N-doped Carbon Foam Research Articles

MoS2/N-doped hollow carbon foam for thermal insulation and broadband electromagnetic wave absorption

In this study, we demonstrated the synthesis of MoS2/N-doped hollow carbon foam (MoS2/NCF) for high performance of electromagnetic wave absorption (EMA), through high-temperature pyrolysis melamine foam and hydrothermal reaction. By adjusting the electromagnetic parameters of N-doped hollow carbon foam (NCF) through MoS2 nanosheets, the effective absorption bandwidth of MoS2/NCF reached 9.62 GHz at the matching thickness was 2.3 mm. Radar cross section (RCS) simulation results demonstrated that MoS2/NCF exhibited a strong reduction ability of RCS. At room temperature, the composite MoS2/NCF could block radiation temperature of around 110 ℃ in the case of a thickness of only 7 mm and a heating plate at 200 ℃. Moreover MoS2/NCF exhibited thermal stability and a certain flame retardants ability. The result indicated that the composite MoS2/NCF was beneficial for its application in the fields of thermal insulation and electromagnetic wave absorption.

N-Doped Carbon Nanowire-Modified Macroporous Carbon Foam Microbial Fuel Cell Anode: Enrichment of Exoelectrogens and Enhancement of Extracellular Electron Transfer.

Microbial fuel cell (MFC) performance is affected by the metabolic activity of bacteria and the extracellular electron transfer (EET) process. The deficiency of nanostructures on macroporous anode obstructs the enrichment of exoelectrogens and the EET. Herein, a N-doped carbon nanowire-modified macroporous carbon foam was prepared and served as an anode in MFCs. The anode has a hierarchical porous structure, which can solve the problem of biofilm blockage, ensure mass transport, favor exoelectrogen enrichment, and enhance the metabolic activity of bacteria. The microscopic morphology, spectroscopy, and electrochemical characterization of the anode confirm that carbon nanowires can penetrate biofilm, decrease charge resistance, and enhance long-distance electron transfer efficiency. In addition, pyrrolic N can effectively reduce the binding energy and electron transfer distance of bacterial outer membrane hemin. With this hierarchical anode, a maximum power density of 5.32 W/m3 was obtained, about 2.5-fold that of bare carbon cloth. The one-dimensional nanomaterial-modified macroporous anodes in this study are a promising strategy to improve the exoelectrogen enrichment and EET for MFCs.

Magnetic Carbon Foam Adorned with Co/Fe Nanoneedles as an Efficient Activator of Oxone for Oxidative Environmental Remediation: Roles of Surficial and Chemical Enhancement

As heterogeneous catalysis is a practical method for activating Oxone, the immobilization of transition metals (e.g., Co, Fe) on carbonaceous supports is a promising platform. Thus, this study attempts to develop a carbon-supported metallic catalyst by growing Co/Fe on carbon foam (CF) via adopting melamine foam as a readily available template which could be transferred to nitrogen-doped CF with marcoporous structures. Specifically, a unique adornment of Co/Fe species on this CF is facilely fabricated through a complexation of Co/Fe with a plant extract, tannic acid, on melamine foam, followed by carbonization to produce nano-needle-like Co/Fe on N-doped CF, forming a magnetic CF (MCF). This resultant MCF exhibits a much higher surface area of 54.6 m2/g than CF (9.5 m2/g), and possesses a much larger specific capacitance of 9.7 F/g, than that of CF as 4.0 F/g. These superior features of MCF enable it to accelerate Oxone activation in order to degrade an emerging contaminant, bis(4-hydroxyphenyl)methanone (BHPM). Furthermore, MCF + Oxone exhibits a lower activation energy as 18.6 kJ/mol for BHPM elimination and retains its effectiveness in eliminating BHPM over multiple rounds. More importantly, the CF is also prepared and directly compared with the MCF to study the composition-structure-property relationship to provide valuable insights for further understanding of catalytic behaviors, surficial characteristics, and application of such a functional carbon material.

