Carbon Sponge Research Articles

Extreme biomimetics: Preservation of molecular detail in centimeter-scale samples of biological meshes laid down by sponges.

Fabrication of biomimetic materials and scaffolds is usually a micro- or even nanoscale process; however, most testing and all manufacturing require larger-scale synthesis of nanoscale features. Here, we propose the utilization of naturally prefabricated three-dimensional (3D) spongin scaffolds that preserve molecular detail across centimeter-scale samples. The fine-scale structure of this collagenous resource is stable at temperatures of up to 1200°C and can produce up to 4 × 10-cm-large 3D microfibrous and nanoporous turbostratic graphite. Our findings highlight the fact that this turbostratic graphite is exceptional at preserving the nanostructural features typical for triple-helix collagen. The resulting carbon sponge resembles the shape and unique microarchitecture of the original spongin scaffold. Copper electroplating of the obtained composite leads to a hybrid material with excellent catalytic performance with respect to the reduction of p-nitrophenol in both freshwater and marine environments.

Ultralight Three-Dimensional Hierarchical Cobalt Nanocrystals/N-Doped CNTs/Carbon Sponge Composites with a Hollow Skeleton toward Superior Microwave Absorption.

It is extremely desirable but remains greatly challenging to obtain high-performance microwave absorption (MA) materials with thin thickness, lightweight, wide frequency bandwidth, and strong absorption by facile and low-cost preparing methods. In this work, by utilizing an inexpensively commercial melamine-formaldehyde sponge (MFS) as a template for growth of a Co-based metal-organic framework (ZIF-67) and subsequently carbonizing this ZIF-67-decorated MFS in a nitrogen atmosphere, an ultralight (8 mg cm-3), three-dimensional hybrid carbon sponge composite with a hierarchical micro/nanostructure and hollow skeleton is successfully prepared to acquire excellent MA performances for the first time. The as-obtained composite consisted of interconnected carbon microtubes as a skeleton, intertwined N-doped carbon nanotubes (CNTs) grew on the outer surface of the carbon microtubes, and metallic Co nanocrystals encapsulated at the tips of the CNTs. Benefiting from the unique architecture and hierarchical composite which contribute to a good conductive network, moderate magnetic loss, strong matched impedance, and multiple polarization, the composite (Co/CNTs/CS) exhibited a minimum reflection loss (RL) of -51.2 dB and an effective absorption bandwidth (EAB, RL < -10 dB) of 4.1 GHz with a matching thickness of 2.2 mm at a filler loading of as low as 10 wt % in paraffin wax. Even with the thickness of 1.6 mm or at the filler loading of 5 wt %, the composites can also gain the low minimum RL value of -30.9 or -17.9 dB, respectively. In addition, the largest EAB was 5.4 GHz at the thickness of 2.0 mm, and the tunable EAB can be achieved in the range of 3.6-18 GHz, covering 90% of the measured frequency range via adjusting the absorber thickness between 1 and 5.5 mm. The results offer new insights for designing advanced microwave absorbers with lightweight, thin thickness, strong RL, and wide absorption frequency range.

Testing the relationship between microbiome composition and flux of carbon and nutrients in Caribbean coral reef sponges

BackgroundSponges are important suspension-feeding members of reef communities, with the collective capacity to overturn the entire water column on shallow Caribbean reefs every day. The sponge-loop hypothesis suggests that sponges take up dissolved organic carbon (DOC) and, via assimilation and shedding of cells, return carbon to the reef ecosystem as particulate organic carbon (POC). Sponges host complex microbial communities within their tissues that may play a role in carbon and nutrient cycling within the sponge holobiont. To investigate this relationship, we paired microbial community characterization (16S rRNA analysis, Illumina Mi-Seq platform) with carbon (DOC, POC) and nutrient (PO4, NOx, NH4) flux data (specific filtration rate) for 10 common Caribbean sponge species at two distant sites (Florida Keys vs. Belize, ~ 1203 km apart).ResultsDistance-based linear modeling revealed weak relationships overall between symbiont structure and carbon and nutrient flux, suggesting that the observed differences in POC, DOC, PO4, and NOx flux among sponges are not caused by variations in the composition of symbiont communities. In contrast, significant correlations between symbiont structure and NH4 flux occurred consistently across the dataset. Further, several individual symbiont taxa (OTUs) exhibited relative abundances that correlated with NH4 flux, including one OTU affiliated with the ammonia-oxidizing genus Cenarchaeum.ConclusionsCombined, these results indicate that microbiome structure is uncoupled from sponge carbon cycling and does not explain variation in DOC uptake among Caribbean coral reef sponges. Accordingly, differential DOC assimilation by sponge cells or stable microbiome components may ultimately drive carbon flux in the sponge holobiont.

