Hierarchical Porous Carbon Framework Research Articles

3D hierarchical porous N-doped carbon nanoarchitecture coated bimetallic phosphides as a highly efficient bifunctional electrocatalyst for overall water splitting

As the energy and ecological crises are increasingly grim, it is challengeable but extremely attractive to fabricate highly efficient and low-cost bifunctional electrocatalysts for overall water splitting (OWS). Herein, a bimetallic phosphide embedded in N-doped hierarchical porous carbon (CoP/Ni2P@NHPC) framework was successfully constructed by calcination and phosphorization of cobalt–nickel coordination polymer nanoflowers (Co/Ni CPNFs), which were obtained by a facile hydrothermal process. Benefitting from their fascinating architecture and composition, the as-prepared CoP/Ni2P@NHPC exhibits outstanding electrochemical properties for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) with small Tafel slopes (103.9 mV dec-1, 62.58 mV dec-1) and ultralow overpotentials (275 mV, 159 mV at 10 mA cm−2) in alkaline medium. Additionally, the CoP/Ni2P@NHPC can be used as a bifunctional catalyst in a two-electrode water splitting device, and it only requires a low cell voltage of 1.55 V to attain the current density of 10 mA cm−2. Meanwhile, the CoP/Ni2P@NHPC also present admirable durability (at least 20 h) under long-term electrolysis. This work gives inspiration for the preparation of highly active bifunctional electrocatalysts for OWS.

Design of Fe and N co-decorated biomass-derived hierarchical porous carbon frameworks with boosted oxidase-like activity for hydroquinone detection

An Fe and N co-decorated biomass-derived porous carbon framework with boosted oxidase-like activity was prepared and applied to sensitive hydroquinone detection.

Hierarchical porous carbon frameworks derived from Juncus effusus biomass with robust electromagnetic wave absorption properties

A biomass-derived electromagnetic absorber was developed using Juncus effusus (JE), achieving low RL value and broad EAB (−40.4 dB, 3.48 GHz), and the maximum RCS reduction value of 32.4 dB m2.

Controllable Preparation of a N-Doped Hierarchical Porous Carbon Framework Derived from ZIF-8 for Highly Efficient Capacitive Deionization.

Capacitive deionization (CDI) is a promising desalination technology, and metal-organic framework (MOF)-derived carbon as an electrode material has received more and more attention due to its designable structure. However, MOF-derived carbon materials with single-pore structures have been difficult to meet the technical needs of related fields. In this work, the ordered hierarchical porous carbon framework (OMCF) was prepared by the template method using zeolitic imidazolate frameworks-8 (ZIF-8) as a precursor. The pore structures, surface properties, electrochemical properties, and CDI performances of the OMCF were investigated and compared with the microporous carbon framework (MCF), also derived from ZIF-8. The results show that the hierarchical porous carbon OMCF possessed a higher specific surface area, better hydrophilic surface (with a contact angle of 13.45°), and higher specific capacitance and ion diffusion rate than those of the MCF, which made the OMCF exhibit excellent CDI performances. The adsorption capacity and salt adsorption rate of the OMCF in a 500 mg·L-1 NaCl solution at 1.2 V and a 20 mL·min-1 flow rate were 12.17 mg·g-1 and 3.34 mg·g-1·min-1, respectively, higher than those of the MCF. The deionization processes of the OMCF and MCF closely follow the pseudo-first-order kinetics, indicating the double-layer capacitance control. This work serves as a valuable reference for the CDI application of N-doped hierarchical porous carbon derived from MOFs.