Surface morphology of magnetic carbon foam regulated electromagnetic properties for microwave absorption

Electromagnetic pollution resulting from the electronic communication can be mitigated by using microwave absorbers. The magnetic N-doped carbon foams with diverse surface morphologies as absorbers were synthesized via alkalization treatment, hydrothermal reaction, and carbothermic reduction reaction. The microstructure, electromagnetic parameters, and microwave absorption properties can be tailored by adjusting thermal treatment temperatures. The results indicated that the composites exhibit exceptional microwave absorption properties, with a minimum reflection loss of −44.15 dB at 11.18 GHz and an effective absorption bandwidth of 5.3 GHz at a thickness of 1.53 mm. The exceptional microwave absorption properties can be attributed to the synergistic effect of superior impedance matching, robust dielectric loss, and magnetic loss. The far-field radar cross section (RCS) is also reduced, achieving a maximum RCS reduction value of 14.6 dBm2. The present study presents a novel concept for the fabrication of lightweight and broadband microwave absorbing materials.

Field-assisted conductive substrate sparks the redox kinetics of Co9S8 in Li- and Na-ion batteries

As a promising candidate electrode material in both Li- and Na-ion batteries (L/SIBs), the application of Co9S8 is being hindered by its unsatisfactory electrochemical performance caused by the sluggish ion diffusion kinetics and drastic volume expansion. Herein, a hybrid material composed of Co9S8−x, N-doped carbon foam that seeded with Co nanoparticles (Co9S8−x@Co-NC) is constructed. Particularly, theoretical and experimental results imply that a built-in electric field at the interface of Co and NC is observed due to the variation of Fermi levels, forming rich Mott-Schottky-like heterointerfaces, which can significantly enhance the charge transfer capability between the active materials of Co9S8 and conductive NC skeleton. Moreover, the sulfur defects in Co9S8−x can not only effectively lower the energy barrier of the ion diffusion and charge transfer processes, but also endow the target sample with more storage/adsorption/active sites for Li+/Na+ ions, thus improving the rate performance of the Co9S8−x@Co-NC composite. As a result, the Co9S8−x@Co-NC exhibits fast surface-controlled redox kinetics and robust cycling stability. For instance, the Co9S8−x@Co-NC displays impressive Li-storage properties in both half and full cells with a high reversible capacity of 1007.4 mA h g−1 at 0.1 A g−1 after 100 cycles and superior rate capability up to 5 A g−1. Moreover, based on these comprehensive merits, the Co9S8−x@Co-NC composite shows decent electrochemical performance (472.2 and 311.1 mA h g−1 at 0.1 and 10 A g−1, respectively) as an anode for SIBs. This work presents an effective strategy for the construction of Mott-Schottky-like heterointerfaces in Co9S8 based materials and provides specific inspiration for future works designing high-performance electrodes via interfacial engineering.

Porous CoO/carbon foam composites synthesized by solvothermal method for supercapacitor and enhanced microwave absorption applications

Composite materials comprising porous carbon foam and transition metal oxides exhibit significant potential for applications as supercapacitor electrodes and electromagnetic microwave absorbers. In this work, N-doped three-dimensional carbon foam was obtained by carbonizing melamine foam, and subsequently, a solvothermal method was used to construct a 0D/3D structure by integrating CoO nanoparticles with the three-dimensional carbon foam. The carbon foam serves dual purpose as a growth substrate and a conductive framework, effectively enhancing the electronic conductivity between the components and mitigating issues related to CoO nanoparticle aggregation. Due to the synergistic effect of pseudocapacitance and double-layer capacitance, CoO/CF exhibits enhanced supercapacitor performance, demonstrating an outstanding specific capacitance of 221 F g−1 at 1 A g−1, and surpassing that of individual component. The assembled asymmetric supercapacitor achieves a satisfactory energy density of 28.8 Wh kg−1 at a power density of 804.3 W kg−1, and retains 80.3 % of its initial capacitance after 5000 cycles at 10 A g−1. Furthermore, the microstructure was designed by the combination of carbon foam's excellent dielectric loss and CoO's magnetic loss compensating for the magnetic loss deficiency of carbon foam, thereby significantly enhancing the composite's capacity for electromagnetic wave absorption. At a thickness of 3 mm, the composite attains a minimum RL value of −14.1 dB at 14 GHz, with an effective absorption frequency width of 2.1 GHz. This well-designed and adjustable composite strategy holds great promise for applications in the fields of supercapacitors and microwave absorption.