Analisis Kinetik Penghasilan Biohidrogen dari Proses Fermentasi Menggunakan Bakteria Penghasilan Hidrogen ke atas Span Karbon Aktif daripada Sisa Nanas

Pineapple residues are one of potential biomass feedstock for biohydrogen production. The most convenient way to produce biohydrogen from pineapple residual is through fermentation proses. The process is environmentally friendly and consumes low energy, but generally the process has low yield production. Various strategies can be used to increase production, including the use of immobilized cells in fermentation. The performance of the process can be explained as realistically as possible by the appropriate kinetic model. In this work, a kinetic analysis on fermentative biohydrogen production using different hydrogenproducing bacteria immobilized onto activated carbon sponge has been performed. The performance of cumulative and biohydrogen production rate were assessed using modified Gompertz equation via Excel solver application. All fermentation processes were carried out at a condition of initial pH 7 and temperature of 32 ± 1°C, with 30% v/v inoculum of working volume in batch process. Three different hydrogen-producing bacteria were used, namely Escherichia coli, Enterobacter aerogenes and Clostridium sporogenes, were immobilized onto activated carbon sponge and in free cell form as comparison. Based on best fitting curve results on the cumulative biohydrogen production, it was found that modified Gompertz equation were fitted well with all the experimental results of all regression values, R2 were greater than 0.9. This study also presented that E. aerogenes and C. sporogenes able to produce better result compared to E.coli in term of production of biohydrogen The modified Gompertz equation would be useful for further analysis of biohydrogen production performance of selected hydrogen-producing bacteria culture immobilized onto activated sponge from pineapple residues.

ZIF-derived wrinkled Co3O4 polyhedra supported on 3D macroporous carbon sponge for supercapacitor electrode

Abstract Co3O4/melamine-derived carbon sponge (MCS) nanocomposite in which wrinkled ball-in-dodecahedral Co3O4 nanoparticles derived from ZIF-67 were homogeneously dispersed on the interconnected MSC was fabricated via a simple immersion and thermolysis route. As-prepared ultralight Co3O4/MCS possessed mechanically robust characteristic and unique 3D macroporous framework anchored with corrugated Co3O4 dodecahedra. Utilized as a pseudocapacitor electrode, Co3O4/MCS hybrid exhibited a great specific capacitance of 1409.5 F g−1 at the current density of 0.5 A g−1 and excellent long-term cycling stability of 93.2% after 1000 charge/discharge cycles, which might be ascribed to the synergistic effect of the inherent high redox activity from Co3O4 polyhedra combined with excellent electrical conductivity of MCS. This work demonstrates that tunable structure design and rational morphology control are efficient approaches for manufacturing novel electrode materials with extraordinary electrochemical performance.

Metal Sulfide‐Decorated Carbon Sponge as a Highly Efficient Electrocatalyst and Absorbant for Polysulfide in High‐Loading Li2S Batteries

