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Chloride ion batteries (CIB) are considered to be one of the most promising energy storage devices. As cathode materials for CIBs, metal chlorides have many advantages, such as high theoretical energy density, abundant elemental resources and ideal discharge voltage plateau. However, the dissolution and huge volume change of metal chlorides during cycling lead to considerable short lifespan, which limits their potential application for CIBs. Herein, the bismuth chloride nanocrystal is confined in mesocellular carbon foam matrix by a new vacuum impregnation approach. The mesocellular carbon foam with large interconnected pores (15.7 or 23.2 nm) may buffer the large volume variation of bismuth chloride during charge and discharge, giving rise to significantly enhanced electrochemical performance. The as-prepared bismuth chloride@mesocellular carbon foam cathode delivered an initial discharge capacity of 298 mAh/g and a reversible capacity of 91 mAh/g after 60 cycles. In contrast, the pure bismuth chloride cathode almost cannot discharge after 30 cycles. This is the first report that the metal chloride cathode can achieve a prolonged cycling in CIBs.

This study developed a method to fabricate a surface-oxidized rigid carbon foam (ORCF) with hierarchical macro-nanoporous structure via KOH activation of the carbon foam with two kinds of macropores followed by HNO3 hydrothermal oxidation. The structures of the prepared ORCF were characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared (FTIR) spectra, X-ray photoelectron spectroscopy, and N2 adsorption-desorption analyzer. Results demonstrate that the ORCF possesses a fluffy and porous structure with rich oxygen-containing groups. There are numerous through-holes on its pore surfaces connected with two-level macropores forming hierarchical macroporous channels. Meanwhile, the ORCF remains a good bulk structure with a compression strength of 0.74 MPa at a bulk density of 0.09 g cm−3. Batch adsorption experiments for malachite green (MG) and Pb2+ were studied through the single variable method to investigate the effects of different initial conditions on its adsorption process. The ORCF has maximum adsorption capacities for MG and Pb2+ of 587.68 mg g−1 and 157.80 mg g−1 with high partition coefficients of 17.41 mg g−1 µM−1 and 14.86 mg g−1 µM−1, respectively. The experimental data are suitable for Langmuir isotherm and Pseudo-second-order kinetic models, which correspond to monolayer chemisorption. Thermodynamic analysis indicates that the adsorption process is spontaneous and endothermic. Moreover, the removal percentages of MG and Pb2+ by the ORCF could remain above 90% after five cycles, implying that the ORCF is an efficient adsorbent with good adsorption ability and cycling stability.

An efficient and facile approach to synthesize a bi-functional electrocatalyst via combining carbon foam with cobalt-centered zeolitic imidazolate framework (ZIF-67) is reported. The carbon foam was synthesized via dehydration of sugar utilizing zinc nitrate, forming Co3ZnC in the carbon matrix. To obtain Co hybridized and Co particles covered with carbon nanotubes embedded in a carbon matrix (Co-Zn-CNTs), physical mixing of both defines the critical point after pyrolysis. Higher content of N-related species and transition metal species in polyvalent states and well-grown multi-wall carbon nanotubes for charge transfer are achieved after the pyrolysis process. The obtained Co-Zn-CNTs catalyst was employed as cathode and anode for overall water splitting (HER and OER) and showed excellent performances. This development offers a low-cost and straightforward strategy to synthesize catalyst material for large-scale fuel cells and water splitting technologies. This development affords a precise method for effectively improving the electrocatalyst performance derived from the ZIF-67 precursor.

Grafting one-dimensional (1D) structure onto three-dimensional (3D) carbon foam is a practical and novel protocol to improve its microwave attenuation capability. Herein, a unique microwave absorber with NiCo2O4 nanoneedle grew on carbon foam (NCOCF) has been built via a combined approach of carbonization and hydrothermal treatment. The obtained NCOCF exhibit good impedance matching and excellent attenuation capability, which means that the microwave energy can be dissipated through conductive loss, interfacial polarization and multiple-scattering. These advantages result in the effective transformation of microwave energy to heat, thus yielding a remarkable microwave adsorption (with a thickness of 2.8 mm, the maximum reflection loss (RLmax) is −63.6 dB, and the effective absorption bandwidth (EAB) is as wide as 4.72 GHz with a thickness of 1.3 mm). The study would offer a strategy for development of the high-performance microwave absorber.

The paper presents a novel kind of carbon foam composites reinforced by chopped glass fibers. Microstructure, mechanical properties and thermal insulation of the composites have been investigated by scanning electron microscopy, universal testing machine and laser thermal constant analyzer, respectively. Results showed that carbon foam composites had a spherical and closed-cell structure; chopped glass fibers were uniformly distributed in the carbon matrix along different directions. The mechanical properties exhibited optimum with the 7% glass fiber additives, 11.27 MPa of shear strength, higher than that of pure carbon foams by as much as 111%. Compressive and shear fracture were both characterized by gradient brittleness. Many tiny open-pores existed in carbon foams with a certain amount of glass fiber additives, giving rise to the higher thermal conductivity. Nevertheless, carbon foam composites possessed good thermal insulation, 0.311 W·m−1·K−1 at room temperature, and 1.04 W·m−1·K−1 in 800 °C at the most.

