Multiporous Carbon Research Articles

High performance bagasse based iron–nitrogen-carbon catalyst for oxygen reduction reaction

The design and synthesis of highly stable and low-cost for the oxygen reduction reactions (ORR) catalysts to replace non-noble metal catalysts is crucial for their applications in fuel cells. In this work, bagasse activated carbon (BAC) was used as the carbon source to prepare the high specific area and multi-porous carbon. The BAC@FeN catalysts derived from BAC, FeCl2 and melamine were prepared by pre-activation treatment and high-temperature pyrolysis. The BAC@FeN-900–30 catalyst encapsulated with Fe3C and Fe3O4 exhibited an outstanding catalytic activity (Eonset = 1.01 V and E1/2 = 0.87 V) and superior operational stability of 90.50 % compared to Pt/C (20 wt%) catalyst. The results demonstrated that iron, carbon and nitrogen piggybacked BAC could generate abundant Fe-Nx active sites, which greatly improved the catalytic activity of ORR and had a broad application prospect in energy conversion.

Kraft lignin-derived multi-porous carbon toward sustainable electro-Fenton treatment of emerging contaminants

Reclaiming biomass waste to carbon cathode is promising to construct a sustainable electrochemical system. Here, we developed a novel thermal foaming process to reform kraft lignin to a free-standing and multi-porous carbon foam, which can be used as carbon cathode for electro-Fenton treatment of emerging contaminants (ECs). Benefiting from the excellent physicochemical and electrochemical properties with multi-porous and graphitic structure, the synthesized carbon foam cathode enhanced the electrocatalytic generation of H2O2 and •OH, and subsequently promoted the mass transfer and interactions among reactants (i.e., O2, H2O2, Fe2+, •OH, natural organic matters, and ECs). Eventually, an efficient degradation of ECs was achieved most likely via the multi-step •OH addition, cleavage, and ring opening reactions. Overall, the outcomes of this work provide a sustainable and applicable design and strategy to upgrade lignin-containing biomass to carbon cathode for efficient ECs remediation.

Differentiating ion transport of water-in-salt electrolytes within micro- and meso-pores of a multiporous carbon electrode

The transport of ions within a porous carbon electrode is governed by ionic association when using concentrated aqueous electrolytes, impacting the power and energy of electrochemical energy storage devices.

Fabrication of Activated Multiporous Carbon Nanofibers Using Vacuum Plasma for High-Capacity Energy Storage

Porous carbon nanofibers are widely used as supercapacitor electrode materials due to their excellent physical adsorption/desorption operation and smooth transport of ions. The acid/base activation method is commonly used to generate micropores on the surface of carbon nanofibers, but controlling the activation level and minimizing the release of harmful chemicals pose challenges. This study proposed a method for producing activated multiporous carbon nanofibers that is easier to operate and more environmentally friendly. It utilizes the vacuum plasma process to enhance surface area and introduce functional groups onto the electrospun polymer nanofibers. Subsequent heat treatment results in the formation of activated multiporous carbon nanofibers. The type and density of the functional group introduced into the carbon structure were adjusted to the type of plasma gas (O2, NH3 and C4F8) being exposed. Among them, oxygen plasma-treated carbon nanofibers (O-MPCNFs) not only have a much larger active surface (517.84 m2 g−1) than other gases (290.62 m2 g−1 for NH3 and 159.29 m2 g−1 for C4F8), but also generate a lot of micropores, promoting rapid adsorption/desorption-inducted charges; therefore, they have excellent energy storage capacity. The O-MPCNF-based symmetrical two-electrode supercapacitor has a high specific capacitance (173.28 F g−1), rate capability and cycle stability (94.57% after 5000 cycles).

Waste bamboo‐derived biochar and multiporous carbon as adsorbents for methyl orange removal

AbstractMaterialsMultiporous carbon (MPC) with a high specific surface area (1121 m2g−1) and mesoporous and microporous structures was prepared by using bamboo biochar (308 m2g−1) as raw material.MethodsThe preparation involved a CaCO3 activation process, where CaCO3 served as both the template for mesopores and the activating agent for micropores. The template could be easily removed by dilute HCl(aq) solution, making the preparation process simpler and more environmentally friendly compared to using mesoporous SiO2 as a hard template.ResultsThe performance of the MPC and biochar as adsorbents for methyl orange (MO) dye was investigated by means of thermal dynamic isotherms and kinetic models tests. The Langmuir isothermal analysis results revealed that the MPC exhibited a significantly higher MO adsorption capacity (344.8 mg g−1) compared to the bamboo biochar (12.4 mg g−1). The adsorption kinetics of the MPC followed a pseudo‐second‐order model.ConclusionOverall, the obtained MPC material offers a cost‐effective, environmentally friendly, and efficient solution for removing dyes from aqueous solutions.