MIL-53(Al) assisted in upcycling plastic bottle waste into nitrogen-doped hierarchical porous carbon for high-performance supercapacitors

Disposable aluminum cans and plastic bottles are common wastes found in modern societies. This article shows that they can be upcycled into functional materials, such as metal-organic frameworks and hierarchical porous carbon nanomaterials for high-value applications. Through a solvothermal method, used poly(ethylene terephthalate) bottles and aluminum cans are converted into MIL-53(Al). Subsequently, the as-prepared MIL-53(Al) can be further carbonized into a nitrogen-doped (4.52 at%) hierarchical porous carbon framework. With an optical amount of urea present during the carbonization process, the carbon nanomaterial of a high specific surface area of 1324 m2 g−1 with well-defined porosity can be achieved. These features allow the nitrogen-doped hierarchical porous carbon to perform impressively as the working electrode of supercapacitors, delivering a high specific capacitance of 355 F g−1 at 0.5 A g−1 in a three-electrode cell and exhibiting a high energy density of 20.1 Wh kg−1 at a power density of 225 W kg−1, while simultaneously maintaining 88.2% capacitance retention over 10,000 cycles in two-electrode system. This work demonstrates the possibility of upcycling wastes to obtain carbon-based high-performance supercapacitors.

Hard template synthesis of Zn, Co co-doping hierarchical porous carbon framework for stable Li metal anodes

Li metal is regarded as the most potential anode material due to the high energy density, low redox potential and high theoretical specific capacity. However, the development of the Li metal battery is seriously restricted by dendrite and huge volume change. In this paper, a hierarchical porous carbon framework with Zn/Co co-doping (PACF-ZC) is prepared by hard template method. Due to the combined action of different porous structures, the interior space provides sufficient reduction place for Li+ plating, when the Li+ flux uniformly disperses on the surface of PACF-ZC. So, the huge volume and growth of dendritic Li can be repressed by the distinctive hierarchical porous structure, effectively. In addition, the co-doping of Zn and Co reduces the nucleation barrier and promotes the Li affinity of PACF-ZC. The pyridine N and pyrrolidine N in precursor can optimize the behavior of Li+ plating. Benefit from the synergistic effect of hierarchical porous structure and Zn, Co co-doping, the symmetrical battery with Li@PACF-ZC obtains an ultra-long cycle life (1800 h) at 1 mA cm−2 with a capacity of 1 mAh cm−2. Meanwhile, the full cell of Li@PACF-ZC||LiFePO4 yields a high specific capacity of 128.8 mAh/g under 1C after 100 cycles.

Constructing Co/Fe-Nx dual-site catalyst based on Co0.72Fe0.28 alloy nanoparticles anchored on hollow hierarchical porous carbon framework for enhanced oxygen reduction reaction and ZABs

Hollow hierarchical porous nitrogen-doped carbon (HNC) derived from ZIF-8@ZIF-67 (ZIF: zeolitic-imidazolate framework) is a promising nanocomposite electrocatalyst rich in active sites. However, the single active species (Co-Nx) constrains its application. By introducing Fe in the precursor preparation, this work increased the active species of the catalyst to Co/Fe-Nx species and Co0.72Fe0.28 nanoparticles. Due to the advantages of abundant active sites and the synergy of multiple active species, Co,Fe-HNC-1 exhibited excellent oxygen reduction reaction (ORR) performance in 0.1 M KOH electrolyte with an onset potential (Eonset = 0.92 V vs. RHE) and a half-wave potential (E1/2 = 0.85 V vs. RHE) comparable to those of commercial Pt/C, as well as better long-term stability and methanol resistance. Meanwhile, Co,Fe-HNC-1 additionally demonstrated oxygen evolution reaction (OER) activity. Co,Fe-HNC-1 also performed well as an air cathode in a zinc-air battery (ZAB) with a peak power density of 85.00 mW cm-2 and outstanding stability with only 1.8 % loss after more than 200 galvanostatic cycles at 10 mA cm-2. This work provides a new perspective for the rational design and preparation of electrocatalysts based on HNC nanocomposites.