Highly-Exposed Co-CoO Derived from Nanosized ZIF-67 on N-Doped Porous Carbon Foam as Efficient Electrocatalyst for Zinc-Air Battery.

Non-precious-metal based electrocatalysts with highly-exposed and well-dispersed active sites are crucially needed to achieve superior electrocatalytic performance for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) toward zinc-air battery (ZAB). Herein, Co-CoO heterostructures derived from nanosized ZIF-67 are densely-exposed and strongly-immobilized onto N-doped porous carbon foam (NPCF) through a self-sacrificial pyrolysis strategy. Benefited from the high exposure of Co-CoO heterostructures and the favorable mass and electron transfer ability of NPCF, the Co-CoO/NPCF electrocatalyst exhibits remarkable performance for both ORR (E1/2 =0.843V vs RHE) and OER (Ej=10mAcm-2 =1.586V vs RHE). Further application of Co-CoO/NPCF as the air-cathode in rechargeable ZAB achieves superior performance for liquid-state ZAB (214.1mWcm-2 and 600 cycles) and flexible all-solid-state ZAB (93.1mWcm-2 and 140 cycles). Results from DFT calculations demonstrate that the electronic metal-support interactions between Co-CoO and NPCF via abundant C-Nx sites is favorable for electronic structure modulation, accounting for the remarkable performance.

A vapor-liquid-solid mechanism for in-situ deposition of ultra-small hollow MoS2 nanoparticles in N-doped carbon foam as an anode of lithium-ion batteries

Although molybdenum disulfide (MoS2) has been nominated as a high theoretical capacity anode material for lithium-ion batteries (LIBs), intrinsic low electrical conductivity and massive volume expansion are significant obstacles to its application investment. Herein, a novel synthesis method has been developed to prepare the carbon foam/MoS2 (CF/MoS2) nanocomposite through an in-situ vapor-liquid-solid (VLS) mechanism to overcome its inherent disadvantages as a LIBs anode. A newfound MoS-polyHIPE, polyHIPE containing Mo and S precursors, was synthesized to provide the reaction confinement spaces. The in-situ reaction between sodium molybdate melt and gaseous sulfur products derived from decomposing the S precursor in the highly nanoporous polymer during low-temperature pyrolysis (700 °C) led to the precipitation of MoS2 nanoparticles in the carbon backbone. The X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman analysis demonstrated the formation of 1T/2H-MoS2. The TEM and HAADF-STEM micrographs revealed the ultra-small MoS2 nanoparticles with a hollow spherical shape well-distributed in the carbon framework. The unique composite structure of the homogeneously dispersed tiny nanoparticles in a nanoporous matrix caused fast diffusion of lithium ions, separated MoS2 nanoparticles without aggregation, and structural stability. The prepared composite exhibited a high specific capacity of 1051 mAh g−1 after 100 charge/discharge cycles. The composite also exhibited a significant specific capacity of 600 mAh g−1 at the high current density of 3C as an anode material for LIBs.

Electrocatalytic performance of Ni-promoted Co nanoclusters supported by N-doped carbon foams for rechargeable Zn-air batteries

Ni/Co diatomic clusters supported on nitrogen-doped carbon foams are prepared via molten salt method to improve the density of surface active sites of zinc-air battery catalysts and further explore metal-modified carbon-based catalysts. The influence of Co and Ni atoms on the carbon foam structure is investigated by X-ray diffraction and high-resolution electron microscopy, and the presence of metal atoms in N-doped carbon foams is confirmed by X-ray spectroscopy. The left shift of the diffraction peak of Co doped graphitic carbon indicates an increase in the interlayer spacing and a reduced graphitization degree, while the introducton of Ni atoms promotes graphitization. For Ni–Co/NFC-2, Ni inhibits the insertion of Co in carbon layer by increasing graphitization, thus exposing more Co-active substances on the surface, which is important for improving the catalytic process of ORR and OER. According to electrochemical tests, Ni–Co co-doped carbons exhibited superior bi-functional electrocatalytic performance with oxygen reduction reaction (ORR) Eonset = 0.97 V and a Tafel slope of 49.5 mV dec−1, accompanied by oxygen evolution reaction (OER) Ej = 10 mA cm−2 = 1.46 V. Zinc-air battery (ZAB) cell, utilizing the developed material as a catalyst, exhibited a high discharge power density of 138 mW cm−2 with stable performance for up to 200 h.

