Porous Carbon Tubes Research Articles

Constructing yolk@multi-shell free-standing anodes with porous carbon tube and SnS2 nanosheets for Si-based lithium-ion batteries

Constructing yolk@multi-shell free-standing anodes with porous carbon tube and SnS2 nanosheets for Si-based lithium-ion batteries

Cotton induced graphene-like carbon tubes as electrodes for ultrahigh-energy–density supercapacitors

Developing a simple, cost-effective method to synthesize carbon tubes with unique physicochemical properties is of great value for energy storage/conversion applications. In this study, cotton-induced O, N-doped graphene-like hierarchically structured porous carbon tubes (CTOs) were fabricated through a facile method and used as a supercapacitor electrode. The CTOs possessed enhanced porosity, a unique pore structure, and a large specific surface area (3,345.4 m2 g−1), and the electrode demonstrated an ultrahigh specific capacitance of 428.2 F g−1 at 1.0 A g−1 and remarkable cycle stability (93.3 % after 10,000 cycles). Density functional theory calculations confirmed that the high-level O, N-doped graphene-like hierarchically porous structures increased ion transfer efficiency and conductivity. When NiCo2S4/CTOs and CTOs were used as the positive and negative electrodes, respectively, the asymmetric supercapacitors (NiCo2S4/CTOs//CTOs) exhibited an extremely high specific capacitance of 180.8 F g−1 and a maximum energy density of 64.3 Wh kg−1. Moreover, two serially connected NiCo2S4/CTOs//CTOs capacitors could power a 9 W alarm clock for 26 min. The proposed approach enables the facile synthesis of superior carbon tubes using long-staple cotton, offering potential energy storage and conversion.

Experimental investigation of a desalination system using porous carbon tube as a humidification media with swirl flow

Humidification-dehumidification (HDH) technology is a technique for small-scale water desalination applications based on carrier gas humidification motivated by thermal energy. The present work introduces an experimental investigation of a desalination unit based on HDH method. The main objective of this study is to evaluate the heat and mass transport properties of porous carbon tubes (PCT) as a humidification medium with swirl flow for HDH unit. Processes for transferring heat and mass are investigated at varied the temperatures of water and air, water-to-air mass ratios (MR), and helical flow channel pitch (HCP). The performance analysis is investigated based on some of performance metrics such as gained output ratio (GOR), humidification efficiency (ηH), exergy efficiency (ηex), sustainability indicator (SI), and water cost (WC). Results indicate that the increase in MR and HCP increases all of performance parameters. High values of MR based on low air flow rate decrease the entropy generation and enhance the exergy efficiency. The humidity efficiency and GOR improve with the rise in the MR based on the water flow rate. The study of sustainability indicator shows that the proposed system has possibilities of doing business. It still has room for energy improvement and losses, though. The system's usability will increase after these modifications are made. When the process temperature associated with heating the feed water or/and input air rises, more freshwater is produced. The proposed system's maximum hourly yield reaches about 0.225 L with cost 0.078 cent. The best value of GOR, exergy efficiency, humidification efficiency and suitability indicator performed by the current system are about 3, 51.67 %, 48.72 % and 2.07 respectively.

Biomass-Derived Bifunctional Cathode Electrocatalyst and Multiadaptive Gel Electrolyte for High-Performance Flexible Zn-Air Batteries in Wide Temperature Range.

High-efficiency and low-cost bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), as well as gel electrolytes with high thermal and mechanical adaptability are required for the development of flexible batteries. Herein, abundant Setaria Viridis (SV) biomass is selected as the precursor to prepare porous N-doped carbon tubes with high specific surface area and the 900°C calcination product of SV (SV-900) shows the optimum ORR/OER activities with a small EOER -EORR of 0.734 V. Meanwhile, a new multifunctional gel electrolyte named C20E2G5 is prepared using cellulose extracted from another widely distributed biomass named flax as the skeleton, epichlorohydrin as the cross-linker and glycerol as the antifreezing agent. C20E2G5 possesses high ionic conductivity from -40 to + 60 °C, excellent tensile and compressive resistance, high adhesion, strong freezing and heat resistance. Moreover, the symmetrical cell assembled with C20E2G5 can significantly inhibit Zn dendrite growth. Finally, flexible solid-state Zn-air batteries assembled with SV-900 and C20E2G5 show high open circuit voltage, large energy density, and long-term operation stability between -40 and + 60°C. This biomass-based approach is generic and can be used for the development of diverse next-generation electrochemical energy conversion and storage devices.