MOFs-derived hierarchical porous carbon supported Co@NC nanocapsules for pH universal oxygen reduction reaction and Zn-air batteries

The rational design and construction of the hierarchical porous structure of carbon framework to support transition metal-based catalysts is critical to increase their active sites density and facilitate mass/electron transport. Herein, we report a novel nanocapsules with cobalt core and nitrogen-doped carbon shells (Co@NC) supported on MOFs-derived hierarchical porous carbon framework. The rational hierarchical porous carbon framework with controllable size and micropore/mesoporous ratio was achieved by one-step pyrolysis of Zn(acac)2·phen ligand and ZIF-67 precursor, which is beneficial for the mass transport in the oxygen reduction reaction (ORR). The 0.4Co@NC-900 electrocatalyst display a distinguished ORR activity in the pH-universal range, with a half-wave potential of 0.91 V in alkaline and 0.76 V in acid electrolytes. The excellent ORR performance of our electrocatalyst can be attributed to its optimized micropore/mesoporous ratio of carbon framework with efficient mass transport, together with the graphitized carbon shell on Co nanoparticles which not only enhances the electron/proton transport, but also suppresses the chemical corrosion of the Co nanoparticles. Impressively, the Zinc-air battery as air electrode offers peak power density of 203 mW cm−2 and long-term stability of 130 h, showing an excellent battery performance. This study offers a fresh method of constructing ORR catalysts with increased activity and durability over a universal pH range.

Rapid and effective cycloaddition of environmentally diluted CO2 catalyzed by hierarchical porous ionic carbon at atmospheric conditions

From the perspective of environmental protection and sustainable development, the strategy of directly converting CO2 into high value-added chemicals is extremely strategic but still presents challenges in terms of efficient conversion of waste and diluted CO2. In this work, based on multilayer carbon materials, we prepared a variety of hierarchical porous ionic materials rich in ionic groups by introducing self-polymerizing functionalized positive charged delocalized ILs. These materials are utilized as recyclable heterogeneous catalysts for cycloaddition reactions between various epoxides and pure/dilute CO2 under mild conditions. Further research has revealed that the superior performance is attributed to the interesting synergistic effects, including hierarchical porous carbon frameworks, linear multi-nitrogen flexible ILs moieties as hydrogen bond donors (HBDs), and easy to leave halogen anions as nucleophiles. Furthermore, the results of XPS spectra and density functional theory (DFT) calculations suggest that positive charged delocalized ILs accelerate the reaction by providing strong hydrogen bonding effects and enhancing the nucleophilicity of halide anions. Moreover, it is found that the catalyst could maintain its activity after 5 cycles of experiments, which has a good application prospect.

Wood-derived density-adjustable hierarchical porous carbon frameworks for high-performance lithium-sulfur batteries

Lithium-sulfur batteries have the advantages of high specific capacity and low cost, but are subject to poor rate and cycle performance. In this work, we prepared wood-derived hierarchical porous free-standing carbon framework materials as three-dimensional conductive current collectors to assemble high-performance lithium-sulfur batteries. The micron-scale pores of wood are conducive to the diffusion of electrolyte, and the introduction of a large number of nanopores on the carbon skeleton can inhibit the dissolution and shuttle effect of lithium polysulfide, and improve the rate and cycle performance of the batteries. The porous carbon framework is density-adjustable and free-standing, and the battery has a specific capacity of 1120 mAh/g with good rate performance. The capacity decay are only 0.11%/cycle and 0.08%/cycle respectively under 0.5 C and 1 C after 500 cycles. In addition, wood is inexpensive and renewable, and the batteries are assembled without conventional conductive agents, binders and current collectors.