Synergistically Achieving Superior Sodium Storage of Metal Selenides by Constructing N-Doped Carbon Foams and Utilizing Cu-Driven Replacement Reaction.

Metal selenides are considered as one of the most promising anode materials for Na-ion batteries owing to high specific capacity and relatively higher electronic conductivity compared with metal sulfides or oxides. However, such anodes still suffer from huge volume change upon repeated Na+ insertion/extraction processes and simultaneously undergo severe shuttle effect of polyselenides, thus leading to poor electrochemical performance. Herein, a facile chemical-blowing and selenization strategy to fabricate 3D interconnected hybrids built from metal selenides (MSe, M = Mn, Co, Cr, Fe, In, Ni, Zn) nanoparticles encapsulated in in situ formed N-doped carbon foams (NCFs) is reported. Such hybrids not only provide ultrasmall active nanobuilding blocks (≈15nm), but also efficiently anchor them inside the conductive NCFs, thus enabling both high-efficiency utilization of active components and high structural stability. On the other hand, Cu-driven replacement reaction is utilized for efficiently inhibiting the shuttle effect of polyselenides in ether-based electrolyte. Benefiting from the combined merits of the unique MSe@NCFs and the utilization of the conversion of metal selenides to copper selenides, the as-obtained hybrids (MnSe as an example) exhibit superior rate capability (386.6 mAh g-1 up to 8 A g-1 ) and excellent cycling stability (347.7 mAh g-1 at 4.0 A g-1 after 1200 cycles).

Hierarchically Structured Three-Dimensional Carbon-Based Integrated Electrodes with Enhanced Pseudocapacitance and Deformability

Open AccessRenewablesRESEARCH ARTICLES14 Jan 2023Hierarchically Structured 3D Carbon Based Integrated Electrodes with Enhanced Pseudocapacitance and Deformability Bo-Hao Xiao, Wei-Jie Cai, Pei-Yuan Wu, Kang Xiao and Zhao-Qing Liu Bo-Hao Xiao Google Scholar More articles by this author , Wei-Jie Cai Google Scholar More articles by this author , Pei-Yuan Wu Google Scholar More articles by this author , Kang Xiao Google Scholar More articles by this author and Zhao-Qing Liu Google Scholar More articles by this author https://doi.org/10.31635/renewables.023.202200009 SectionsSupplemental MaterialAboutPDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareFacebookTwitterLinked InEmail Compressible supercapacitors are playing an increasingly significant role in flexible sensors and wearable electronic devices. However, the integration of mechanical compressibility and excellent electrochemical performance into a single device remains a challenge. Herein, we demonstrate a compressible and high-performance supercapacitor based on an elastomer N-doped carbon foam with hierarchical carbon nanotubes. Hierarchically structured Fe3[email protected] carbon nanotubes/N-doped carbon foam and [email protected] carbon nanotubes/N-doped carbon foam have been synthesized via a simple and universal self-catalytic strategy. The hierarchical structural features of self-catalytic N-doped carbon nanotubes can serve as a cushion when the composite is subjected to an external force, exhibiting excellent mechanical properties with a maximum compressive strain of 80% and fatigue resistance of 1000 cycles. Moreover, the different electroactive potentials of the transition metal species in the composites afford the assembled device to possess a maximum operating voltage of 1.4 V, which shows a maximum energy density of ∼10.74 Wh kg−1 (0.084 mWh cm−3) at the power density of ∼179.2 W kg−1 (1.4 mWh cm−3), and retains 88.4% of the original capacitance after 20 000 charge-discharge cycles, even at a strain of 80%. This work paves the way for controllable fabrication of compressible electrodes and supercapacitors. Download figure Download PowerPoint Previous articleNext article FiguresReferencesRelatedDetails Issue AssignmentVolume 0Issue jaPage: 1-27Supporting Information Copyright & Permissions© 2023 Chinese Chemical Society Downloaded 1 times PDF downloadLoading ...