Porous carbon tubes from recycling waste COVID-19 masks for optimization of 8 mol% Y2O3-doped tetragonal zirconia polycrystalline nanopowder

Disposable polypropylene medical masks are widely used to protect people from injury caused by COVID-19 worldwide. However, disposable medical masks are non-biodegradable materials, and the accumulation of waste masks can pollute the environment and waste resources without a reasonable recycling method. The aims of this study are to transform waste masks into carbon materials and to use them as a dispersant in preparing high-quality 8 mol% Y2O3-doped tetragonal zirconia nanopowders. The waste masks were carbonized to get a carbon source in the first step, then KOH was used to etch the carbon source creating a micropores structure in the carbon material after the carbon-bed heat treatment method. The resulting carbon material is a porous tube structure with a high specific surface area (1220.34 m2/g) and adsorption capacity. The as-obtained porous carbon tubes were applied as a dispersant to produce 8 mol% Y2O3-doped tetragonal zirconia nanopowders, and the resulting nanopowders owned well-dispersed and had the smallest particle size than that prepared by activated carbon as a dispersant. Besides, the sintered 8 mol% Y2O3-doped tetragonal zirconia ceramic possessed high density, which resulted in higher ionic conductivity. These findings suggest that waste face masks can be recycled to prepare high-added-value carbon materials and provide a green and low-cost method to reuse polypropylene waste materials.

Hollow 1D carbon tube core anchored in Co3O4@SnS2 multiple shells for constructing binder-free electrodes of flexible supercapacitors

The design of the core@multi-shell metal sulfide hollow tube is of great importance for various supercapacitor electrodes. Herein, a hollow carbon tube (HCT) core@multi-shell with rich pores is developed for constructing the binder-free flexible electrodes (HCT-x@Co3O4@SnS2). The inner core–shell is derived from the zeolitic imidazole framework (ZIF)-8@ZIF-67 porous carbon tube and is engineered with vertically aligned SnS2 nanosheets. The unique inner core–shell and the outer-shell SnS2 contribute to the excellent characteristics, including abundant pores and channels for the rapid ion transport and storage, high specific surface area, improved electrical conductivity, and additional electroactive sites for the faradaic reaction. Thanks to the synergies between the unique 1D porous hollow structure and the different components, the as-fabricated HCT-2@Co3O4@SnS2 electrode exhibits a high specific capacitance of 439 F/g at 1 A/g. Moreover, the assembled flexible supercapacitor also demonstrates a remarkable energy density of 40.22 Wh kg−1, the corresponding power densities of 750.22 W kg−1, and long cycle life. In addition, no structural deformation and capacitance loss are observed in the bended devices. The developed approach provides a facile structure design route for the flexible binder-free electrode preparation of flexible energy storage applications.

Hybrid hierarchically porous carbon micron tubes for trace cadmium and lead ions electrochemical detection

The nitrogen, sulfur codoped hierarchical porous carbon tubes were synthesized using oxidized asphaltene, melamine and trithiocyanuric acid, it showed excellent performance in the detection of trace amounts of Cd2+/Pb2+ thanks to its rich sulfur and nitrogen functional groups as well as hierarchical porous tube structure. The introduction of oxidized asphaltene increased the conductivity of the resultant carbon material while retaining a high sulfur content (6.13 wt%). Under the optimum conditions, the resultant porous carbon tube was used as electrochemical detection sensor for heavy metal ions. The sensitivities and detection limits for individual Cd2+ and Pb2+ were 19.4802 and 33.2850 μA/μM, 2.80 and 1.38 nM; while the sensitivities and detection limits for simultaneous Cd2+ and Pb2+ were 14.5474 and 37.3337 μA/μM, 3.75 and 1.23 nM, respectively. This sensor also was utilized to detect actual water samples, and it was successful in measuring environmental heavy metal contaminants with acceptable recoveries of 97.34–102.83% for Cd2+ and 97.46–106.47% for Pb2+.

