Hierarchical Nanoporous Carbon Research Articles

Hierarchical Nanoporous N-Doped Carbon for Enhanced Rate Performance of Lithium-Ion Battery Anodes

Hierarchical Nanoporous N-Doped Carbon for Enhanced Rate Performance of Lithium-Ion Battery Anodes

Ultra-high Capture of Radioiodine With Zinc Oxide-decorated, Nitrogendoped Hierarchical Nanoporous Carbon Derived From Sonicated ZIF-8-Precursor

Ultra-high Capture of Radioiodine With Zinc Oxide-decorated, Nitrogendoped Hierarchical Nanoporous Carbon Derived From Sonicated ZIF-8-Precursor

Conducting co-polymer derived N, S co-doped metal-free hierarchical nanoporous carbon for robust electrochemical capacitor

The present investigation reported metal-free hierarchical porous and robust Nitrogen (N), Sulphur (S) co-doped carbon (NS-CoP@C) electrode for supercapacitor application. The NS-CoP@C was synthesized by single-step carbonization and activation of thiourea co-doped aniline-pyrrole co-polymer (CoP). The thiourea acted as a doping as well as activating agent. The data of three different electrode materials PANI-PPy co-polymer (CoP), PANI-PPy co-polymer derived Carbon (CoP@C) and N, S co-doped carbon derived from PANI-PPy co-polymer (NS-CoP@C) are compared in the present report. The electrode materials were initially characterized by various spectroscopic techniques. It is observed that among the three electrode material, NS-CoP@C possess higher specific surface area (SSA), high pore volume and hierarchal porous structure with a better mesopore-to-micropore volume ratio. In a three-electrode system, NS-CoP@C possesses a high specific capacitance of 344.2 F/g @ 0.5A/g. Moreover, NS-CoP@C electrode was used to fabricate an all solid-state (PVA-1 M H2SO4 polymer gel electrolyte) and aqueous (1 M H2SO4 electrolyte) symmetrical supercapacitor devices in the two-electrode system. This NS-CoP@C electrode was used as both positive and negative electrode material in both types of devices. Among them, the solid-state device operates at a wide potential window of 2 V, as a consequence delivering an implausible energy and power density of 45.25 Wh/kg and 1025.64 W/kg while maintaining a capacity retention of 90.1 % even after 8500 charge-discharge cycles. Hence, the excellent performance of conducting PANI-PPy co-polymer-derived N, S co-doped carbon paved new ground for developing an alternative electrode for futuristic energy storage devices.

Oxygen-Enriched Hierarchical Nanoporous Carbon Electrodes for Supercapacitors

Enhancing the energy storage capacity of carbon electrodes is a key challenge to developing high-performance supercapacitors. In this study, we design an oxygen-enriched hierarchical nanoporous carbon electrode using laser fabrication and subsequent electrochemical activation, which demonstrates superior energy storage capacity. The carbon electrode is first obtained through the carbonization of phenolic resin under instantaneous high temperature induced by laser, resulting in multiple ion transport channels and a specific capacitance of 64.17 mF cm–2 at the current density of 0.2 mA cm–2. To further improve the performance, electrochemical activation is successfully conducted, leading to a 12.1-fold increase of the specific capacitance of the carbon electrodes. It is found that O–C═O-containing functional groups formed during the activation process significantly contribute to the high capacitance enhancement. In a 1 M H2SO4 electrolyte, the activated hierarchical nanoporous carbon electrode delivers a high specific capacitance of 778.3 mF cm–2 under the same test conditions. Additionally, the abundant porous structure and excellent reversibility of redox reaction of the oxygen-containing functional groups enable the assembled supercapacitor to obtain a specific capacitance of 45.3 mF cm–2 at the current density of 0.4 mA cm–2 and maintain a capacitance retention rate of 93.6% after 10,000 charge–discharge tests. This study presents a strategy to prepare carbon electrode materials with both high performance and excellent stability.