Poly (acrylamide-co-acrylonitrile) hydrogel-derived iron-doped carbon foam electrocatalyst for enhancing oxygen reduction reaction in microbial fuel cell

Developing advanced non-precious metal catalysts for oxygen reduction reaction (ORR) is critical for microbial fuel cells (MFCs). Fe–N–C catalysts are considered the best successor to platinum-based catalysts for ORR. Herein, we have synthesized environmental friendly, cost-effective Fe–N-doped carbon foam catalyst [Fe-embedded poly (acrylamide-co-acrylonitrile) hydrogel-based carbon foam(Fe@Am-co-An/CF)] by using Fe-embedded poly (Am-co-An) hydrogel for MFCs. Poly(Am-co-An) hydrogel is used as a carbon and nitrogen precursor. The synthesized catalysts are characterized by FTIR, SEM, TEM, XRD and XPS. Furthermore, four different catalysts based on different ratios of the metal such as Fe@Am-co-An/CF (1:22), Fe@Am-co-An/CF (2:22), Fe@Am-co-An/CF (3:22), and Am-co-An/CF have been prepared. Results indicate that the Fe@Am-co-An/CF (2:22) catalyst exhibits the highest power density (736.06 mWm−2 at the current density of 1132.04 mAm−2) compared to the other catalysts. The results of CV, LSV, EIS, and chronoamperometry indicate that Fe@Am-co-An/CF (2:22) is the most promising catalyst for ORR activity in MFCs.

Bimetallic FeCo phosphide nanoparticles anchored on N-doped carbon foam for wide pH hydrogen evolution reaction

Transition metal phosphides (TMPs) have considered as excellent electrocatalysts with high reactivity for hydrogen evolution reaction (HER). While electro-catalytic properties of TMPs are restricted by uneven dispersion, small surface area, poor conductivity, and unsatisfied stability. Herein, a facile procedure was proposed to prepare a hierarchical structure of FeCoP nanoparticles anchored on N-doped carbon/multi-walled carbon nanotubes (NC/CNT) nanocomposites. With the increased porosity and conductive network of NC/CNT substrate, the as-synthesized NC/CNT-FeCoP provided abundant active sites for HER. Meanwhile, due to the synergistic effect between the dual metal centers and uniform distribution of bimetallic composites, the synthesized electrocatalyst can provide enhanced intrinsic activity. Therefore, the optimized NC/CNT-FeCoP delivered excellent HER activity in 1.0 M KOH and 0.5 M H2SO4 with overpotentials of 182 mV and 150 mV at 10 mA cm−2, respectively. Moreover, NC/CNT-FeCoP coupled two-electrode system needs a low cell potential of 1.68 V at 10 mA cm−2 for overall water splitting. First-principle calculations indicated that N-doped graphene substrate can adjust the electronic properties of surface metal site and consequently affect the H adsorption strength to yield an improved HER activity. Our work demonstrated that the combination of mesoporous conductive matrices with bimetallic phosphides could greatly improve the HER efficiency for electrocatalysis.

Palladium Decorated N-Doped Carbon Foam as a Highly Active and Selective Catalyst for Nitrobenzene Hydrogenation.

Carbon foam was synthesized by the carbonization of 4-nitroaniline. The reaction is an alternative of the well-known “carbon snake” (or sugar snake) demonstration experiment, which leads to the formation of nitrogen-doped carbon foils due to its nitrogen content. The synthesized carbon foils were grinded to achieve an efficient catalyst support. Palladium nanoparticles were deposited onto the surface of the support, which showed continuous distribution. The prepared Pd nanoparticle decorated carbon foils showed high catalytic activity in nitrobenzene hydrogenation. By applying the designed catalyst, total nitrobenzene conversion, a 99.1 n/n% aniline yield, and an exceptionally high selectivity (99.8 n/n%) were reached. Furthermore, the catalyst remained active during the reuse tests (four cycles) even without regeneration.

