher OEGMA content.
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Ar , Água , Água/química , Polímeros/química , Microscopia de Força Atômica , Metacrilatos/químicaRESUMO
To enrich the application of nanocomposite hydrogels, we introduced two types of nanocellulose (CNC, cellulose nanocrystals; CNF, cellulose nanofibers) into the soy protein isolate(SPI)- konjac glucomannan (KGM) composite hydrogel system, respectively. The similarities and differences between the two types of nanocellulose as textural improvers of composite gels were successfully explored, and a model was developed to elaborate their interaction mechanisms. Appropriate levels of CNC (1.0 %) and CNF (0.75 %) prolonged SPI denaturation within the system, exposed more buried functional groups, improved molecular interactions, and strengthened the honeycomb structural skeleton formed by KGM. The addition of CNC resulted in greater gel strength (SKC1 2708.53 g vs. Control 810.35 g), while the addition of CNF improved the elasticity (SKF0.75 1940.24 g vs. Control 405.34 g). This was mainly attributed to the reinforcement of the honeycomb-structured, water binding and trapping, and the synergistic effect of covalent (disulfide bonds) and non-covalent interactions (hydrogen bonds, ionic bonds) within the gel network. However, the balance and interactions between proteins and polysaccharides were disrupted in the composite system with excessive CNF addition (≥0.75 %), which broken the stability of the honeycomb-like structure. We expect this study will draw attention on potential applications of CNC and CNF in protein-polysaccharide binary systems and facilitate the creation of novel, superior, mechanically strength-regulated nanofiber composite gels.
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Hidrogéis , Proteínas de Soja , Hidrogéis/química , Celulose/química , Mananas/química , CetonasRESUMO
Introduction: Biomimetic lubricant-infused porous surfaces are developed and applied for omniphobicity and corrosion protection, which exhibit great advantages compared to superhydrophobic surfaces. Methods: Herein, superhydrophobic Fe@E-Zn@PFOA was prepared via the electrodeposition of laminated Zinc coating, further vapor etching, and post-modification with perfluoro caprylic acid. The facile, inexpensive, and environment-friendly water vapor etching process can form a porous honeycomb-like structure. Moreover, the perfluoropolyether lubricant was wicked into the porous and superhydrophobic surfaces, obtaining lubricant-infused surfaces of Fe@E-Zn@PFOA@PFPE. Results and discussion: The influences of the textured roughness and chemical composition on the surface wettability were systematically investigated. The Fe@E-Zn@PFOA@PFPE performs omniphobicity with small sliding angles and superior corrosion resistance compared with the superhydrophobic surface, owing to their multiple barriers, including infused lubricant, hydrophobic monolayers, and compact Zn electroplating coating. Thus, the proposed lubricant-infused surface may provide insights into constructing protective coatings for the potential applications of engineering metal materials.
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SiOx anodes are garnering significant interest in lithium-ion batteries (LIBs) due to theirs low voltage plateau and high capacity. However, critical drawbacks, including high expansion rate and low electronic conductivity, severely limit their practical applications. While 0D, 1D, and 2D scale nanostructures have been proven to mitigate these issues, these materials tend to accumulate after prolonged cycling, leading to adverse effects on the mass transfer processes within the electrode. Herein, we have developed a honeycomb-like SiOx/C nanoarchitecture with carbon coating based on a 3D ordered macroporous (3DOM) structure. The 3D interconnected pore windows facilitate the diffusion and transport of lithium ions (Li+) in the electrolyte, and the extremely thin walls (<15 nm) provide a shorter transport path for Li+ in the solid. The carbon cladding buffers volume expansion and enhances electronic conductivity. The as-prepared anode demonstrates a high reversible capacity of 1068 mAh/g and an initial coulombic efficiency of 70.7 %. It maintains a capacity of 644 mAh/g (capacity retention of 84.63 %) even at a high current of 1.0 A/g after 700 cycles. The unique honeycomb-like structure offers enormous insights into the study of energy storage in 3D materials.
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A 71 year old male patient who experienced acute myocardial infarction (AMI) 4 years ago and had a history of polycythemia vera and thrombocythemia was admitted because acute attack of chronic heart failure. Coronary angiography revealed an unusual filling defect in the middle segment of the left anterior descending (LAD) coronary artery and IVUS showed it is a HLS which is different from dissection or woven coronary artery. We review the recent literature of HLS in this article and further investigations are warranted for the optimal management of HLS.