Absorbing materials can convert electromagnetic wave (EMW) energy into heat and other energy and dissipate it. Carbon materials can attenuate EMW by generating large conduction losses due to their high conductivity. The introduction of low dielectric materials can improve impedance matching caused by high conductivity. However, the density of materials compounded with carbon materials is too large, which affects the overall density of composite materials. Therefore, this problem is solved by matching melamine foam with ZIF-67. As an ultra-light material, the melamine foam-based carbon material can significantly reduce the density of composite materials, and its developed three-dimensional structure can cause multiple scattering of EMW. The large specific surface area and evenly distributed metal oxides obtained after annealing of ZIF-67 can provide ultra-low-density carbon materials and abundant interfacial polarization to further attenuate EMW. So far, the methods of self-growing materials on the surface of melamine foam have not been reported. We prepared a 500 nm Co3O4 nanosheet/carbon foam (CF) composite material coated on the surface by a two-step method. The sample had a maximum reflection loss of −46.58 dB at 10.72 GHz, and an effective absorption bandwidth (EAB) of 5.4 GHz. This research provides a new idea for the growth of porous materials on the surface of melamine foam-based carbon materials.

Improved compressive strength and preeminent microwave absorbing properties are of great importance to meet the harsh requirements of the thermal environment. Herein, the SiC network reinforced SiO2 aerogel composites were synthesized via the carbonation, chemical vapor deposition, and sol-gel process using melamine sponge as the precursor and carbon foam as the structural template, followed by a heat treatment in the elevated temperature range of 300–1200 °C. The results showed that the compressive performance was significantly enhanced as a superior compressive response of 3.46 MPa at 9.49 % strain was obtained owning to the strengthened SiC skeleton wrapped by the SiO2 aerogel with the rising temperature. Besides, the composite after being warmed at 900 °C was provided with an efficient electromagnetic absorption capacity with a minimum reflection loss value of −55.38 dB at 16.56 GHz and a maximum effective frequency bandwidth of 8.16 GHz at 4.10 mm, resulting from the optimal attenuation constant as well as superior impedance matching ratio. Given the outstanding compressive strength and microwave absorbing characteristics, the aerogel composite has a good prospect in the complex electromagnetic fields.

Microwave absorption materials (MAMs), which can simultaneously show high reflection loss (RL) and broad effective absorbance band (EAB) at a thinner matching thickness, were meaningful to the settlement of current electromagnetic wave pollution. Herein, all-polymer derived carbon foam with unique molecular-level interpenetrating carbon network (ICN) heterojunction interface was constructed. The heterostructure was fabricated through carbonizing the molecular-level miscible interpenetrating polymer networks (IPN) of polyimide foam (PIF) and bismaleimide (BMI), while target heterojunction was proved through several characterizations. Benefitting from stronger polarization loss gene derived from countlessly molecular-level heterojunction interface of ICN, higher RL value could be realized at a thinner matching thickness. As a result, when only orthogonal polymerizing 5 wt% BMI with PIF, maximum RL value of corresponding carbon foam (CPIF-CBMI-5%) could achieve −72.8dB at the matching thickness of only 2.05 mm. In addition, the matching thicknesses of CPIF-CBMI-5% that covered the whole X band and Ku band were significantly decreased by 25% (3.75 mm to 2.8 mm) and 21% (2.6 mm to 2.05 mm) respectively, which was also superior to most foam materials that decorated by traditional loading or doping. Moreover, maximum EAB of CPIF-CBMI-5% could also achieved 6.2 GHz at 2.05 mm and its density was as low as 0.026 g/cm3.

In recent years, as a flexible electrode material, melamine foam has attracted more and more attention from researchers in the field of wearable energy storage devices. In addition, certain components are loaded on it to improve electrochemical performance and further promote its advantages. Here, we first carbonized commercial melamine foam in N2 atmosphere to form in situ doping and then used a simple hydro-thermal reaction to uniformly load MnO2 nanosheet arrays on its three-dimensional framework. For the resulting electrode material, the specific capacitance was as high as 230.3 F/g under the current density of 1 A/g. With the voltage window of 0–2.2 V, the energy density of the assembled quasi-solid supercapacitor reached 29.73 Wh/kg with the power density of 1636.9 W/kg, showing great electrochemistry performance and application prospects.