AbstractOwing to its high theoretical specific capacity (1166 mA h g−1) and particularly its advantage to be paired with a lithium‐metal‐free anode, lithium sulfide (Li2S) is regarded as a much safer cathode for next‐generation advanced lithium–sulfur (Li–S) batteries. However, the low conductivity of Li2S and particularly the severe “polysulfide shuttle” of lithium polysulfide (LiPS) dramatically hinder their practical application in Li–S batteries. To address such issues, herein a bifuctional 3D metal sulfide‐decorated carbon sponge (3DTSC), which is constructed by 1D carbon nanowires cross‐linked with 2D graphene nanosheets with high conductivity and polar 0D metal sulfide nanodots with efficient electrocatalytic activity and strong chemical adsorption capability for LiPSs, is presented. Benefiting from the well‐designed multiscale, multidimensional 3D porous nanoarchitecture with high conductivity, and efficient electrocatalytic and absorption ability, the 3DTSC significantly mitigates LiPS shuttle, improves the utilization of Li2S, and facilitates the transport of electrons and ions. As a result, even with a high Li2S loading of 8 mg cm−2, the freestanding 3DTSC‐Li2S cathode without a polymer binder and metallic current collector delivers outstanding electrochemical performance with a high areal capacity of 8.44 mA h cm−2.

Synthesis of magnetic, durable and superhydrophobic carbon sponges for oil/water separation

The clean-up of oil spills is a worldwide challenge for the prevention of serious environmental pollution. Therefore, it is imperative to develop materials for oil-spill cleanup that have high absorption/separation capacity, good selectivity, controlled collection and easy recyclability. Here, we present a facile and low-cost approach for fabricating magnetic, durable, and superhydrophobic carbon sponges. The resultant carbon sponges feature fast magnetic response, excellent superhydrophobicity/superoleophilicity, high chemical resistance, environmental stability and mechanical durability, as well as high oil/water separation efficiency and oil absorbency. More importantly, given the magnetically controllable property endowed by magnetic particles to superhydrophobic carbon sponges, which act as magnetically controlled “smart absorbents”, the carbon sponges can therefore controllably and selectively adsorb oils from oil-water mixtures. Thus, our strategy may open up a new avenue for developing magnetic responsive intelligent oil sorbent materials suitable for practical applications in the fields of water remediation, oil spill clean-up and oil recovery.

Asymmetric supercapacitor based on reduced graphene oxide/MnO2 and polypyrrole deposited on carbon foam derived from melamine sponge

Carbon sponges enclosing carbon fibers are prepared by carbonizing the melamine sponges with bunches of carbon fibers sewn in, and used as the substrate and current collector to fabricate asymmetric supercapacitors. MnO2/rGO/CS-CFs as the positive electrode and the PPy/CS-CFs as the negative electrode have been prepared and characterized, and in LiCl/polyvinyl alcohol gel electrolyte, the positive and negative electrodes are used to fabricate the asymmetric supercapacitors. The cells exhibit an operating voltage window of 1.4 V and high specific capacitance of 106.1 F g−1 based on the active materials and high cyclic stability (83.7% capacitance retention after 10000 cycles). The asymmetric supercapacitors in parallel and series connection show good electrical relationships, and two cells in series connection can turn on a light emission device after being charged, indicating the potential practical application.

Nitrogen-Doped Carbon as a Host for Tellurium for High-Rate Li-Te and Na-Te Batteries.

A nitrogen-doped hierarchical porous carbon sponge, used as a matrix for tellurium accommodation, was designed and prepared in this work. The porosity of the matrix played an important role in enhancing the electrochemical performance of Li/Na-Te batteries. Specifically, the mesopores could accommodate active materials whereas the macropores provided sufficient space for partial Te accommodation and volume expansion in discharge. In addition, N heteroatoms in carbon species could enhance the electrical conductivity and widen its application in lithium/sodium storage. The monolithic and flaky architecture of the nitrogen-doped hierarchical porous carbon sponge/tellurium composite offered a highly conductive network for fast electron transportation. As a result, the nitrogen-doped hierarchical porous carbon sponge/tellurium composite achieved a superior rate performance for Li-Te and Na-Te batteries.

Experimental and Performance Analyses on Elastomer-Strengthened Polyethylene Terephthalate/Glass Fiber Blends

Ethylene–methacrylate–glycidyl (EMG) copolymer is employed to strengthen polyethylene terephthalate (PET)/glass fiber (GF) blends. This paper starts from investigating the effects of various EMG contents on mechanical properties, thermal properties and fractured surface morphology of PET/GF blends. All of the above-mentioned properties own extreme limits of EMG concentration. The crystallization ability of the blends increases with an increment in EMG content, whereas the crystallinity keeps stable at a relatively high level of 0–20 wt.% EMG loading. The tension, bending and impact properties of PET blends are enhanced with the addition of a self-made three-dimensional hierarchical porous carbon sponge (3DC) based on an optimal additive amount. Results indicate that EMG possesses the capabilities of increasing the toughness of PET/GF blends remarkably and transforming the blends from brittle fracture to tough fracture. According to the results, the blends exhibit the best overall properties as the content of EMG reaches 10–15 wt.%.