A highly compressible, nitrogen doped carbon foam based all pseudo-capacitance asymmetric supercapacitors

Compressible supercapacitors are playing an increasingly significant role in sensors and wearable electronic devices. However, compressible supercapacitors have a limited specific capacity as well as lower working voltage. In this work, three-dimensional (3D) N-doped carbon foam is being explored for fabrication of a compressible supercapacitor with pseudocapacitive spinel. The fact that self-growing ZnFe2O4 on highly compressible nitrogen doped carbon foam composite electrodes can deliver significant pseudo-capacitance at negative potentials, an all-pseudocapacitive asymmetric supercapacitor device is fabricated by combining it with NiCo2O4 cathode. The composite electrodes combine the superior electrochemical and mechanical performances with maximum compressive strain of 80% and durability (cyclic strains up to 500 times under the strain of 60%). The asymmetric supercapacitor demonstrates an energy density of 11.84 Wh kg−1 (0.39 mWh cm−3) at 300 W kg−1 (10 mW cm−3), with 96.5% capacitance retention after 15 000 charge-discharge cycles at the compressive strain of 60%. Our work provides new insights for the design of compressible supercapacitors with high performance and accelerates the development of a new generation in energy storage devices with compressibility.

Oxygen-rich graphene vertically grown on 3D N-Doped carbon foam for high-performance sodium ion batteries

Graphene is emerged as one of the promising anodes for sodium ion batteries (SIBs) in terms of high electronic conductivity and specific surface area, however, the low initial Coulombic efficiency and inferior cycle capability severely limit its application. Herein, oxygen-rich graphene vertically grown on 3D N-doped carbon foam (VGOG/3DNCF) is prepared via a super simple and scalable method, which just involves hydrogen-bond adsorption of graphene oxide with melamine sponge and subsequent two-step calcination. When VGOG/3DNCF is evaluated as anode for SIBs, the ultra-high oxygen content (16.4 at%) dominated by CO groups renders VGOG/3DNCF much more active sites for Na+ storage, and the vertical growth structure of graphene on 3D carbon foam can effectively reduce the restacking of graphene and promote the rapid migration of Na+. As a result, VGOG/3DNCF anode delivers extraordinary Na+ storage ability with outstanding reversible capability (508.6 mAh g−1 at 0.1 A g−1), superior rate performance (113.3 mAh g−1 at 5.0 A g−1) as well as remarkable cycle stability (329.3 mAh g−1 over 1000 cycles at 1.0 A g−1). The facile method together with the impressive electrochemical performances provide a new way to facilitate the application of graphene in SIBs.

Multi-scale CoNi nano-alloy/CoNi@C microsphere/3D macropores N-doped carbon foam composites: Lightweight and efficient electromagnetic wave absorption characteristics

Light carbon foam is considered to be one of the most promising candidate materials to provide excellent electromagnetic absorption properties in portable electronics and aerospace. However, it is still a challenge to prepare a wide-band, strong-absorbing carbon foam. In this work, melamine foam was used as a template and nitrogen source. We adopted the template method with simple operation and controllable microstructure, a new multi-scale CONi nanoalloy/CoNi@C microsphere/3D macropores porous N-doped carbon foam (CoNi/MF-P) composite material was prepared by simple hydrothermal and subsequent pyrolysis processes in an inert atmosphere as a microwave absorber. On the surface of the microstructure, CoNi nanocrystals (CoNi NCs) dispersed in the CoNi@C microspheres, and all the CoNi@C microspheres are uniformly attached to the edge of the carbon foam, and the complete melamine three-dimensional structure is retained. Combining the synergistic advantages of dielectric loss, magnetic loss and nano/micro/macropores porous structure, at a filling amount as low as 20%, it shows much higher electromagnetic wave (EMW) absorption performance than the carbon foam control group without CoNi NCs attached. It was observed that the effective absorption bandwidth of CoNi/MF-P4 covered the whole Ku-band frequency range of 11.93–18 (6.07) GHz, and the absorber thickness was only 1.6 mm. The minimum reflection loss (RLmin) of CoNi/MF-P5 was −60 dB at 3.98 GHz. At the same time, in the thickness range of 1.2–5 mm, a super broadband of 14 GHz (4–18 GHz) was also obtained. These results indicate that the interfacial interaction and synergy between CoNi NCs, CoNi@C and N-doped carbon foam play an important role in enhancing microwave absorbing properties.