Lithium-ion capacitor (LIC) possesses multiple merits of Faradaic and capacitive behaviors and shows excellent energy and power densities. Herein, Co9S8 nanoparticles embedded on melamine foam derived three-dimensional (3D) carbon foam (M-Co9S8@NCF) was successfully constructed by an in-situ anchoring and annealing method. When the composite was used as a free-standing anode electrode of lithium-ion battery, volume expansion effect is relieved and reaction kinetic is significantly improved benefitting from the synergistic effect of unique 3D carbon network and ultrafine nanoparticles. Therefore, the M-Co9S8@NCF free-standing electrode delivers superior rate performance (1024 mAh g−1 at 0.1 A g−1 and 468 mAh g−1 at 2 A g−1) and stable cycling performance (617 mAh g−1 at 1 A g−1 for 500 cycles). Moreover, porous nitrogen-doped carbon foam (PNCF) was synthesized as the cathode of LIC. M-Co9S8@NCF//PNCF LIC device was then fabricated to combine the advantages of battery-type anode and supercapacitor-type cathode, which achieves a high energy density (166 Wh kg−1 at 182 W kg−1), high power density (83 Wh kg−1 at 7674 W kg−1) as well as satisfactory capacitance retention (83.5% at 5 A g−1 after 5000 cycles). This work offers a convenient method to construct metal sulfide-based free-standing electrode for the advanced lithium-ion storage devices.

The paper presents a systematic study of the formation of carbon nanofoam from sucrose by hydrothermal carbonization. It is shown that for the process temperature of 150 degrees C, carbonization is not a gradual process but rather occurs suddenly at a specific threshold time of 4.5 h. pH value and electrical conductivity (EC) of the sucrose solution were monitored during carbonization. In the first 4.5 h prior to carbonization, the sucrose solution shows a sharp drop from pH 7.8 to pH 2 and sharp increase of EC. From this point on the values of pH and EC remain approximately constant. After the 4.5 h threshold, we examined the evolution of mass yield, density and morphology of the resulting carbon nanofoam. The yield first shows a steep increase around 4.5 h and then a further gradual increase up to 38% at 54.6 h. The mass density just after the 4.5 h threshold is 0.28 g/cm(3) and decreases with process time to reach a constant value of 0.14 g/cm(3), between 20 and 54.6 h. This shows that desired conditions, such as low density and high yield, are obtained with sufficient process time below 5 h. Due to the release of intermediates of the conversion reaction into the sucrose solution, both pH and EC were found to be excellent indicators for the progression of hydrothermal carbonization.

The development of non-precious metal catalysts to replace scarce and costly Pt-based catalysts is crucial for oxygen reduction reaction (ORR), which involves various electrochemical energy conversions, such as fuel cells and metal-air batteries. However, it is still a challenge to devise a simpler method to obtain high-performance non-noble metal catalyst, which can be used for large-scale production. Herein, Cu and N co-doped mesocellular carbon foam (n-Cu/NC) has been developed by strong electrostatic adsorption (SEA) method, which inherits the original morphology of carbon foam, exhibiting high ORR performance with a half-wave potential of 0.825 V vs. RHE and excellent long-term durability. The outstanding performance of n-Cu/NC is attributed to the high specific surface area, hierarchical porous carbon matrix doped by multiple N atoms and uniform Cu2O/CuO active sites induced by the SEA method. The strategy of SEA method is applied to the preparation of carbon-supported catalysts, which shows great potential in the design and large-scale production of M and N co-doped carbon materials.

Recently, metal organic frameworks (MOFs) derived porous carbon (PC) was integrated with phase change materials (PCMs) to form composite with enhanced thermal conductivity and stability. However, the aggregation of PC particles during carbonization results in low utilization of supporting material and decrease of loading capacity. In this research, Cu foam monolith was decorated with highly dense nanorods (NRs) to provide numerous attached sites for PC particles. Stearic acid (SA) was then filled into the PC/NRs support to prepare a SA-based hierarchical composite (SA@PC/NRs). The hierarchical composite exhibits enhanced loading capacity (42%) and thermal conductivity (0.81W/mK) than that of referent SA@PC/CF and SA@PC, as well as improved energy storage efficiency, durability and shape-stability. The hierarchical composite PCM allows light-driven thermal energy storage with high conversion and storage efficiency, indicating its potential applications in solar-energy utilization and storage.

MXene is a neoteric type of bidimensional (2D) transition metal carbide/nitride with broad application prospects, in particular with electrochemical energy storage. The electrochemical performance of MXene is unsatisfactory because it is easy to stack resulting in the difficulty of electrolyte penetration and ion transport. In this study, the cobaltous sulfide-modified 3D MXene/N-doped carbon foam (CoS@MXene/CF) hybrid aerogel is projected and manufactured via simple in situ growth and thermal annealing strategies. The capacitance of the as-fabricated 300-CMC-31:1 electrode material reaches 250 F g-1 (1 A g-1), which is obviously higher than those of MXene, CoS@CF, 400-CMC-31:1, 300-CMC-10:1, 300-CMC-50:1, CF, and MXene/CF electrode materials. Moreover, it can hold 97.5% of the original capacitance after 10,000 cycles and the internal resistance (Rs) is only 0.50 Ω. A green bulb can be lit by two all-solid asymmetric supercapacitors installed in series. The prepared CoS@MXene/CF hybrid aerogel exhibits promising potential for practical application in energy storage areas.