Scalable, eco-friendly and ultrafast solar steam generators based on one-step melamine-derived carbon sponges toward water purification

Solar steam generation can be a practical and sustainable technology for wastewater purification and seawater desalination. However, both the inefficient utilization of solar energy and high complicity/cost of current solar steam generators hinder the scalable application of this technique. Herein, we demonstrate a facile, scalable and low-cost approach to produce highly-efficient solar steam generator via a one-step calcination of commercial melamine sponges (MS) in air. The in-air calcinated MS (AMS) with thermal insulator achieves an ultrafast solar evaporation rate (1.98 kg m−2 h−1) and a high photothermal efficiency (~92%) under one sun illumination (1 kW m−2), superior to most reported values. This high solar evaporation rate is attributed to the effective heat localization and adequate water supply in AMS, caused by the low bulk thermal conductivity, high porosity and hydrophilicity of AMS, as well as the set-up of a thermal insulator. The AMS is found to be highly efficient and stable, and it can be used to purify various types of waste water, including river water, seawater, and strong acid/alkaline water. Performance analysis of a large-scale prototype device based on the AMS design for field tests promises significant opportunities for highly-efficient, reusable, portable and low-cost water purification systems.

Three-dimensional carboxymethyl cellulose sponge-like ultralight electrode for lithium-ion batteries

In order to reduce the weight of the lithium-ion battery and increase its capacity, the copper foil as a conventional current collector is completely abandoned, and a novel ultralight negative electrode prepared by freeze-drying technology and carboxymethyl cellulose (CMC) has a 3D sponge-like structure. Further, graphite is employed as an electrode material. X-ray diffraction and Raman spectroscopy show no damage to the graphite structure during the formation of the carbon sponge. The thin layer of acetylene black deposit acts as a current collector and allows graphite to maximize contact with the electrolyte. In the half-cell experiment, this new 3D CMC spongy ultralight collector-free electrode achieves considerable cyclical stability. This paper describes innovative and fairly simple techniques to fully realize 3D CMC sponge-like current collector applied in lithium-ion battery, rather than relatively heavy and expensive copper foil, thereby improving the weight and volumetric energy density of such advanced batteries.

MnCo2O4+x nanowire arrays grown on carbon sponge: improved electrochemical and catalytic performances

MnCo2O4+x nanowire arrays with improved electrochemical and catalytic performances were successfully grown on carbon sponge via a hydrothermal–pyrolysis route.

Recent progress on electrochemical production of hydrogen peroxide

Hydrogen peroxide (H2O2), first synthesized in 1818 through the acidification of barium peroxide (BaO2) with nitric acid, is a clear and colorless liquid which is entirely miscible with water and variety of organic solvents such as carboxylic esters. Anthraquinone process (an old production process of H2O2), a batch process carried out in large facilities is an energy demanding process that requires large facilities, and involves oxidation of anthraquinone molecules and sequential hydrogenation. Moreover, the direct synthesis method enables production in a continuous mode as well as it permits small scale, decentralized production. Many drawbacks associated with these processes such as, energetic inefficiency and inherent disadvantages have motivated researchers, industry and academia to find out alternative for synthesis of H2O2. Electrochemical route based on catalyst selectively reduce oxygen to hydrogen peroxide. O2 is cathodically reduced to produce H2O2 via 2-electron pathway or 4-electron pathway to get H2O. Electrolysis of water has an important place in storage and electrochemical energy conversion process where problem is to choose a sufficiently stable and active electrode for anodic oxygen evolution reaction. Most commonly used catalysts on the cathode are carbon based materials such as carbon black, carbon nanotubes, graphite, carbon sponge, and carbon fiber. In perspective of expanding demand of production and usage of hydrogen peroxide we review the past literature to summarize different production processes of H2O2. In this review paper, we mainly focus on electrochemical production of hydrogen peroxide along with other alternatives such as, anthraquinone method for industrial H2O2 production and direct synthesis process. We also review the catalytic activity, selectivity and stability for enhanced yield of H2O2. From revision of experimental and theoretical data from the past literature; we argue that successful implementation of electrochemical H2O2 production can be realized on the basis of stable, active and selective catalyst.