Preparation of Advanced Multi-Porous Carbon Nanofibers for High-Performance Capacitive Electrodes in Supercapacitors.

The booming demand for energy storage has driven the rapid development of energy storage devices such as supercapacitors, and the research on high-performance electrode materials, a key component of supercapacitors, has gained tremendous attention. In this research, phenolic resin-based multi-porous carbon nanofibers have been prepared by electrospinning, curing, carbonization and activation and then employed as advanced electrode materials in supercapacitors. We demonstrate that the material is nano-scale continuous fiber, and its surface has pore distribution of different sizes. It delivers a high specific capacitance of 242 F g-1 at a current density of 0.2 A g-1 and maintains 148 F g-1 even at a high current density of 20 A g-1. Moreover, it shows almost no capacitance decay at a current density of 2 A g-1 over 1000 cycles, demonstrating its great potential as high-performance electrodes in supercapacitors.

Synergistically boosted non-radical catalytic oxidation by encapsulating Fe3O4 nanocluster into hollow multi-porous carbon octahedra with emphasise on interfacial engineering

Investigating the mechanisms of interfacial processes of supported metal catalysts is crucial for advanced oxidation processes (AOPs) of peroxymonosulfate (PMS) activation on efficient water remediation. In this research, we have successfully synthesized an exclusive nanocarbon catalyst encapsulating Fe3O4 nanoparticles in hollow multi-porous structures (termed ‘H-Fe3O4@C') as a catalyst for activating PMS towards the degradation of bisphenol-A (BPA). Superior catalytic performance of H-Fe3O4@C was observed as BPA was completely degraded within 40 min. This observation ascribed to stronger interfacial interactions between the Fe and C layer, which could be attributed to the presence of multiple Fe-C bonding that allows for electron tunnelling to the adjacent carbons than Fe3O4. The results of density functional theory calculations show that the Fe3O4 active center encapsulated in the center of the carbon framework can regulate the adsorption tenderness of carbon materials, resulting in excellent interfacial interaction provided optimal active sites with low adsorption energy(−1.31 eV) and long O-O bond(dO-O = 1.592 Å). Electrochemical analysis conceded that the atomic interfacial bonds (Fe-C) promoted electronic communication between surfaces. At the same time, the vacuum packaging structure enhances the stability of the catalyst and prevents the continuous leaching of active metals. The dissolved iron concentration after the reaction of H-Fe3O4@C was only 3.37% of that of bare Fe3O4 (14.6 mg L−1). Overall, this research sheds a new insights on the critical role of strong interfacial interactions in non-radical activation of PMS.

Efficient Photothermal Elimination of Formaldehyde under Visible Light at Room Temperature by a MnOx-Modified Multi-Porous Carbon Sphere.

Volatile organic compounds (VOCs) exert a serious impact on the environment and human health. The development of new technologies for the elimination of VOCs, especially those from non-industrial emission sources, such as indoor air pollution and other low-concentration VOCs exhaust gases, is essential for improving environmental quality and human health. In this study, a monolithic photothermocatalyst was prepared by stabilizing manganese oxide on multi-porous carbon spheres to facilitate the elimination of formaldehyde (HCHO). This catalyst exhibited excellent photothermal synergistic performance. Therefore, by harvesting only visible light, the catalyst could spontaneously heat up its surface to achieve a thermal catalytic oxidation state suitable for eliminating HCHO. We found that the surface temperature of the catalyst could reach to up 93.8 °C under visible light, achieving an 87.5% HCHO removal efficiency when the initial concentration of HCHO was 160 ppm. The microporous structure on the surface of the carbon spheres not only increased the specific surface area and loading capacity of manganese oxide but also increased their photothermal efficiency, allowing them to reach a temperature high enough for MnOx to overcome the activation energy required for HCHO oxidation. The relevant catalyst characteristics were analyzed using XRD, measurement of BET surface area, scanning electron microscopy, HR-TEM, XPS, and DRS. Results obtained from a cyclic performance test indicated high stability and potential application of the MnOx-modified multi-porous carbon sphere.