Herein, we present a stepwise approach for constructing 3-dimensional porous carbon foam pretreated via glutaraldehyde cross-linking and decorated with highly dispersed molybdenum carbide (CF-Glu-Mo) or Co-doped FeNi carbonate hydroxide (CF-Glu-CoFeNi), which is structurally derived from the initial chitosan hydrogel. The as-prepared CF-Glu-Mo and CF-Glu-CoFeNi can act as mono-functional electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. In 1.0 M KOH, CF-Glu-Mo exhibits a small overpotential of 88 mV with a low Tafel slope of 56 mV dec−1 under the working condition of 10 mA cm−2 for HER, and CF-Glu-CoFeNi requires an overpotential of 290 mV for OER to reach a current density of 50 mA cm−2, accompanied by a low Tafel slope of 115 mV dec−1. In this case, these integrated electrodes derived from the robust interconnection between the electrocatalyst and the chitosan hydrogel derived carbon foam make the whole water decomposition behavior more direct and efficient, which is reasonably attributed to hierarchically porous nanostructures and intrinsically high conductivity. The full electrolyzer assembled with carbon cloth (CC) of CF-Glu-Mo/CC||CF-Glu-CoFeNi/CC can drive full alkaline water splitting by applying a voltage of 1.65 V at a catalytic current of 10 mA cm−2 for 24 h. Meanwhile, this work provides a feasible approach for the development of efficient water splitting electrocatalysts through the rational design and regulation of heterogeneous interfaces and nanostructures.

Highly conductive and elastic three-dimensional (3D) porous carbon materials are ideal platforms to fabricate electrodes for high-performance compressible supercapacitors. Herein, a robust, highly conductive, and elastic carbon foam (CF) hybrid material is reported, which is fabricated by integrating cellulose nanofiber/multiwalled carbon nanotube (CNF/MWCNT) aerogel sheets with a melamine sponge (MS), followed by carbonization. The carbonized CNF/MWCNT aerogel sheets contribute to the high conductivity and specific surface area of the CF, and the 3D network-like skeleton derived from the carbonization of the MS enhances the elasticity and stability of the CF. More importantly, the CF possesses good scalability, allowing the introduction of electroactive materials such as polypyrrole (PPy) and Fe3O4 to fabricate high-performance compressible PPy–CF and Fe3O4–CF electrodes. Moreover, an assembled PPy–CF//Fe3O4–CF device shows reversible charging–discharging at a voltage of 1.6 V and demonstrates a high specific capacitance (172.5 F/g) and an outstanding energy density (59.9 W h/kg). The device exhibits capacitance retention rates reaching 98.3% and stable energy storage characteristics even under different degrees of compressive deformation. This study offers a scalable strategy for fabricating high-performance compressible supercapacitors, thereby providing a new means of satisfying the energy storage needs of portable electronic devices that are prone to deformation.

Oxidized carbon foam (oxidized CF) was prepared by using a facile chemical oxidation treatment at relatively low temperature of 450 °C and applied to capture uranyl cation [U(VI)] from aqueous solutions. The effects of pH, contact time, initial U(VI) concentration, and temperature on the U(VI) absorption performance of oxidized CF were investigated by batch experiments. The oxidized CF was illustrated to exhibit fast sorption kinetics (92% removal within 15 min and 98% removal in 2 h) and high sorption capacity (305.77 mg g-1 at pH 5) toward U(VI). Integrated analyses combining energy-dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy were applied on the U(VI)-loaded oxidized CF, showing the introduction of carboxyl groups as U(VI) sorption sites on the surface of CF after oxidation treatment. Furthermore, extended X-ray absorption fine structure spectroscopy was employed to identify the binding modes of U(VI) indicating that each UO22+ cation is coordinated with one or two carboxyl groups on the equatorial plane. Notably, the low content of U(VI) in wastewater can be efficiently immobilized by the oxidized CF, and the immobilized U(VI) can be further concentrated and converted into Na2U2O7 or U3O8 by a simple sintering step. These findings presented in this work suggest the potential of using oxidized CF for further treatment of low concentration wastewater containing U(VI).

White wastes (unseparated plastics, face masks, textiles, etc.) pose a serious challenge to sustainable human development and the ecosystem and have recently been exacerbated due to the surge in plastic usage and medical wastes from COVID-19. Current recycling methods such as chemical recycling, mechanical recycling, and incineration require either pre-sorting and washing or releasing CO2. In this work, a carbon foam microwave plasma process is developed, utilizing plasma discharge to generate surface temperatures exceeding ∼3000 K in a N2 atmosphere, to convert unsorted white wastes into gases (H2, CO, C2H4, C3H6, CH4, etc.) and small amounts of inorganic minerals and solid carbon, which can be buried as artificial "coal". This process is self-perpetuating, as the new solid carbon asperities grafted onto the foam's surface actually increase the plasma discharge efficiency over time. This process has been characterized by in situ optical probes and infrared sensors and optimized to handle most of the forms of white waste without the need for pre-sorting or washing. Thermal measurement and modeling show that in a flowing reactor, the device can achieve locally extremely high temperatures, but the container wall will still be cold and can be made with cheap materials, and thus, a miniaturized waste incinerator is possible that also takes advantage of intermittent renewable electricity.