MOF-derived hierarchical carbon/ZnO hybrid synergistically boosts photothermal conversion and storage capability of phase change materials

The weak photon-capturing ability is a long-standing bottleneck for pristine metal–organic framework (MOF)-based phase change materials (PCMs) in photothermal conversion and latent heat storage applications. Herein, we designed MOF-5-derived hierarchical nanoporous carbon/ZnO nanoparticle hybrid as dual efficient photonic harvester and molecular heater for synergistically boosting photothermal conversion and storage capability of PCMs using an in-situ anchoring strategy. Compared with post-decorated ZnO strategy, ZnO photosensitizers derived in situ from MOF-5 are capable of guaranteeing high dispersibility and enhanced photon-capturing capability in the hierarchical carbon framework. Resultantly, high-performance photothermal composite PCMs are obtained due to the constructed intense and broadband absorption photonic nanoheaters after paraffin wax (PW) is encapsulated inside MOF-5-derived hierarchical nanoporous carbon/ZnO (MOF-5-PC/ZnO). Benefiting from the synergistic effect of dual high-efficiency photonic harvester and molecular heater (MOF-5-derived ZnO nanoparticles and hierarchical nanoporous carbon), PW@MOF-5-PC/ZnO-700 °C composite PCMs obtain the optimal photothermal conversion and storage capacity. Meanwhile, PW@MOF-5-PC/ZnO composite PCMs exhibit superior shape stability, thermal stability, and durable reliability. Importantly, our proposed development strategy of high-efficiency photothermal composite PCMs is universal due to high customization and universality of PCMs and Zn-MOFs.

Effects of activation parameters on Zeolitic imidazolate framework JUC-160-derived, nitrogen-doped hierarchical nanoporous carbon and its volatile iodine capture properties

Despite its importance in the nuclear industry, the uncontrollable use and/or accidental release of iodine in the environment pose serious threats to human health and endanger wildlife. Therefore, effective removal of radioiodine from various environmental media is necessary to circumvent its adverse effect. Herein, we report on an excellent and highly efficient capture of iodine by ZIF (JUC-160)-derived ultra-porous carbon. The ultra-porous carbon, obtained through KOH activation at high temperature, displayed unprecedented iodine capture properties with uptake capacities of 1567 mg g−1 and 821 wt.% in the aqueous and vapor phases, respectively. Various conditions including activation temperature and residency time effects on material properties and uptake performances were evaluated. The results showed that iodine uptake increased with increasing activation temperature; while activation time beyond 60 min was not favorable because the carbon materials were completely gasified. Kinetics and Isotherm fitting with the experimental data was done to assess sorption behavior of the derived carbon materials and their interactions with iodine. The results showed that chemisorption was the dominant medium through which iodine was captured as confirmed by both pseudo-second order and Langmuir models. Furthermore, the main mechanism involved in the process was mainly attributed to electron donor-acceptor interactions wherein the oxygen-containing functional groups and nitrogen active sorption sites of the carbon materials acted as electron donors. This work provides insight into optimizing KOH activation temperature and residency time for best performance of iodine adsorbents.

Binary active sites of nickel–iron alloy bonded in nitrogen-doped carbon nanocage for robust durability and low polarization zinc-air batteries

The industrialization of rechargeable metal-air batteries, especially zinc-air batteries (ZABs), is greatly limited to the low efficiency, high polarization, and short lifetime of oxygen catalysts (both oxygen reduction reaction and oxygen evolution reaction), which still faces challenges. Herein, a novel efficient bifunctional electrocatalyst based on binary active sites engineering of NiFe alloy embedded in hierarchical nanoporous nitrogen-doped carbon nanocage (NiFe@NC) is successfully synthetized by pyrolysis of urea and Prussian blue analogues coated with polydopamine. Profiting from strong synergetic between NiFe alloy and nitrogen-doped carbon, abundant Fe/Ni–N–C bond, this unique hierarchical yolk-core-shell structure provides an integration of superior OER and ORR property, half-wave potential of 0.86 V for ORR and a small overpotential of 277 mV at 10 mA cm−2 for OER in O2-saturated 0.1 M KOH. Consequently, the liquid ZABs based on the electrocatalyst exhibits a high open-circuit voltage of 1.50 V, a low-polarization voltage of 0.68 V after 370 h at 10 mA cm−2, as well as superior stability for up to 750 h (10 mA cm−2) and 450 h (20 mA cm−2). This work provides a reference significance to the research and development of high-performance rechargeable ZAB catalysts.