Biomass chitosan derived 3D hierarchical porous carbon framework: Green synthesis and efficient polysulfide confinement

In this study, we synthesize a nitrogen-doped hierarchical porous carbon framework with an ultrahigh surface area (a Brunauer-Emmett-Teller surface area of 2514.79 m2/g) rich in micropores/mesopores using a template-free strategy utilizing low-cost biomass chitosan as a precursor. This environmental-friendly non-organic potassium/lithium hydroxide system not only dissolves chitosan but also activates carbon framework. Moreover, rational pore structure and physical properties (e.g. conductivity) are realized by adjusting the heat-treatment temperature. The nitrogen-doped hierarchical porous carbon framework/S cathodes reach high area capacities of 4.02 mAh/cm2 and 6.02 mAh/cm2 at 0.2C with high sulfur loadings of 4 and 8 mg/cm2, which can be attributed to the immobilization of lithium polysulfide via micropores/mesopores combined with heteroatom doping. In-situ Raman and X-ray diffraction tests further confirm that the rich micropores/mesopores of the carbon host can act as an active site for the inhibition and catalytic conversion of polysulfide. It is a new strategy and direction for recycling biomass chitosan and also provides a reference for the practical and commercial large-scale application of lithium sulfur batteries.

N/O-doped porous carbon matrix for improved potassium-selenium battery cathode in different electrolyte systems

Combining the high abundance of potassium (K) in the Earth’s crust and the high theoretical energy density of selenium (Se), a potassium-selenium (K-Se) battery is attractive as an alternative energy storage system. However, some urgent issues still need to be solved to obtain efficient selenium-based cathodes, such as the shuttle effect of high-order selenides in electrolytes and volume expansion during the redox process. Herein, we report Se/heteroatoms (N and O) dual-doped hierarchical porous carbon (Se/HHPC) composite as cathode material for the K-Se battery. The hierarchical porous carbon frameworks not only provide storage and expansion buffer space for Se-based cathode material, but also facilitate the penetration of the electrolyte, which effectively improves the cell's electrical conductivity. In addition, the dual-doped heteroatoms enhance the interaction between potassium selenide and carbon host. When tested for K-ion batteries with carbonate electrolytes, Se/HHPC cathode exhibits a relatively high electrochemical performance (228 mAh g−1, 200 cycles, 0.2 C) under the synergy of space bondage and chemisorption. The electrode could deliver a rate capability of 295 mAh g−1 at 4 C. Furthermore, the hybrid cathode also exhibits excellent properties in ether electrolytes and has a reversible capacity of 236 mA h g−1 at 0.2 C after 300 cycles and a rate capability of 234 mAh g−1 at 4 C.

The Scalable Solid-State Synthesis of a Ni5P4/Ni2P-FeNi Alloy Encapsulated into a Hierarchical Porous Carbon Framework for Efficient Oxygen Evolution Reactions.

The exploration of high-performance and low-cost electrocatalysts towards the oxygen evolution reaction (OER) is essential for large-scale water/seawater splitting. Herein, we develop a strategy involving the in situ generation of a template and pore-former to encapsulate a Ni5P4/Ni2P heterojunction and dispersive FeNi alloy hybrid particles into a three-dimensional hierarchical porous graphitic carbon framework (labeled as Ni5P4/Ni2P–FeNi@C) via a room-temperature solid-state grinding and sodium-carbonate-assisted pyrolysis method. The synergistic effect of the components and the architecture provides a large surface area with a sufficient number of active sites and a hierarchical porous pathway for efficient electron transfer and mass diffusion. Furthermore, a graphitic carbon coating layer restrains the corrosion of alloy particles to boost the long-term durability of the catalyst. Consequently, the Ni5P4/Ni2P–FeNi@C catalyst exhibits extraordinary OER activity with a low overpotential of 242 mV (10 mA cm−2), outperforming the commercial RuO2 catalyst in 1 M KOH. Meanwhile, a scale-up of the Ni5P4/Ni2P–FeNi@C catalyst created by a ball-milling method displays a similar level of activity to the above grinding method. In 1 M KOH + seawater electrolyte, Ni5P4/Ni2P–FeNi@C also displays excellent stability; it can continuously operate for 160 h with a negligible potential increase of 2 mV. This work may provide a new avenue for facile mass production of an efficient electrocatalyst for water/seawater splitting and diverse other applications.