Assembling active materials on flexible conductive matrixes for fabricating high-rate, self-supported and durable anodes is essential for the development of high-power flexible lithium-ion batteries. In this study, we report an efficient combinational strategy for producing hybrid composites (TNO@MCF) of Ti2Nb10O29 (TNO) anchored on melamine carbon foam (MCF) via a hydrothermal method. The N-doped MCF not only showed good electronic conductivity and flexibility, but also improved the ion transport performance of the composites. The TNO@MCF electrode exhibited remarkably high rate capacities (327 mA h g−1 at 1 C, and 205 mA h g−1 at 40 C) and excellent cycling stability with a high capacity retention of 81.4% after 1000 cycles at 10 C. After 100 compression-rebound cycles, the TNO@MCF electrode showed a reversible capacity of 315 mA h g−1 at 1 C and exhibited a capacity retention of 72.3% for 1000 cycles at 10 C. This compressible structure design could provide guidelines for manufacture of other flexible electrodes for energy storage devices.

The development of next-generation lithium metal batteries (LMBs) has been chronically hindered by uncontrollable dendrite growth and infinite dimension change of metal Li. Even though the porous carbon skeletons have been deemed as effective hosting materials to prepare low-stress Li metal anode (LMA), the lithiophobic feature and poor spatial regulation for Li nucleation/growth of carbon skeletons render the achievement of high-stable LMA to be challenging. Herein, vertical-aligned SnS2 nanosheet arrays (SnS2 NSA) with intrinsic lithiophilic nature, endowed by in situ formed Li13Sn5 via the alloying reaction of SnS2, are uniformly decorated on highly flexible carbon foam (SnS2 NSA@CF) to overcome the encountered issues of ordinary carbon skeletons. The vertical-aligned SnS2 nanosheet offers enriched lithiophilic surface area, thereby guiding the thin Li-nuclei layer uniformly deposited on nanosheet. Moreover, the continuous Li growth is proceeded on the initial Li-nuclei layer and spatially confined into the nanochannels of nanoarray to eliminate the volume change of LMA. The well-defined nanochannel effectively reduces the local current density and provides open spacing for quick charge transfer kinetics. Accordingly, the sustainable Li utilization with high Coulombic efficiency and highly stable Li plating/stripping with low polarization is achieved, shedding light on the feasibility of SnS2 NSA for dendrite-free LMA.

The lithium–sulfur (Li–S) battery is an ideal electrochemical energy storage system owing to the high theoretical energy density and acceptable cost of finance and the environment. However, some di...

The simple and low-cost supercapacitor preparation strategy has received great attention at present. In our work, the MnO2 nanosheets were equably grown on carbon foam by electrodeposition to synthesize electrode. The carbon foam (CF) is a three-dimensional (3D) conductive skeleton that guarantees the rapid transfer of ions and electrons. An appropriate amount of MnO2 nanosheets provide excellent pseudocapacitance properties. The composite material reaches the highest specific capacitance of 365 F g−1 at 1 A g−1 and the cycling test shows capacitance retention of 87.7% over 5000 cycles at a current density of 10 A g−1 in a three-electrode system. Meanwhile, the device revealed a maximum energy density of 22.2 Wh kg−1 at a power density of 1000 W kg−1. Two assembled supercapacitors were enough to light up a timer and the material has a certain practical value.

Three-dimensional (3D) carbon-based materials have attracted growing attention in the field of electromagnetic wave absorption applications. However, their high conductivity results in high dielectric constant, leading to impedance mismatching, and this characteristic finally weakens their electromagnetic wave absorption performance. In this work, 3D carbon foam (3DCF) was successfully prepared by calcining the melamine foam as the carbon framework precursor under N2 atmosphere. Subsequently, 1T-2H MoS2 nanosheets were uniformly assembled on the surface of the 3DCF skeleton through a solvothermal process. The diameter of the 3DCF skeleton was about 1 μm and the thickness of the 1T-2H MoS2 on the surface was about 150 nm. The 3D network brings in many advantages for microwave attenuation, including numerous conductive pathways, excellent impedance matching and multi-polarization processes. The composites exhibited a maximum reflection loss (RLmax) of −45.88 dB at 10.2 GHz with the thickness of 2.2 mm, and the effective absorbing bandwidth (EAB) was as wide as 5.68 GHz, implying their superb microwave absorption behavior. This work is believed to offer a strategy for the design of efficient 3D electromagnetic wave absorbers with low density in the future.