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Policitemia Vera , Trombocitose , Trombose , Masculino , Humanos , Idoso , Vasos Coronários/diagnóstico por imagem , Policitemia Vera/complicações , Policitemia Vera/diagnóstico por imagem , Angiografia Coronária , Ultrassonografia de IntervençãoRESUMO
BACKGROUND: Porous carbon electrode (PCE) is identified as a highly suitable electrode material for commercial application due to its production process, which is characterized by simplicity, cost-effectiveness and environmental friendliness. PCE was synthesized using torch ginger (Etlingera elatior (Jack) R.M. Smith) leaves as the base material. The leaves were treated with different concentrations of ZnCl2 , resulting in a supercapacitor cell electrode with unique honeycomb-like three-dimensional (3D) morphological pore structure. This PCE comprises nanofibers from lignin content and volatile compounds from aromatic biomass waste. RESULTS: From the characterization of physical properties, PCE-0.3 had an impressive amorphous porosity, wettability and 3D honeycomb-like structural morphology with a pore framework consisting of micropores and mesopores. According to the structural advantages of 3D hierarchical pores such as interconnected honeycombs, PCE-0.3 as supercapacitor electrode had a high specific capacitance of up to 285.89 F g-1 at 1 A. Furthermore, the supercapacitor exhibited high energy and power density of 21.54 Wh kg-1 and 161.13 W kg-1 , respectively, with a low internal resistance of 0.059 Ω. CONCLUSION: The results indicated that 3D porous carbon materials such as interconnected honeycombs derived from the aromatic biomass of torch ginger leaves have significant potential for the development of sustainable energy storage devices. © 2023 Society of Chemical Industry.
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Zingiber officinale , Carbono/química , Biomassa , Eletrodos , LigninaRESUMO
Manipulating electronic structure of alloy-based electrocatalysts can eagerly regulate its catalytic efficiency and corrosion resistance for water splitting and fundamentally understand the catalytic mechanisms for oxygen/hydrogen evolution reactions (OER/HER). Herein, the metallic Co-assisted Co7 Fe3 alloy heterojunction (Co7 Fe3 /Co) embeds in a 3D honeycomb-like graphitic carbon is purposely constructed as a bifunctional catalyst for overall water splitting. As-marked Co7 Fe3 /Co-600 displays the excellent catalytic activities in alkaline media with low overpotentials of 200 mV for OER and 68 mV for HER at 10 mA cm-2 . Theoretical calculations reveal the electronic redistribution after coupling Co with Co7 Fe3 , which likely forms the electron-rich state over interfaces and the electron-delocalized state at Co7 Fe3 alloy. This process changes the d-band center position of Co7 Fe3 /Co and optimizes the affinity of catalyst surface to intermediates, thus promoting the intrinsic OER/HER activities. For overall water splitting, the electrolyzer only requires a cell voltage of 1.50 V to achieve 10 mA cm-2 and dramatically retains 99.1% of original activity after 100 h of continuous operation. This work proposes an insight into modulation of electronic state in alloy/metal heterojunctions and explores a new path to construct more competitive electrocatalysts for overall water splitting.
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The existence of carcinogenic nitrites in food and the natural environment has attracted much attention. Therefore, it is still urgent and necessary to develop nitrite sensors with higher sensitivity and selectivity and expand their applications in daily life to protect human health and environmental safety. Herein, one-dimensional honeycomb-like carbon nanofibers (HCNFs) were synthesized with electrospun technology, and their specific structure enabled controlled growth and highly dispersed bismuth nanoparticles (Bi NPs) on their surface, which endowed the obtained Bi/HCNFs with excellent electrocatalytic activity towards nitrite oxidation. By modifying Bi/HCNFs on the screen-printed electrode, the constructed Bi/HCNFs electrode (Bi/HCNFs-SPE) can be used for nitrite detection in one drop of solution, and exhibits higher sensitivity (1269.9 µA mM-1 cm-2) in a wide range of 0.1~800 µM with a lower detection limit (19 nM). Impressively, the Bi/HCNFs-SPE has been successfully used for nitrite detection in food and environment samples, and the satisfactory properties and recovery indicate its feasibility for further practical applications.