Fabricating multi-porous carbon anode with remarkable initial coulombic efficiency and enhanced rate capability for sodium-ion batteries

Due to the abundant sodium reserves and high safety, sodium ion batteries (SIBs) are foreseen a promising future. While, hard carbon materials are very suitable for the anode of SIBs owing to their structure and cost advantages. However, the unsatisfactory initial coulombic efficiency (ICE) is one of the crucial blemishes of hard carbon materials and the slow sodium storage kinetics also hinders their wide application. Herein, with spherical nano SiO2 as pore-forming agent, gelatin and polytetrafluoroethylene as carbon sources, a multi-porous carbon (MPC) material can be easily obtained via a co-pyrolysis method, by which carbonization and template removal can be achieved synchronously without the assistance of strong acids or strong bases. As a result, the MPC anode exhibited remarkable ICE of 83% and a high rate capability (208 mAh/g at 5 A/g) when used in sodium-ion half cells. Additionally, coupling with Na3V2(PO4)3 as the cathode to assemble full cells, the as-fabricated MPC//NVP full cell delivered a good rate capability (146 mAh/g at 5 A/g) as well, implying a good application prospect the MPC anode has

Sodium-chloride-assisted synthesis of nitrogen-doped porous carbon shells via one-step combustion waves for supercapacitor electrodes

• Sodium-chloride-assisted porous carbon synthesis is developed by combustion waves. • Thermochemical reactions pass through core–shell hybrids of NaCl-nitrocellulose. • Nitrogen-doped cube-like hierarchical porous carbon shells are obtained in seconds. • Multi-scale pores and high N-doping ratio improve active site area and conductivity. • Supercapacitors using the electrodes exhibit outstanding capacitance and stability. Heteroatom-doped, multiporous carbon structures are of considerable interest as high-performance electrochemical electrodes. However, their complex and time-consuming synthetic procedures impede a scalable production. Herein, a combustion-driven sodium-chloride-assisted synthesis route of nitrogen-doped, cube-like hierarchical porous carbon shells (N-C-HPCS) is developed for the electrode materials of supercapacitors. Free-standing hybrid films composed of nitrocellulose and NaCl particles serving as the chemical fuel layer and templates are prepared, and self-propagating combustion waves passing through the films within a few seconds fabricate controllable nitrogen-doped porous carbon (N-PC) after the simple removal of the templates by washing. The optimal tuning of thermochemical reactions through the nitrocellulose loadings leads to synthesizing the N-C-HPCS, while other precursors produce sparse or dense N-PC structures. Supercapacitor electrodes using the developed N-C-HPCS exhibit an outstanding specific capacitance (305F/g at 0.5 A/g) and retention at a high current density (∼78 % at 16 A/g), as well as long-term cyclic stability (∼116% after 10,000 cycles). The symmetric two-electrode cell exhibited high power and energy densities (8 kW/kg and 10.1 Wh/kg) and superb cycling stability (107.7 % after 10,000 cycles at 5 A/g). This work will inspire rational synthesis strategies for versatile N-PCs, useful for supercapacitors, batteries, catalysts, filters, and CO 2 adsorption.

Synthesis of Multiporous Carbons from the Water Caltrop Shell for High-Performance Supercapacitors.

In this study, an economic, sustainable, and green synthesis method of multiporous carbons from agricultural waste, water caltrop shell (denoted as WCS), was presented. To prepare the WCS biochar, the dried WCS was first carbonized to a microporous carbon with a surface area of around 230 m2 g–1 by using a top-lit-updraft method. Then, the microporous WCS biochar was directly mixed with an appropriate amount of ZnO nanoparticles and KOH as activating agents via a solvent-free physical blending route. After further activation at 900 °C, the resulted carbons possess both micropores and mesopores that were named as WCS multiporous carbons. The carbon yield of the prepared WCS multiporous carbons with high surface area in the range of 1175–1537 m2 g–1 is up to 50%. Furthermore, the micropore/mesopore surface area ratio can be simply tuned by controlling the ZnO content. For supercapacitor applications, the as-prepared WCS multiporous carbon electrodes showed high specific capacitance (128 F g–1 at 5 mV s–1) with a good retention rate at 500 mV s–1 scan rate (>60% compared to the capacitance at 5 mV s–1) and low Ohmic resistance in a 1.0 M LiClO4/PC electrolyte. In addition to the ZnO nanoparticles, CaCO3 nanoparticles with low environmental impact were also used to prepare the WCS multiporous carbons. The assembled supercapacitors also demonstrate high specific capacitance (102 F g–1 at 5 mV s–1) and good retention rate (∼70%).