Cotton-derived carbon sponge as support for form-stabilized composite phase change materials with enhanced thermal conductivity

The practical use of organic phase change materials (PCMs) for solar thermal energy storage is limited by the leakage problem and the low thermal conductivity. As a good supporting and thermal conductive framework for organic PCM with shape-stability, three-dimensional carbon sponges are produced by the direct carbonization of low-cost and sustainable biomass cotton. The carbon sponges are consisted of aerogels of the cotton-derived hollow carbon fibers, which have both interconnecting network and high porosity. The vacuum impregnated paraffin@carbon sponge composites not only present leakage-proof shape stability and enhanced thermal conductivity, but also show high thermal storage energy density (>200 J g-1, slightly lower than the pure paraffin) and good cyclability. The results indicate that the shape-stable PCMs as supported by cotton-derived carbon sponges are potentially to be widely used for thermal energy conversion and storage, especially for solar energy utilization.

Nickel nanoparticles activated highly porous carbon for excellent sodium storage

The development of sodium ion batteries (SIBs) is greatly restricted by the unsatisfactory anode materials with low capacity and poor cycling stability. Herein, we report a dual-activation hydrothermal process to prepare highly porous activated loofah sponge carbon (ALSC) and ALSC/Ni composite. ALSC is prepared by a facile KOH-based hydrothermal method and further embedded with Ni nanoparticles to form ALSC/Ni composite material by a simple NiCl2-treated hydrothermal pyrolysis. The as-obtained ALSC/Ni composite material has a 3D connected porous structure and a large specific surface area of 689.6 m2 g−1 due to the etching reaction between NiCl2 and carbon. Moreover, higher electrical conductivity and more active sites are achieved in the ALSC/Ni composite material. When applied as anode for sodium ion batteries, the ALSC/Ni electrode delivers a high reversible capacity of 325.4 mA h g−1 and keeps a capacity retention of 72.5% after 100 cycles at 20 mA g−1, much better than ALSC and other counterparts. Due to the unique porous structure and embedded nickel nanoparticles, the designed ALSC/Ni electrode also shows enhanced rate performance. Our work paves a new road for fabrication of high-performance carbon composite electrodes for SIBs.

Hydrogenated Na2Ti3O7 Epitaxially Grown on Flexible N-Doped Carbon Sponge for Potassium-Ion Batteries

With its inherent zig-zag layered structure and open framework, Na2Ti3O7 (NTO) is a promising anode material for potassium-ion batteries (KIBs). However, its poor electronic conductivity caused by large band gap (∼3.7 eV) usually leads to low-performance KIBs. In this work, we synthesize the fluff-like hydrogenated Na2Ti3O7 (HNTO) nanowires grown on N-doped carbon sponge (CS) as a binder-free and current-collector-free flexible anode for KIBs (denoted as HNTO/CS). High-resolution X-ray photoelectron spectroscopy (XPS) and electron spin-resonance spectroscopy (ESR) confirm the existence of Ti-OHs and O vacancies in HNTO. The first-principles calculation discloses that both Ti-OHs and O vacancies are equivalent to n-type doping because they can shift the Fermi level up to the conduction band, thus leading to a higher electronic conductivity and better performance for KIBs. In addition, the N-doped CS can further reinforce the conductivity and avoid the aggregation of HNTO nanowires during cycling. As a result, the as-made HNTO/CS can deliver a capacity of 107.8 mAh g-1 at 100 mA g-1 after 20 cycles, and keep the capacity of 90.9% and 82.5% after 200 and 1555 cycles, respectively, much better than the samples without hydrogenation treatment or N-doped CS and reported KTi xO y-based materials. Our work highlights the importance of hydrogenation treatment and N-doped CS in enhancing the electrochemical property for KIBs.