Capacitance-dominated hierarchical porous three-dimensional carbon framework enhanced Prussian blue analogue as superior cathode for sodium-ion batteries

The 3D framework carbon is an ideal host of active materials for energy storage batteries. In this work, KxNayMn[Fe(CN)6] (KNMF) nanocubes were in-situ grown on hierarchical porous 3D framework carbon (3DFC) to construct a composite cathode (KNMF@3DFC) for sodium-ion batteries. Owing to the hierarchical porous structure and large specific surface area, the highly conductive 3DFC offers abundant active sites for sodium storage and contributes to extra capacity. The considerable content of surface capacitance-dominated sodium storage of KNMF@3DFC composite cathode reveals faster charge transfer and better reaction kinetics, conducing to its rate capability. Ex-situ XRD/Raman measurements further reveal well structural stability of KNMF@3DFC during the whole cycle. Consequently, the KNMF@3DFC composite electrode reveals excellent rate performance and superior long-term cycling stability. Combining active materials with 3D framework carbon to enable a capacitance-dominated sodium storage mechanism is a promising strategy to stimulate the development of advanced electrode materials.

Fabrication of multi-purposed supercapacitors based on N-doped porous carbon framework

The development of versatile supercapacitors is becoming a new trend to meet the needs of different application scenarios, including high/low temperature and flexible features and so on. In this paper, wide-temperature range and flexible supercapacitors are constructed using hierarchical porous N-doped carbon framework (N-CF) and gel electrolyte, where N-CF is prepared via one-step pyrolysis of potassium citrate and anion exchange resin (AER) sol. Findings indicate that the porous structure and the specific surface area electrode materials play different roles in electrochemical performance of electrical double-layer capacitors (EDLCs). The coexistence of micropore and mesopore endows carbon materials with excellent performance including high specific capacitance (316 F g−1 at 1 A g−1) and rate capability (retention of 77 % from 1 to 100 A g−1). Moreover, pseudocapacitance coming from O-/N-containing function groups is estimated on the basis of cyclic voltammogram curves to explain the capacitance contribution. Additionally, polyvinyl alcohol (PVA)-based gel electrolyte is fabricated through low-temperature self-crosslinking by incorporating ethylene glycol/water (EG/H2O) binary solvent, which gives EDLCs a high energy density of 20.1 Wh kg−1 at power density of 0.45 kW kg−1 under 20 °C. Remarkably, the introduce of gel electrolyte can also make EDLCs low-temperature tolerant (a high energy density of 17.4 Wh kg−1 and excellent cycle stability under −20 °C), and wearable, which can meet the needs of different application scenes.

Hierarchical porous biomass-derived carbon framework with ultrahigh surface area for outstanding capacitance supercapacitor

A porous carbon framework is successfully synthesized from lycium chinensis via a novel strategy using melamine matched with KOH as dual-activator. The biomass-derived carbon framework with hierarchical macro-/meso-/micro pores demonstrates an ultrahigh surface area of 3344 m2 g−1 and a sufficient total pore volume of 1.71 cm3 g−1. The porous carbon electrode with optimized structure presents an outstanding electrochemical performance. The specific capacitance reaches 520.0 F g−1 at 1 A g−1 and 291.0 F g−1 at 30 A g−1 with 96.8 % capacitance retention after 10 000 cycles at 30 A g−1. The energy density is also as high as 12.5 W h kg−1 for the electrode. The relationship between optimized structure and excellent performance of carbon materials is deeply explored. The superior electrochemical performance of carbon framework can be ascribed to its hierarchical porosity, ultrahigh surface area, sufficient total pore volume, proper graphitization degree and favorable heteroatom-doping, which will result in the fast ion diffusion, sufficient charge storage as well as the contributed pseudocapacitance. The work provides an effective guidance for synthesizing the superb porous biomass-derived carbon materials for supercapacitor with high performance.