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The electrochemical CO2 reduction (ECR) of high-value multicarbon products is an urgent challenge for catalysis and energy resources. Herein, we reported a simple polymer thermal treatment strategy for preparing honeycomb-like CuO@C catalysts for ECR with remarkable C2H4 activity and selectivity. The honeycomb-like structure favored the enrichment of more CO2 molecules to improve the CO2-to-C2H4 conversion. Further experimental results indicate that the CuO loaded on amorphous carbon with a calcination temperature of 600 °C (CuO@C-600) has a Faradaic efficiency (FE) as high as 60.2% towards C2H4 formation, significantly outperforming pure CuO-600 (18.3%), CuO@C-500 (45.1%) and CuO@C-700 (41.4%), respectively. The interaction between the CuO nanoparticles and amorphous carbon improves the electron transfer and accelerates the ECR process. Furthermore, in situ Raman spectra demonstrated that CuO@C-600 can adsorb more adsorbed *CO intermediates, which enriches the CC coupling kinetics and promotes C2H4 production. This finding may offer a paradigm to design high-efficiency electrocatalysts, which can be beneficial to achieve the "double carbon goal."
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Honeycomb-like Ni(OH)2/Ni3S2/Ni foam (NF) was fabricated via a two-step hydrothermal process and subsequent alkalization. Ni3S2 with a honeycombed structure was in-situ synthesized on the NF surface by a hydrothermal process. MOF-derived Ni(OH)2 nanosheets were then successfully grown on the Ni3S2/NF surface by a second hydrothermal process and alkaline treatment, and a large number of nanosheets were interconnected to form a typical honeycomb-like structure with a large specific surface area and porosity. As a binder-free electrode, the prepared honeycomb-like Ni(OH)2/Ni3S2/NF exhibited a high specific capacitance (2207 F·g-1 at 1 A·g-1, 1929.7 F·g-1 at 5 mV·s-1) and a remarkable rate capability and cycling stability, with 62.3% of the initial value (1 A·g-1) retained at 10 A·g-1 and 90.4% of the initial value (first circle at 50 mV·s-1) retained after 5000 cycles. A hybrid supercapacitor (HSC) was assembled with Ni(OH)2/Ni3S2/NF as the positive electrode and activated carbon (AC) as the negative electrode and exhibited an outstanding energy density of 24.5 Wh·kg-1 at the power density of 375 W·kg-1. These encouraging results render the electrode a potential candidate for energy storage.
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Doping engineering in nanostructured carbon materials is an effective approach to modify heteroatom species and surface electronic structures. Herein, an advanced electrode material based on a honeycomb-like porous carbon matrix with tunable N-doped configurations is prepared via 4,4'-bipyridine (4,4'-bpy)-assisted pyrolysis of SiO2@ZIF-8 templates and subsequent etching treatment. Interestingly, the amounts of pyridinic-N and graphitic-N can be controlled by rationally varying the content of 4,4'-bpy which acts as the N source in the pyrolysis process. Both experimental results and density functional theory calculations have revealed that synergistically with 3D interconnected porous architecture, pyridinic-N and graphitic-N have different effects on the electrochemical performances in aqueous and ionic liquid gel electrolytes for symmetric supercapacitors. Highly exposed pyridinic-N endows the carbon electrode with a strengthened pseudocapacitance contribution manifested as a high specific capacitance of 436.1 F g-1 and exceptional stability of almost 100% capacitance retention after 5000 cycles at 10 A g-1 in the KOH/polyvinyl alcohol (PVA) electrolyte. By contrast, graphitic-N is propitious for reinforced electrical double-layer capacitance contribution, reflected by a maximum energy density of 125.4 Wh kg-1 in the 1-ethyl-3-methylimidazolium tetrafluoroborate/poly(vinylidene fluoride-co-hexafluoropropylene) (EMIMBF4/PVDF-HFP) electrolyte. This work offers an in-depth insight into the understanding of the energy storage mechanism of N-rich carbon electrodes in different electrolyte media.