Multiporous Carbon Encapsulated Ni Nanoparticles Promoting Glycerol Valorisation towards Hydrogenation against Rearrangement†

Summary of main observation and conclusionA dual‐templating method was used to synthesize a series of hierarchical carbon supports containing different proportions of spherical macropores (ca. 200 nm in diameter) and mesoporous channels (ca. 4 nm in diameter). These and some other conventional carbon materials were subsequently impregnated with Ni and tested for the conversion of glycerol. The hierarchical catalysts exhibited a significantly higher conversion (96%) and selectivity (77%) to 1,2‐propanediol, and the specificity selectivity coefficient (6.1) towards 1,2‐propanediol against lactic acid was three times higher than that observed over a conventional Ni/Cmicro catalyst (2.1). The enhanced performance of these materials, compared with the Ni nanoparticles supported on conventional carbon supports, was attributed to their high surface areas (> 1110 m2∙g−1) and large pore volumes (ca. 0.4 cm3∙g−1) permitting greater accessibility of substrate and/or intermediates to Ni active sites. Given that the concentration of accessible Ni sites in these materials is higher, a competitive benzilic‐acid‐rearrangement reaction to produce lactic acid was suppressed, leading to an enhanced hydrogenation selectivity to 1,2‐propanediol. This study evidences the potential benefits, which can be established from utilizing hierarchical support materials in the valorization of biomass.

A multiporous carbon family with superior stability, tunable electronic structures and amazing hydrogen storage capability.

The traditional view that natural allotropes are more stable than artificially synthesized structures is widely accepted. For instance, graphite and diamond are more energetically favorable than other new carbon allotropes no matter whether they are experimentally prepared or theoretically predicted. Surprisingly, we find that a family of multiporous carbon (N-diaphenes) could be thermodynamically more stable than natural diamond with the increase of its feature size parameter N. Multiporous N-diaphenes exhibit extremely strong anisotropic mechanical properties and their ideal strength linearly depends on the corresponding yield strain. Density functional theory (DFT) calculations reveal that the bandgap hierarchy of N-diaphenes is inherited from their precursors. In addition, N-diaphenes exhibit superior capability for hydrogen storage due to their large specific surface areas.

Fabrication of WO2/W@C core-shell nanospheres for voltammetric simultaneous determination of thymine and cytosine.

Pomegranate-like multicore WO2/W nanocrystals wrapped with layers of multiporous carbon were fabricated via carbonization of a copper(II)-organic framework host and a tungsten-based polyoxometalates guest, and subsequent etching off the metallic copper. The WO2/W@C core-shell nanospheres were employed to modify an electrode for the analysis ofthe DNA bases thymine (T) and cytosine (C) by differential pulse voltammetry. The WO2/W@C exhibited strongly increased oxidation signal of T and C. Under optimized conditions, the enhanced peak current represented excellent analytical performance for determination of T and C. This is attributed to the synergic effects of the porous multicore-shell microstructure and the use of tungsten-based materials with their excellent electrocatalytic activity for T and C, with typical peaks voltages near 1.26V and 1.44V. The calibration plots for T and C extend from 1 to 4000μM and from 1 to 3000μM, respectively, and both detection limits are 0.2μM. The method was successfully applied to the determination of T and C in spiked blood and urine samples, and the recoveries are form 97.3 to 105.0%. Graphic abstractCore-shell nanospheres of type WO2/W-carbon were prepared for highly sensitive simultaneous voltammetric determination of thymine and cytosine.

Metal-free multiporous carbon for electrochemical energy storage and electrocatalysis applications

An electrocatalytic and electrochemical energy storage study of biomass-derived metal-free carbon is carried out.

Hierarchically Multiporous Carbon Nanotube/Co3 O4 Composite as an Anode Material for High-Performance Lithium-Ion Batteries.