Searching for ultralight microwave absorber with good heat-insulating property is highly desirable to fulfill the technical requirement of modern society. Herein, the two-dimension (2D) graphene-like porous carbon nanosheets (GPCN) derived from the waste pomelo peel were developed. The preparation is performed by a facile hydrothermal process with synergistic usage of HAc and H2O2. Interestingly, the thickness and porosity of GPCN can be readily regulated by adjusting addition amount of the reagents. The related synthetic mechanism is investigated in depth. Compared with traditional graphene, the fabrication strategy of GPCN possesses many advantages, such as low cost, high yield and ease of production. The results show that GPCN presents superior thermal insulation and microwave absorption properties. The heat-insulating property is comparable to commercial products, e.g. polyurethanes (PU), nickel foam (NF), carbon foam (CF). The strong microwave absorption intensity of −56.4 dB and bandwidth of 6.4 GHz is achieved under ultralow filling ratio of 4 wt%. Moreover, the density of assembled 3D macroscopically product is merely 0.01 g/cm−3. The excellent performance should be attributed to the unique 2D morphology and high porosity of GPCN. Our work paves a new way for developing porous carbon nanosheet from sustainable biomass as heat-insulating ultralight microwave absorber.

Three-dimensional (3D) carbon foams (CF) embedded with CuNi alloy nanoparticles have been constructed for electromagnetic wave absorption application. In the synthetic procedure, Ni2+ and Cu2+ were firstly adsorbed into the melamine foam (MF) to form Ni2+-Cu2+/MF composites, which were then subject to the pyrolysis treatment, resulting in the production of mesoporous CuNi alloy/CF. The texture characterizations indicate that CuNi alloy nanoparticles whose size distribution was 20–600 nm were embedded on the surface of the CF. Other than previous carbon structures, the CuNi/CF with CuNi alloy nanoparticles evenly distributed into the 3D carbon matrix inherits the characteristic of the 3D structured N-rich MF, which induces masses of dipole polarization, interfacial polarization and electromagnetic wave scattering. The CuNi11 exhibits excellent electromagnetic wave absorption performance with the reflection loss (RL) of −50.20 dB at a thin thickness of 1.6 mm. This work highlights the effect of metal compositions on the electromagnetic wave absorption performance and provides an environmentally friendly, low cost and easy-to-large-scale-preparation approach for the design of metal alloy/CF electromagnetic wave absorbers.

As sulfosalicylic acid (SUA) is extensively used as a pharmaceutical product, discharge of SUA into the environment becomes an emerging environmental issue because of its low bio-degradability. Thus, SO4 −-based advanced oxidation processes have been proposed for degrading SUA because of many advantages of SO4 −. As Oxone represents a dominant reagent for producing SO4 −, and Co is the most capable metal for activating Oxone to generate SO4 −, it is critical to develop an effective but easy-to-use Co-based catalysts for Oxone activation to degrade SUA. Herein, a 3D hierarchical catalyst is specially created by decorating Co3O4 nanocubes (NCs) on macroscale nitrogen-doped carbon form (NCF). This Co3O4-decorated NCF (CONCF) is free-standing, macroscale and even squeezable to exhibit interesting and versatile features. More importantly, CONCF consists of Co3O4 NCs evenly distributed on NCF without aggregation. The NCF not only serves as a support for Co3O4 NCs but also offers additional active sites to synergistically enhance catalytic activities towards Oxone activation. Therefore, CONCF exhibits a higher catalytic activity than the conventional Co3O4 nanoparticles for activating Oxone to fully eliminate SUA in 30 min with a rate constant of 0.142 min−1. CONCF exhibits a much lower Ea value of SUA degradation (35.2 kJ/mol) than reported values, and stable catalytic activities over multi-cyclic degradation of SUA. The mechanism of SUA degradation is also explored, and degradation intermediates of SUA degradation are identified to provide a possible pathway of SUA degradation. These features validate that CONCF is certainly a promising 3D hierarchical catalyst for enhanced Oxone activation to degrade SUA. The findings obtained here are also insightful to develop efficient heterogeneous Oxone-activating catalysts for eliminating emerging contaminants.

Despite great progress of lithium-sulfur (Li-S) battery performance at the laboratory-level, both key parameters and challenges at cell scales to achieve practical high energy density require high-sulfur-loading cathodes and lean electrolytes. Herein, a novel carbon foam integrated by hollow carbon bubble nanoreactors with ultrahigh pore volume of 6.9 cm3·g−1 is meticulously designed for ultrahigh sulfur content up to 96 wt.%. Tailoring polysulfide trapping and ion/electron transport kinetics during the charge-discharge process can be achieved by adjusting the wall thickness of hollow carbon bubbles. And a further in-depth understanding of electrochemical reaction mechanism for the cathode is impelled by the in-situ Raman spectroscopy. As a result, the as-prepared cathode delivers high specific capacitances of 1,269 and 695 mAh·g−1 at 0.1 and 5 C, respectively. Furthermore, Li-S pouch cells with high areal sulfur loading of 6.9 mg·cm−2 yield exceptional practical energy density of 382 Wh·kg−1 under lean electrolyte of 3.5 µL·mg−1, which demonstrates the great potential for realistic high-energy Li-S batteries.