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The macroporous honeycomb-like MgO (MHM) had been successfully prepared by hard template method using polystyrene (PS) spheres with different particle sizes of about 400, 600, and 800 nm, respectively. The adsorption performance (3700, 3470, and 3087 mg/g) and specific surface areas (64.0, 51.4, and 34.4 m2/g) of MHM materials were inversely proportional to their pore diameters. Among the prepared MHM materials, MHM-400 exhibited the most excellent adsorption performance of 3700 mg/g towards Pb(II) at 25 °C. In this study, the macropore size in MHM played a major role in the adsorption process; Dubinin-Radushkevich (D-R) model further indicated that Pb(II) removal by MHM-400 was dominated by chemical adsorption. The thermodynamic analysis (ΔG0 < 0, ΔH0 > 0, and ΔS0 > 0) revealed that the Pb(II) adsorption was spontaneous and endothermic. After storing for 360 days, the Pb(II) removal efficiency of MHM-400 was still higher than 98.2%, exhibiting ultra-long life for Pb(II) capture. MHM-400 also exhibited high anti-interference ability towards typically coexisting ions (Na+ and K+). According to the density functional theory (DFT) calculation, the Pb could be adsorbed on the top site of the oxygen atom at the surface of the cubic MgO (200) plane; the adsorption energy (Ead) was 0.159 eV. The XRD and FTIR analyses revealed the further formation of Pb3(CO3)2(OH)2 and PbO after Pb(II) adsorption. Furthermore, MHM-400 could effectively remove both Cd(II) and Pb(II) ions from wastewater within 20 min, and the adsorption efficiency achieved > 99%, suggesting that MHM-400 was a potential material for effective Pb(II) removal.
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Chumbo , Óxido de Magnésio , Poluentes Químicos da Água , Adsorção , Concentração de Íons de Hidrogênio , Íons , Cinética , Chumbo/química , Óxido de Magnésio/química , Termodinâmica , Poluentes Químicos da Água/análiseRESUMO
Layered double hydroxides are considered promising electrode materials for the preparation of high-energy-density supercapacitors owing to their suitable microstructure and significant electrochemical properties. In this study, honeycomb-like NiMn-layered double-hydroxide (NiMn-LDH) nanosheet arrays with numerous electron/ion channels, a large number of active sites, considerable redox reversibility, and significant electrical conductivity were synthesized by combining Co2(OH)2CO3 nanoneedle arrays with NiMn-LDH nanosheet arrays and Ag nanoparticles on a carbon cloth (CC) substrate through a hydrothermal strategy (CC@Co2CH/NM-LDH-Ag). The fabricated CC@Co2CH/NM-LDH-Ag binder-free electrode exhibited a high specific capacitance of 10,976 mF cm-2 (3092F/g, 1391.4C g-1) at 2 mA cm-2 (1 A/g), and a high capacitance retention of 93.2 % after 10,000 cycles at a current density of 20 mA cm-2. In addition, a solid-state asymmetric supercapacitor (ASC) device assembled using CC@Co2CH/NM-LDH-Ag as the cathode possessed an ultrahigh energy density of 68.85 Wh kg-1 at a power density of 722.6 W kg-1, and two fabricated ASC units in series were able to power a multifunctional display for more than 30 min. Therefore, this study provides a new approach for the design and synthesis of high-performance flexible electrodes.
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Sodium-sulfur batteries operating at ambient temperature are being extensively studied because of the high theoretical capacity and abundant resources, yet the long-chain polysulfides' shuttle effect causes poor cycling performance of Na-S batteries. We report an annealing/etching method to converse low-cost wheat bran to a 3D honeycomb-like carbon with abundant micropores (WBMC), which is smaller than S8 molecular size (â¼0.7 nm). Thus, the microporous structure could only fill small molecular sulfur (S2-4). The micropores made sulfur a one-step reaction without the shuttle effect due to the formed short-chain polysulfides being insoluble. The WBMC@S exhibits an excellent initial capacity (1413 mAh g-1) at 0.2 C, outstanding cycling performance (822 mAh g-1 after 100 cycles at 0.2 C), and high rate performance (483 mAh g-1 at 3.0 C). The electrochemical performance proves that the steric confinement of micropores effectively terminates the shuttle effect.
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In the present work, a facile one-step methodology was used to synthesize honeycomb-like BiFeO3/g-C3N4 composites, where the well-dispersed BiFeO3 strongly interacted with the hg-C3N4. The 10BiFeO3/hg-C3N4 could completely degrade RhB under visible light illumination within 60 min. The degradation rate constant was remarkably improved and approximately three times and seven times that of pristine hg-C3N4 and BiFeO3, respectively. This is ascribed to the following factors: (1) the unique honeycomb-like morphology facilitates the diffusion of the reactants and effectively improves the utilization of light energy by multiple reflections of light; (2) the charged dye molecules can be tightly bound to the spontaneous polarized BiFeO3 surface to form the Stern layer; (3) the Z-scheme heterojunction and the ferroelectric synergistically promoted the efficient separation and migration of the photogenerated charges. This method can synchronously tune the micro-nano structure, surface property, and internal field construction for g-C3N4-based photocatalysts, exhibiting outstanding potential in environmental purification.