Hierarchical nano-porous carbon from semi-coke via a MgO template preparation strategy for ONP adsorption

O-Nitrophenol(ONP) industrial wastewater causes serious harm to human body and aquatic environment. In this paper, we adopted a recycled MgO template preparation strategy to design series of semicoke derived hierarchical porous carbons. The prepared samples were characterized by N2 adsorption and desorption and scanning electron microscope. The analysis showed that the HPC-1 had a high specific surface area of 723.3m2/g with a huge pore volume of 1.64 cm3/g and exhibited remarkable adsorption capacity of 503.02 mg/g in batch adsorption test for ONP. Adsorption isotherms and adsorption kinetics revealed the adsorption mechanism of ONP molecules on HPCs surfaces, which followed the langmuir monolayer adsorption and pseudo-second-order kinetic. Furthermore, the HPC-1 exhibited good reusability and recycling performance, reflecting its great potential in practical application.

Bio-inspired hierarchical nanoporous carbon derived from water spinach for high-performance supercapacitor electrode materials.

Due to various properties, green carbon nanomaterials with high specific surface area and environmentally friendly features have aroused extensive interest in energy storage device applications. Here, we report a facile, one-step carbonization of water spinach to synthesize porous carbon that exhibits a high specific surface area of ∼1559 m2 g−1, high specific capacitance (∼1191 F g−1 at 1 A g−1), a low intercept (0.9 Ω), outstanding rate capability and superior cycling stability (94.3% capacitance retention after 10 000 cycles). Moreover, the assembled symmetric cell delivers a high energy density of ∼85 W h kg−1 at 1200 W kg−1 and ultra-high stability (loss of 6.8% after 10 000 cycles). An energy density of 49 W h kg−1 could also be achieved even with a power density of up to 24 kW kg−1, which indicates that this material could be a promising candidate for future applications in aqueous-based supercapacitors.

Morphology controllable synthesis of heteroatoms-doped carbon materials for high-performance flexible supercapacitor

The biomass-based carbon materials with heteroatomic regulation, hierarchical structure, remarkable porosity, excellent conductivity and good stability are promising energy materials for supercapacitors. Herein, we designed and synthesized the multidimensional morphology controllable carbon materials by activation approach using pervasive watermelon rind as the carbon source. Interestingly, the carbon materials revealed diverse dimensional morphology characterizations for 3D hierarchical honeycomb nanoporous carbon architecture (CNP), 2D carbon nanoflake model (CNF) and 1D needle-shaped carbon nanobars (CNB) with/without different dopants. The CNB energy material indicated a large specific area for 879.18 m2 g−1, and the flexible electrode showed excellent areal capacitance for ∼2245 F cm−2 at 1 mA cm−2. Moreover, the constructed flexible symmetric device shows outstanding cycling stability for 99.5% after 20,000 cycles, superior energy density for 0.12 mWh cm−2 at a power density of 0.52 mW cm−2. This work provides a facile and sustainable approach to synthesize high-performance energy materials for supercapacitor.

Ultrahigh capture of radioiodine with zinc oxide-decorated, nitrogen-doped hierarchical nanoporous carbon derived from sonicated ZIF-8-precursor

The importance of iodine to industry and humans cannot be overemphasized. It plays a crucial role in human metabolic processes. It is widely used for various applications in medicine, material sciences, environmental, and engineering sciences. During the deployment of nuclear technology, there is release of radioiodine in the environment through processes such as reprocessing of nuclear fuel and accidents. Thus, to safeguard the applications of iodine and prevent the leakage of radioiodine into the environment, the capturing and storage of radioiodine are very critical. In our work, ultrahigh radioiodine adsorption capacities of 454 wt% and 1508 mg g−1 were achieved for iodine vapor and iodine in cyclohexane solution, respectively; using Zinc oxide and nitrogen-doped hierarchical porous carbon (ZnO@NCs), which has a surface area of 1983 m2g−1 synthesized by ultra-sonication of ZIF-8 precursor. These ultrahigh adsorption capacities could be the result of large pore volume of the pores and area of the surface; as well as the electron donor groups such as OH− and O2−, which generated charge transfer between iodine and the adsorbent. The adsorption fits the Freundlich and pseudo-second-order models. These large surface area, ultrahigh adsorption capacity, easy preparation, and good regeneration are indicative of ZnO@NCs as a promising radioiodine adsorbent.

Hierarchical Porous Carbon Electrodes with Sponge-Like Edge Structures for the Sensitive Electrochemical Detection of Heavy Metals.