Nanoparticle@Metal-Organic Frameworks as a Template for Hierarchical Porous Carbon Sponges.

The preparation of hierarchical porous carbon sponges (HCS) from metal oxide nanoparticle@metal-organic frameworks is reported. ZnO nanoparticles are partially converted to zeolitic imidazolate framework-8 (ZIF-8) crystals in presence of n-butylamine to obtain ZnO@ZIF-8 porous hybrids. After direct carbonization, followed by ZnO acidic etching, ZnO@ZIF-8 crystals were converted to submicrometric HCS. Due to the high surface area and accessible porosity, combining micro- and mesoporosity of HCS, their application for the extraction of water pollutants was studied by preparing HCS/polymer membranes, and showed a high efficiency for the fast (650 L m-2 h-1 ) removal of plastic degradation by-products (DBP, dibutyl phthalate. DEHP, bis(2-n-ethylhexyl)phthalate). DBP and DEHP breakthroughs were lower than 3 % after the filtration of 100 mL of water containing simultaneously both phthalates at a high concentration level (300 μg L-1 , each). HCS/polymer membranes were reusable up to 5 times, maintaining their extraction capacity, with relative errors of 6 % for DBP, and <1 % for DEHP.

A novel rechargeable hybrid Na-seawater flow battery using bifunctional electrocatalytic carbon sponge as cathode current collector

A novel rechargeable hybrid Na-seawater flow battery, using natural seawater as an abundant source of active materials, have been developed recently. In this kind of metal-air battery, electrochemical oxygen evolution and reduction are the two key processes taking place during charging and discharging, respectively. In general, powder form of electrocatalysts are attached to the current collectors by using inactive and insulating polymer binders, which inevitably impede the overall performance, and increase the manufacturing costs of the battery. Therefore, a simple way to construct the 3D current collector combined with efficient electrocatalytic activities remains a big challenge. In this work, a 3D macroporous carbon sponge is prepared by the direct carbonization of commercially available polymer “Magic Eraser”. The obtained carbon sponge has interconnected macroporous open 3D scaffold structure and exhibits good flexibility and tailorability. The 3D macroporous carbon sponge shows good bifunctional electrocatalytic activities toward oxygen evolution and reduction reactions in seawater. The fabricated hybrid Na-seawater flow battery using 3D macroporous carbon sponge as cathode current collector displays small charge-discharge voltage gap with high voltage efficiency, excellent rechargeability, and long-term cycling stability.

Fabrication of Mo2C coating on molybdenum by contact solid carburization

Recently a contact solid carburization method to fabricate carbide coatings on refractory metals was proposed. The principle is to hot-press the refractory metal with a “carbon sponge” (e.g. cast iron or high-carbon steel) which contains interstitial carbon atoms. When they contact in atomic scale at high temperatures, the carbon atoms diffuse into the refractory metal matrix and then dense carbide coatings on the substrates can be obtained since most refractory metals are carbide forming elements. In this article, we apply this method to prepare carbide coating on molybdenum (Mo). Cast iron is used as the “carbon sponge” and hot-pressed with textured Mo at constant temperature and pressure (18 MPa). We set the temperature at 1100 °C and 900 °C separately, we found that coatings containing Fe-Mo-C layer and Mo-C layer are generated at 1100 °C while coatings containing only Mo-C layer are formed at 900 °C. We then hot-pressed the samples at 900 °C for 2–10 h and systematically investigated the microstructure and some basic properties of the coatings obtained at 900 °C. The coating grows inward, it is pure ceramic and completely dense. The coating is composed of columnar Mo2C grains whose grain orientations are randomly distributed. The metal and carbide phases are metallurgically bonded with incoherent interfaces. The coating thickness reaches 1.8 μm when annealed for 10 h. As expected, the surface hardness is remarkably improved and the coating adhesion is strong. This technique is also expected to be used to improve the wear resistance, oxidation resistance for molybdenum and Mo based alloys and may also provide a new strategy to prepare Mo2C superconductors and catalysts.