The issue of bonding formation in liquid metal/open-celled carbon foam (Cof) systems was examined, taking into account the practical aspects of the synthesis of a new type of Mg-C metal material composite. The problem is complex due to the strong oxidation and intense evaporation of liquid magnesium, as well as the 3D geometry of the carbon component, where metal transport occurred through the foam cells’ windows. Laboratory experiments performed at 700°C in ceramic crucibles showed that spontaneous carbon foam infiltration by liquid metal is impossible under the applied conditions, either in an air atmosphere coupled with flux protection or under argon protection. Comparative tests performed in a UHV chamber filled with static pure Ar by a sessile drop method, coupled with non-contact heating and capillary purification at a test temperature of 700°C directly in the UHV chamber, showed non-wetting behavior of the Mg/Cof couple with a correspondingly high contact angle of about 135°. The graphite capillary was then moved down, the liquid drop being slightly pressed into the foam, but these changes did not induce effective foam penetration. Despite the short contact time for the sessile drop test under an argon atmosphere, SEM+WDS analysis of the solidified Mg/Cof couple revealed the formation of an MgO interlayer at the interface, with a thickness of approx. 1 µm. The experimentally demonstrated presence of oxygen in the carbon foam sample, both before and after its contact with magnesium, points to oxide-type bonding being established between Mg and Cof. This observation is in a good agreement with previous reports on the interface characterization of magnesium matrix composites reinforced with glassy carbon materials and carbon fibers by stir casting and pressure infiltration. Based on the findings of this study, a general structural scheme of the bonding process between carbon foam and liquid magnesium, as an important stage in the syntheses of Mg-C composites, was proposed.

A facile and single-step nickel oxide-dispersed in situ grown 3-D graphitic forest engrained carbon foam (NiO-CNF-CF)-based electrode was fabricated for high-performance microbial fuel cells (MFCs). The metal oxide, graphitic contents, biocompatibility, stability and large surface area available in the material for biofilm formation rendered the prepared electrode competent for wastewater treatment and bioenergy (0.79 V and 1.955 W m-2) generation with a coulombic efficiency of 85.66%.

Compressible materials have received great attention due to potential applications for energy storage and sensors in special cases. In the present work, reduced graphene oxide (RGO) was coated on carbon foam, and polyaniline (PANI) nanorods were grown on it to synthesize a compressible ternary composite. In this scenario, carbon foam was carbonized and used as a three-dimensional conductive and compressible framework; RGO nanosheets were the growth carrier of PANI which provided high pseudocapacitance. Due to the conservation of elasticity after carbonization, the device can be fully restored after compression strain and the electrochemical performance remained stable. As electrodes of a supercapacitor, a specific capacitance of 533 F g−1 was achieved in a two-electrode configuration. After 2000 charge–discharge cycles at 10 A g−1, 86.7% of the initial capacitance was retained. Meanwhile, this material as a piezoresistive pressure sensor has high sensitivity to 13.6 kPa and can be used to detect continuous stress variation. The presented composite material with excellent piezoresistive sensitivity and electrochemical performance shows broad prospects in the field of wearable devices.

Hydrogen is now becoming a great source of efficient and clean energy to cope with the world's energy problem. The electrochemical hydrogen evolution reaction (HER) is a non-polluting way to get large quantities of hydrogen. To accelerate the HER, it is very important to develop catalysts with a high HER performance. In this report, a CoS2-porous carbon foam (CoS2-CF-X, X = 1, 2, 3, and 4) catalyst for the HER was obtained using a hydrothermal method. Porous carbon foam provided a vehicle for rapid electron transport for CoS2, which made the prepared catalyst exhibit an excellent catalytic activity of the HER with a small overpotential of 121 mV at a current density of 10 mA cm−2; meanwhile the Tafel slope is 68 mV dec−1. In addition, the CoS2-CF catalyst displayed an excellent cyclic stability after 4000 cycles.

Rational design of the microstructure of a multifunctional electromagnetic wave absorber is a greatly promising route to establish convenient performance regulation and to satisfy complex application conditions. In this work, the proposed material for the absorber is a compressible carbonated reduced graphene oxide/Fe3O4 (C-rGO/Fe3O4) carbon foam with hollow microspheres and a concave–convex microstructure. Its unique porous structure can strengthen the multiple reflections of electromagnetic waves and improve the system's mechanical properties. The C-rGO/Fe3O4 carbon foam possesses excellent comprehensive electromagnetic wave absorption performance (reflection loss (RL) value of −57.50 dB and effective bandwidth of 6.72 GHz) and exhibits convenient RL value regulation (when varying compressive strains). The RL value of the carbon foam can be adjusted within the absorption range of RL ≤ −20 dB or switched between ≤−20 dB and RL ≤ −10 dB, exhibiting a smart function-tunable or function-switchable feature. Moreover, the compressible carbon foam also exhibits excellent fatigue durability and can be used to monitor human physiological signals. This provides a promising platform for practical applications in adjustable electromagnetic wave absorption; the material can also be used for wearable electronics.