Iron nanoparticles supported on N-doped carbon foam with honeycomb microstructure: An efficient potassium peroxymonosulfate activator for the degradation of fluoranthene in water and soil

A promising technology was developed for the remediation of fluoranthene (FLT) contaminated water and soil. Specifically, iron nanoparticles supported on N-doped carbon foam (Fe@CF-N) was synthesized by in-situ impregnation and a unique calcination process using pine cone as the precursor. The obtained Fe@CF-N was used as an activator of potassium peroxymonosulfate (PMS) to degrade FLT in water and soil. According to experimental results, Fe@CF-N had a three-dimensional network structure with a large specific surface area of 249.0 m2 g−1, displaying excellent catalytic performance. The maximum removal efficiency of FLT in water and soil reached 81.83% and 78.12% within 180 min, respectively. After four consecutive degradation cycles, the removal efficiency of FLT in water was still 55%. Electron spin resonance (ESR) measurements showed that hydroxyl radicals (·OH), sulfate radical (SO4−·) and 1O2 were the major reactive oxygen species (ROS). A series of low molecular weight intermediates were generated during the FLT degradation progress, such as C6H6O3 and C3H8O2. The effect of Fe@CF-N/PMS system on the phytotoxicity was evaluated via bioassay based on peas. The results indicated that seed germination rate and root shoot elongation of remediated soil by Fe@CF-N/PMS system were not significantly different from those of noncontaminated soil. This study provided a cost-effective remediation option for PAHs contaminated water and soil.

Graphene/TiO2 decorated N-doped carbon foam as 3D porous current collector for high loading sulfur cathode

The intrinsic contradiction between high loading and high capacity in sulfur cathode severely limits the commercial viability of Li-S batteries. Herein, Graphene/TiO2 decorated N-doped carbon foam (G/T-NF@CNT) is proposed as three-dimensional (3D) current collector for high loading sulfur cathode. This rationally designed current collector can not only provide enough space to accommodate active sulfur, but also endow sulfur cathode with strong polysulfide confining ability. More interestingly, 3D porous conductive structure has sufficient channels to realize rapid mass mobilization; meanwhile the high conductivity networks boost transfer kinetics of electrons. The electrochemical measurements demonstrate that G/T-NF@CNT/S cathode has a remarkable capacity of 788 mA h g−1 (5.83 mA h cm-2) at 0.1 A g−1 after 100 cycles with a high sulfur loading of 7.4 mg cm-2. This work provides new insights on multifunctional current collectors for thick sulfur cathodes in Li-S batteries.

Used dye adsorbent derived N-doped magnetic carbon foam with enhanced electromagnetic wave absorption performance

The increasing excess electromagnetic wave (EMW) radiations induce a serious pollution problem. The social requests urgently for EMW absorbing materials. Herein, as-prepared magnetic carbon foam (MCF) adsorbed RhB from the dye pollutant solutions. The used adsorbent was heat-treated at high temperature. Then, magnetic particle-decorated N-doped carbon foams (N-MCFs) were fabricated. N-doping content is determined by mass ratio of adsorbed RhB vs MCF. Excellent EMW absorption performance is achieved by optimizing impedance matching of N-MCFs. N-MCF-2 with a loading rate of 15% exhibits a lowest RLmin value of −60.46 dB with a Tm value as thin as only 1.70 mm. The corresponding effective bandwidth is 14.29 GHz and 13.79 GHz for −10 dB and −20 dB, covering the whole C band, X band and Ku band. For the absorbers with higher conductivities, the corresponding EMW absorption capacity can be further improved by reducing the loading rate. The distorted skeletons caused by N-doping induce the graphite lattice distortion and local density change of the carbon atomic state, significantly contributing to the magnetic moment. The enhanced dielectric loss by both defect polarization and dipole polarization effects, as well as the activated complex permeability by α-Fe/Fe3C/Fe2O3 composites decoration, are beneficial to EMW absorption.