Construction of polysulfides defense system for greatly improving the long cycle life of metal sulfide anodes for sodium-ion batteries

Metal sulfides are promising anode materials for sodium ion batteries (SIBs) due to their high theoretical specific capacity and abundant source. Nevertheless, significant challenges, including large volume change, sluggish Na+ transport kinetics and polysulfides intermediates, have greatly affect their long cycle stability. Unfortunately, the majority of current studies only focus on the first two aspects, but lack of sufficient attention and insights into the effect of polysulfides intermediates. Here, a porous of CoSx (P-CoSx) electrode material is fabricated as an example to investigate the influence of polysulfides on its cycling performance. The results show that polysulfides cause a slight loss of reversible capacity during the battery cycling, while the failure of the battery is due to its significant fluctuations in reversible capacity after extensive cycles. Detailed analyses demonstrate that the intense fluctuation in capacity originates from the faster growth of dendrites caused by the reaction of sodium polysulfides with sodium foil and/or the reaction of elemental sulfur with sodium foil to penetrate the separator, resulting in a local short circuit. To suppress these undesirable side reaction, N, S co-doped porous carbon tubes (N, S-PC) rich in C–S and C–N bonds have been added to adsorb polysulfides and alleviate their reaction with sodium foil. As a result, the capacity of the P-CoSx electrode with N, S-PC (P-CoSx/N, S-PC) remains stable without significant fluctuations for 1000 cycles, which is much better than that of the pure P-CoSx electrode (intense fluctuation in capacity after 320 cycles). Our work offers insights into the crucial influence of polysulfides on the cycle performance of the P-CoSx anode and provides a feasible strategy to prolong the cycle life of metal sulfide anode for SIBs.

Study of heat and mass transfer through a porous carbon tube as a humidification media for evaporative cooling system with swirl flow

This study presents an experimental investigation to assess the heat and mass transfer process characteristics of porous carbon tubes as a humidification medium with swirl flow. The aim is building an eco-friendly self-cooling system that relies on the evaporation process of absorbed water. Heat and mass transfer processes are tested at various air and water temperatures and flow rates, in addition to the pitch of the helical flow channel. Results indicate that the maximum depression of the dry bulb temperature reached about 19.40 °C. Experimental results show that the cooling efficiency of the proposed system could reach values as high as 94.6%. The cooling performance is strongly dependent on the helical flow channel pitch and the air flow rate. Also, the proposed system can perform COP equal to 2.85 as a maximum value. Using the helical channel to make a more compact evaporative cooling system is an effective suggestion. At long last, empirical correlations for estimating the system performance parameters as far as different operating parameters and system size are performed. The novel porous activated carbon studied in this paper provides a solution for solving the poor wettability problem in evaporative cooling systems. Besides, it improves thermal performance.

Porous Carbon Tubes Constructing Freestanding Flexible Electrodes for Symmetric Potassium-Ion Hybrid Capacitors

Developing electrode materials to apply in anodes and cathodes with superior kinetics and high specific capacity still remains a serious challenge for potassium-ion hybrid capacitors (PIHCs). Herein, a well-designed flexible freestanding electrode consisting of porous carbon tubes (FSF-PCTs) that functioned as both an anode and a cathode for PIHCs presents favorable energy storage performance. Based on this fully carbon-based FSF-PCTs electrode, symmetrical freestanding potassium-ion hybrid capacitors (SPIHCs) are developed. Moreover, SPIHCs deliver good practical application in terms of a high power density of 8109.9 W kg–1 (at 39.2 W h kg–1), a high energy density of 117.8 W h kg–1 (at 450 W kg–1), and a great cycle stability of 51 W h kg–1 at 1 A g–1 after 1500 cycles as well as ultrafast charge and slow discharge characteristics (full charge in only 1 min and the discharge time lasting for 15 min). Moreover, systematic characterization analysis in half potassium-ion batteries (PIBs) reveals that the K+ storage mechanism in anode FSF-PCTs is a synergistic effect of intercalation and surface capacitance, and the operating principle of FSF-PCTs as a cathode is an adsorption behavior of PF6– on its surface.

Controllable synthesis of porous tubular carbon by a Ag+-ligand-assisted Stöber-silica/carbon assembly process.

Herein, in this study, we utilized Ag+-ligand interactions for critically regulating the morphology of carbon by the Stöber-silica/carbon co-assembly method for the first time. Tetraethyl orthosilicate (TEOS) and resorcinol/formaldehyde (RF) assemble upon dictation by Ag+ and pyridyl-functionalized surfactants, producing porous carbon tubes (RF1) with a high surface area of 696 m2 g-1 and accessible mesopores ∼15 nm in size. Furthermore, when using tetrapropyl orthosilicate (TPOS) with a slower hydrolysis rate than that of TEOS, carbon tubes (RF2) with enhanced uniformity and a surface area as high as 2112 m2 g-1 are generated. Additionally, when using dopamine hydrochloride instead of RF as a carbon precursor, tubular polydopamine (TDA) with lengths of tens of microns is fabricated, which exhibits excellent catalytic activity toward oxygen reduction reactions in alkaline solutions due to its unique structural feature, a high surface area of 1350 m2 g-1, metallic silver remains of 8.3 wt%, and a rich nitrogen content of 3.6 wt%. This work sheds light on the engineering of a micellar soft template and synthesizing novel nanostructures by the extension of the Stöber method.