Carbon nanotubes (CNTs) and porous Co3 O4 nanorod (Co3 O4 p-NR) composites are self-assembled to form a hierarchical porous structure through a facile hydrothermal method to meet the requirements of long cycle life, high capacity, and excellent rate capability for next-generation lithium-ion batteries. CNTs are embedded in Co3 O4 p-NR clusters to form a 3D conductivity network, which reduces the transportation resistance of electrons and ions. Co3 O4 p-NRs are assembled from nanoparticles, which enlarge the contact area between electrode and electrolyte to provide more space to buffer the large volumetric changes associated with repeated electrochemical reactions and maintain the structural integrity. The obtained samples exhibit a high reversible capacity (1083 mA h g-1 after 140 cycles at 0.5 Ag-1 ), superior rate capability (521 mA h g-1 at 8 Ag-1 ), and excellent cyclic stability, with a capacity decay of 0.57 mA h g-1 per cycle at a high current of 1 Ag-1 over 200 cycles. The specific heterodimensional structure gives rise to a new approach to exploit high-performance electrode materials.

Robust Cage-Based Zinc–Organic Frameworks Derived Dual-Doped Carbon Materials for Supercapacitor

Electrochemical double layer capacitors can store electrical energy by accumulating electrolyte ions on the electrode surface and are playing an important role in renewable energy sources due to their high power density and superior durability. Owing to the excellent electrical, mechanical, and thermal characteristics, three-dimensional multiporous carbon nanomaterials are catching considerable attention which could lead to the high-rate supercapacitor performance. Here, we present a stable 1.7 nm cage-based metal–organic framework (BMM-9, [Zn2(TPO)4/3(dabco)·Solvent]) with high porosity of 62.4%. On the other hand, after the thermal treatment at high temperature, the three-dimensional MOF-derived micro/mesoporous carbon material BMM-9-900 acts as dual-doped active electrode materials and shows a capacitance of 182.8 F g–1 at a current density of 1 A g–1, and a capacity retention of 98.5% over 1000 cycles. Given the well-established structural tunability, these outcomes will shed light on a new generation...

Natural nitrogen-doped multiporous carbon from biological cells as sulfur stabilizers for lithium–sulfur batteries

In this context, we firstly synthesized a novel nitrogen-doped multiporous carbon material from renewable biological cells through a facile chemical activation with K2CO3. After sulfur impregnation, the carbon/sulfur composite achieved a sulfur content of about 67wt%. The C/S composite as the cathode of lithium–sulfur batteries exhibited a discharge capacity of 1410mAh/g and good capacity retention of 912mAh/g at 0.1C. These outstanding results were attributed to the synergy effect of microporous carbon and natural doping nitrogen atoms. We believe that the facile approach for the synthesis of nitrogen-doped multiporous carbon from the low-cost and sustainable biological resources will not only be applied in lithium–sulfur batteries, but also in other electrode materials.

Hydrothermal synthesis of manganese oxide encapsulated multiporous carbon nanofibers for supercapacitors

Hydrothermal carbonization (HTC) of biomass to produce one-dimensional carbon materials with hierarchical pores is of significant importance. Here, we fabricate composites of MnOx-encapsulated multiporous carbon nanofibers (M-MCNFs) from naturally available carbohydrates through a dopamine-assisted HTC/ templating process. The introduction of dopamine aids in the formation of the morphology of carbon nanofibers (CNFs) by enhancing the interactions between the hard-templates and carbohydrates. The chosen cryptomelane hard-templates, which are superior to traditional hard-templates, are converted into Mn3O4 nanoparticles embedded in multiporous CNFs (MCNFs), eliminating the need for tedious post deposition procedures to introduce redox active sites. Hence, the obtained hybrids with large surface areas, hierarchical pores, and unique structures show great potential in supercapacitors. This economic and sustainable strategy paves a new way for synthesizing MCNFs and metal oxide-encapsulated MCNFs composites from biomass.

Facile preparation and sulfidation analysis for activated multiporous carbon@NiCo2S4 nanostructure with enhanced supercapacitive properties

A facile two-step hydrothermal method is modified to synthesize NiCo2S4 nanosheets on activated multiporous carbon (AMC) for application in supercapacitors. The structure and performance of both NiCo2S4 and the intermediate product, i.e. NiCo2O4 on AMC are investigated in detail to clarify the effect of the sulfidation treatment. Owing to the high electronic conductivity of NiCo2S4, the unique designed nanostructure exhibits a high specific capacitance (651.1Fg−1 at 0.6Ag−1), good rate performance (88.1% retention for current increases around 17 times) and excellent cycling stability (87.4% retention after 2000 cycles). These results suggest this hybrid composite to be a promising electrode material for high-performance supercapacitors and the rational fabrication provides an approach to improve the electrochemical energy storage for other transition metal sulfides and oxides.