A three-dimensional carbon foam (CF)-based asymmetric planar micro-supercapacitor is fabricated by the direct spray patterning of active materials on an array of interdigital electrodes. The solid-state asymmetric micro-supercapacitor comprises the CF network with pseudocapacitive metal oxides (manganese oxide (MnO), iron oxide (Fe2O3)), where CF-MnO composite as a positive electrode, and CF-Fe2O3 as negative electrode for superior electrochemical performance. The micro-supercapacitor, CF-MnO//CF-Fe2O3, attains an ultrahigh supercapacitance of 18.4 mF cm−2 (2326.8 mF cm−3) at a scan rate of 5 mV s−1. A wider potential window of 1.4 V is achieved with a high energy density of 5 μW h cm−2. The excellent cyclic stability is confirmed by 86.1% capacitance retention after 10 000 electrochemical cycles.

Developing high energy density lithium-sulfur (Li–S) batteries mainly relies on the design of the electrode matrix which can accommodate high sulfur loading and still remain high utilization of active materials. Herein, a 3D hierarchical graphitic carbon foam supported graphene@Mo2C (GCF-G@Mo2C) heterostructure is introduced as a freestanding electrode for Li–S batteries with a facile and cost-effective method. The N-doped carbon foam wrapped by graphene sheets with agaric-like porous structure could promote fast electron and ion transport, meanwhile effectively anchor the polysulfides through physical confinement and chemical adsorption by strongly polar-polar interactions. More importantly, the Mo2C nanoparticles can act as the chemical anchoring center to provide strong polysulfide adsorption, as testified by experimental data and first-principle calculations. Moreover, the catalytic effect of Mo2C also accelerates the redox kinetics of polysulfide conversion, contributing to enhanced rate performance. As a result, the cell with GCF-G@Mo2C displays an initial capacity as high as 862 mAh g−1 and a retained capacity of 597 mAh g−1 after 600 cycles with only 0.051% capacity fade per cycle at 1C rate, presenting good cycling stability. In addition, the GCF-G@Mo2C substrate with high sulfur content (70 ​wt%) and sulfur loading (10.5 ​mg ​cm−2) achieves an ultra-high areal capacity of 12.6 mAh cm−2 at 0.1 ​C, offering a competitive cathode for high-performance Li–S batteries.

In order to obtain high-performance thermal protection materials, a novel all-carbon triple-layer structure was designed by orderly combining high thermal conductivity carbon/carbon composites (HTC-C/C), polyacrylonitrile-based carbon fiber reinforced composites (PAN-C/C) and carbon foam. During exposure to the oxyacetylene torch, compared with the multi-layer structure made of PAN-C/C and carbon foam, the maximum surface temperature of the triple-layer structure was lowered from 2348 °C to 2215 °C, and the mass ablation rate was reduced by 90.0%, attributed to the excellent heat-dissipation performance and the higher anti-oxidation property of HTC-C/C. When compared with the multi-layer structure composed of HTC-C/C and PAN-C/C, the back surface temperature of the triple-layer structure is further decreased by 700 °C, proving the effective thermal insulation of carbon foam; meanwhile, by isolating the air structure of the intermediate layer made of PAN-C/C was protected from oxidation.

The applicability of a new carbon material—carbon foam with a cellular structure synthesized from the pyrolysis products of hydrocarbon gases—as a catalyst support was demonstrated. The modification of the carbon foam by the deposition of nanoglobular carbon particles on its surface made it possible to obtain a nonporous material with a specific surface area of

Many industries store hazardous liquid waste in open ponds prior to treatment or as a means of disposal. In some cases, these ponds may present a hazard to migrating waterfowl. Present methods of deterring birds, such as plastic ‘shade balls’, reduce evaporation, making them ineffective where evaporation is desirable. To combat this effect, we applied photothermal materials to high-density polyethylene (HDPE) containers to create “photothermal floats”, which absorb solar irradiation and promote, rather than deter, evaporation. In this study, inexpensive materials (granular activated carbon, fiberglass, and carbon air filters) were coated onto HDPE containers. Carbon foam, a buoyant material, was used alone. These materials were tested for their effects on evaporation rates in a laboratory environment at low light intensities (150 W∙m−2). Granular activated carbon (GAC) displayed the largest improvement in evaporative performance, increasing the evaporation rate by 64 ± 7% compared to a control with standing water and 199 ± 7% compared to uncoated HDPE. Materials were characterized using scanning electron microscopy, specific surface area analysis, water retention analysis, contact angle goniometry, and reflectance. We observed significant and unexpected differences between materials in all parameters and their connections to measured evaporation rates. These novel and inexpensive material combinations may provide a new tool for water managers who need to maintain or improve evaporation rates while deterring waterfowl.

A rational strategy is developed to prepare a nanocomposite with 0D/3D architecture. The composite containing Mn3O4 nanoparticles (0D) and carbon foam (3D) could be applied as an electrode material...

In this work a facile synthesis method is adopted to demonstrate the large mesoporous carbon foam. The green foam was made from fine flour, yeast and xanthan gum were used as a base, leaving agent and binding agent respectively. After the blowing process the foam is placed in a tube furnace for pyrolysis. Finally, the foam heat absorption properties as well as heat retarding properties were established in contrast to traditional aluminum-based heat sink as well as K23 (aluminosilicate refractory) brick.