Ultra-High Energy Stored into Multi-Layered Functional Porous Carbon Tubes Enabled by High-Rate Intercalated Pseudocapacitance

Ultra-High Energy Stored into Multi-Layered Functional Porous Carbon Tubes Enabled by High-Rate Intercalated Pseudocapacitance

Growing NiS2 nanosheets on porous carbon microtubes for hybrid sodium-ion capacitors

NiS2 is a promising anode material for sodium-ion batteries (SIBs) and capacitors (SICs). However, the sluggish Na+ diffusion and large volume change of bulk NiS2 during sodiation/de-sodiation lead to poor rate capability and fast capacity decay, limiting its practical application. Herein, we design and prepare well-oriented NiS2 nanosheets on porous carbon microtubes (denoted as NiS2/pCMT) as a novel anode material for SIBs/SHCs. The unique porous hollow carbon tubes and NiS2 nanosheets can well relieve the repeated stress/strain and maintain the structural integrity of the composite anode during long-term charging/discharging. As a confirmation, a modelled SHC is constructed by using the NiS2/pCMT composite as anode and coupling with an activated carbon cathode, delivering a high energy density of 136 Wh kg−1 and good cycling stability. The first-principles density functional theory (DFT) calculations confirm that the NiS2 nanosheets surface has a high chemical affinity towards Na+ ions, promising the concentration of Na+ ion on/nearby the surface for fast redox reactions during sodiation/de-sodiation of NiS2. This work provides some new insights for the design and fabrication novel composite electrode materials for applications in beyond lithium-ion batteries/capacitors.

Nitrogen-doped porous carbon tubes composites derived from metal-organic framework for highly efficient capacitive deionization

Electrode materials with high electrosorption capacity and stable cycling performance are desired by the capacitive deionization (CDI) process. A novel CDI electrode is prepared by developing the nitrogen-doped porous carbon tubes composite (PCT-N) material. It consists of interconnected tubular network construction and hierarchical porous structure. The electrospun polyacrylonitrile/zinc acetate (PAN/Zn(Ac)2) nanofibers coated with a layer of zeolitic imidazolate framework (ZIF, a subfamily of metal-organic frameworks) nanocrystals are used as precursors for carbonization. The prepared PCT-N material has high nitrogen-doping amount and hollow macroporous structure with lateral mesopores. It has advantages of excellent electrical conductivity, higher specific surface area and larger total pore volume. The material exhibits a salt adsorption capacity of 16.7 mg g−1 in 500 mg L−1 initial NaCl solution, and shows good cycle stability over 100 cycles. Such a PCT-N electrode provides a promising alternative candidate for developing CDI technology.

Bio template route for fabrication of a hybrid material composed of hierarchical boehmite, layered double hydroxides (Mg-Al) and porous carbon on a steel fiber for solid phase microextraction of agrochemicals.

Nanosheets of a porous layered double hydroxide were directionally arranged on boehmite nanowires and porous carbon and used as a coating for solid-phase microextraction (SPME) method. Porous carbon tubes were prepared from goat grass and then coated with layered double hydroxide nanosheets and boehmite nanowires. The nanomaterial was placed on a stainless-steel wire which then was used for the extraction of fifteen agrochemicals from aqueous sample solutions. The extraction temperature, extraction time, ionic strength, stirring rate, and desorption temperature and time were optimized. Following thermal desorption of the agrochemicals in the injector of the gas chromatograph, they were quantified by GC/MS. Under optimum conditions, the repeatability for one fiber, expressed as relative standard deviation, was between 2.9 and 11.1%. The detection limits for the agrochemicals are between 2-29 ngL-1. The method is simple, fast, and inexpensive (in terms of equipment). The fiber is thermally stable, and the relative recoveries from spiked samples are better compared to conventional methods of extraction. Graphical abstract Schematic illustration of the preparation of three-dimensional hierarchical boehmite/ layered double hydroxides/ porous carbon (Boeh/LDH/pC) SPME fibers and application for the extraction of fifteen agrochemicals from aqueous sample solutions following quantification by GC/MS.