Constructing Precise Coordination of Nickel Active Sites on Hierarchical Porous Carbon Framework for Superior Oxygen Reduction.

Single-atom catalysts (SACs) with specific coordination environment are expected to be efficient electrocatalysts for oxygen reduction reaction (ORR). Herein, NiN4 C10 coordination site is constructed through encapsulating Ni2+ into the cavity of ZIF-8 as a self-sacrificing precursor and anchoring it on 3D N-doped carbon frameworks. The NiN4 C10 catalyst shows excellent ORR activity and stability, with a high half-wave potential (0.938V vs RHE), which is currently the best performances in Ni-based SACs. The remarkable performance with high ORR activity in alkaline solution is attributed to the single-atom nickel active sites with faster electron transport and suitable electronic structure. Moreover, the power density of zinc-air battery assembled by NiN4 C10 as cathode is 47.1% higher than that of the commercial Pt/C. This work not only provides a facile method to prepare extremely active Ni-based SACs, but also studies the intrinsic mechanism toward the oxygen reduction reaction under alkaline condition.

Biomass derived hierarchically porous carbon inherent structure as an effective metal free cathode for Li‐O2/air battery

AbstractA hierarchical porous carbon framework derived from betel‐nut is synthesized and employed as a bifunctional cathode in a Li‐O2/air battery. The prepared betel nut derived activated porous carbon (BNAPC) material exhibits an ordered and merged tube‐like porous morphology and a high specific surface area of 768 m2/g. The presence of both meso and micro porous leads to a well‐developed 3D interconnected carbon framework, which provides an efficient path for the diffusion of the reactant (oxygen as well as air) and also allows stocking the discharge product of Li2O2. Therefore, it exhibits a high specific capacity and excellent rate performance. A maximum discharge capacity of 9560 and 2000 mAh/g at a current density of 100 mA/g for oxygen and ambient air respectively as the reactant is achieved. The prepared material also exhibits reversible cyclic stability of 27 cycles with a specific capacity of 1000 mAh/g at a 100 mA/g current density in oxygen atmosphere.

Investigation of MOF-derived humidity-proof hierarchical porous carbon frameworks as highly-selective toluene absorbents and sensing materials

Carbon frameworks (CFs) derived from metal-organic frameworks (MOFs) have been produced as adsorbents of toluene. To further obtain optimum hierarchical porous carbon structure of CFs, different treatment temperatures were applied to a typical kind of MOFs (ZIF-8). The adsorption capacity of the toluene of hierarchical porous CFs obtained from ZIF-8 under 1100 °C (CF-1100, adsorption capacity of 208.5 mg/g) was higher than that of other carbonization temperature and MOFs. Impressively, the adsorbent CF-1100 also exhibited strong hydrophobicity, low desorption temperature, and good selectivity to toluene. The adsorption capacity decreased by only 10.4% under wet condition compared with the dry condition, standing on the top of the recently reported adsorbents. The impressive adsorption performance of CF-1100 is attributed to the larger specific surface area (1024 m2/g) and pore volume (0.497 cm3/g), newly generated micropores (pore width is 0.6–0.8 nm) and mesopores (pore width above 10 nm), and carbonaceous structure with higher degree of graphitization. Based on the adequate adsorption performance, CF-1100 coated quartz crystal microbalances as sensor also showed a high sensitivity of 0.4004 Hz/ppm and small relative standard deviations of 1.0745% for toluene sensing. This contribution provides a foundation for optimizing potential adsorbents and sensing materials for air pollution abatement.

Promoting sulphur conversion chemistry with tri-modal porous N, O-codoped carbon for stable Li–S batteries

A tri-modal hierarchical porous carbon framework with N, O dual heteroatom doping is designed and prepared. The synergy between optimized pore size distribution and efficient surface-chemistry confinement of sulfur resulted in quick redox kinetics of lithium polysulfides.