Porous hollow carbon tube derived from kapok fibres as efficient metal-free oxygen reduction catalysts

Pyrogenic biomass carbon has been deemed a promising alternative to Pt/C for the oxygen reduction reaction (ORR) owing to its low cost, excellent activity, and eco-friendly properties. Herein, a porous carbon tube material derived from kapok fibres was prepared by combining activation with pyrolysis. Electrochemical measurements demonstrated that the kapok fibre-derived material prepared at 900°C had excellent ORR performance with a half-wave potential –0.14 V (vs. Ag/AgCl) close to that of commercial Pt/C (–0.13 V vs. Ag/AgCl) in 0.1 mol L–1 KOH. The prepared material also displayed remarkable methanol tolerance and durability. Furthermore, the maximum power density output of the microbial fuel cell using the prepared material was (801± 40) mW m–2, comparable to that of the Pt/C cathode ((778± 31) mW m–2). The present work provides a facile way of using economical and renewable biomass to develop a porous structure and high-activity cathode ORR catalyst for fuel cell applications.

Biomass-derived hierarchical honeycomb-like porous carbon tube catalyst for the metal-free oxygen reduction reaction

Biomass carbon materials have been deemed a promising metal-free catalyst for the oxygen reduction reaction (ORR) owing to their renewable, high electrical conductivity and large surface area. However, the required ion transfer process is hampered by an inappropriate porous structure. In this work, a nitrogen-doped honeycomb-like carbon tube with porous structure was synthesized by the pyrolysis of dandelion seed. The results showed that the material prepared at 900°C (HHPT-900) possessed abundant pores of different sizes, which could provide more active sites and ion channels than other biomass carbon materials investigated so far. In addition, the onset potential of HHPT-900 was 0.83V vs. reversible hydrogen electrode (RHE), close to that of commercial Pt/C (0.85V vs. RHE) in 0.1molL−1 KOH. HHPT-900 also proved to be highly methanol tolerant and durable. Furthermore, a higher power density (975±46mWm−2) was obtained when using HHPT-900 as a cathode catalyst in a microbial fuel cell than that of the Pt/C cathode (823±41mWm−2). The present work provides an easy way to develop a hierarchical honeycomb-like porous carbon tube material that could be used as an effective metal-free ORR catalyst.

Spatially confining and chemically bonding amorphous red phosphorus in the nitrogen doped porous carbon tubes leading to superior sodium storage performance

A rationally designed P/C anode with red P encapsulation into nitrogen doped porous carbon tubes demonstrates excellent sodium storage performance.

Cable-like double-carbon layers for fast ion and electron transport: An example of CNT@NCT@MnO2 3D nanostructure for high-performance supercapacitors

A unique nanostructure consisting of CNTs as carbon matrix, and were sequentially coated with silicon dioxide, N-doped porous carbon tube (NCT) and MnO2 nanoflowers, the final CNT@NCT@MnO2 composites with large internal voids between CNT and NCT. CNT@NCT@MnO2 combines the nanostructural advantages of internal voids and the N-doped porous carbon, presenting fast diffusion paths for ions and electrons, high conductivity and large surface areas. When used as an anode material in supercapacitors, the CNT@NCT@MnO2 tube-in-tube hierarchical nanostructure exhibite a remarkably excellent electrochemical behavior with a specific capacitance (Csp) of 210 F g−1 at the current density of 0.5 A g−1. Moreover, all-solid-state asymmetrical supercapacitors (ASCs) were fabricated using the CNT@NCT@MnO2 composites as anode and the CNT@NCT as cathode, Na2SO4/PVA gel as the electrolyte and the separator. The all-solid-state ASCs also show the superior performance, such as high energy density of ∼14 Wh kg−1 and a power density of ∼3.6 kW kg−1.

Enhanced Photocatalytic H2 Production on Three-Dimensional Porous CeO2/Carbon Nanostructure

A versatile biotemplate method is developed for the fabrication of porous carbon tubes embedded with CeO2 quantum dots (QDs) as a high-efficiency photocatalyst by using bean sprouts. Interestingly, this novelly hierarchical three-dimensional porous CeO2 QDs/carbon exhibits an enhanced hydrogen evolution feature from water splitting under xenon lamp irradiation. The excellent performance of the said material is attributed to the synergistic effect between CeO2 QDs and carbon films, inlaid ceria QDs structure, biomorphic porous architecture, a high specific surface area, and abundant oxygen vacancies. This encouraging result reveals a reproducible approach for processing metal oxide QDs/carbon photocatalysts with high reactivity and shows the possibility for energy application.