This article presents the development of a highly sensitive electrochemical heavy metal sensor based on hierarchical porous carbon electrodes with sponge-like edge structures. Micrometer-scale hierarchical nanoporous carbon electrodes were fabricated at a wafer-scale using cost-effective batch microfabrication technologies, including the carbon microelectromechanical systems technology and oxygen plasma etching. The sponge-like hierarchical porous structure and sub-micrometer edges of the nanoporous carbon electrodes facilitate fast electron transfer rate and large active sites, leading to the efficient formation of dense heavy metal alloy particles of small sizes during the preconcentration step. This enhanced the peak current response during the square wave anodic stripping voltammetry, enabling the detection of Cd(II) and Pb(II) at concentrations as low as 0.41 and 0.7 μg L−1, respectively, with high sensitivity per unit sensing area (Cd: 109.45 nA μg−1 L mm−2, Pb: 100.37 nA μg−1 L mm−2).

A Non-volatile View of Site-Specific Adsorption and Dynamics of VOCs and CO2

Molecular adsorption—the process in which small molecules adhere to a surface—typically considers homogeneous, atomistically continuous, flat geometries. In this issue of Matter, Reimer and colleagues tackle a much more complex situation of volatile organic compounds and carbon dioxide on hierarchical nanoporous carbon with multiscale pores, resolving and characterizing phase-dependent site-specific dynamics via nuclear magnetic resonance (NMR).

Revealing Molecular Mechanisms in Hierarchical Nanoporous Carbon via Nuclear Magnetic Resonance

Author(s): Mao, H; Tang, J; Xu, J; Peng, Y; Chen, J; Wu, B; Jiang, Y; Hou, K; Chen, S; Wang, J; Lee, HR; Halat, DM; Zhang, B; Chen, W; Plantz, AZ; Lu, Z; Cui, Y; Reimer, JA | Abstract: Hierarchical nanoporous carbons combining pore sizes of different length scales are highly important for separation processes. However, critical questions remain regarding the hierarchical structure regulation and the molecular mechanisms of gaseous adsorbate uptake and interactions within the hierarchical nanoporous carbons. These materials present characterization challenges in that there are no experimental techniques that can elucidate the molecular mechanisms of the organic compounds and CO within the materials. We deployed multidimensional solid-state nuclear magnetic resonance (NMR) to generate maps of guest-framework interactions as a function of adsorbate concentrations and adsorption times. The NMR spectra provide insight toward the design of effective hierarchical pore structures. Our materials show a high volatile organic compounds/CO physisorption capacity, which reveals promising application to carbon-capture strategies to mitigate global warming. 2 2

Silver and Graphenic Carbon Nanostructures Differentially Influence the Morphology and Viability of Cardiac Progenitor Cells.

The characteristic features of nanomaterials provide rich opportunities for a broad range of applications due to their different physicochemical properties. Nanocolloidal silver and graphenic carbon materials differ in most physicochemical characteristics, except for their nanodimensions. Since there is a growing demand for stem cell therapies for coronary disorders, examining cardiac progenitor cells (CPC) in terms of their response to nanostructure treatment seems to be a reasonable approach. Morphological studies and viability assessments were performed with CPC in vitro, treated with small concentrations of silver nanoparticles (AgNP), hierarchical nanoporous graphenic carbon (HNC) and their mixtures. A viability test confirmed the morphological assessment of CPC treated with AgNP and HNC; moreover, the action of both nanomaterials was time-dependent and dose-dependent. For AgNP, between the two of the applied concentrations lies a border between their potential beneficial effect and toxicity. For HNC, at a lower concentration, strong stimulation of cell viability was noted, whereas a higher dosage activated their differentiation. It is necessary to perform further research examining the mechanisms of the action of AgNP and especially of unexplored HNC, and their mixtures, on CPC and other cells.

Membrane and electrode engineering of high-performance lithium-sulfur batteries modified by stereotaxically-constructed graphene

Lithium-sulfur batteries have great potential as the next-generation clean energy storage systems due to their remarkable high-energy density and electrochemical capacity. Additionally, sulfur is used as a cathode material because of its characteristics of a low cost, environmental friendliness, and abundant nature. However, the polysulfide shuttle effect decreases the electrochemical performance of lithium-sulfur batteries. Here, a rational membrane/electrode design has been applied to lithium-sulfur batteries. A three-dimensional hierarchical nanoporous carbon material derived from cationic resins in a cost-effective process was synthesized at a high temperature and utilized as an intermediate layer to improve the rate capability and cycle stability of lithium-sulfur batteries. Furthermore, stereotaxically -constructed multiporous graphene with a high conductivity (1.6 × 10 3 S m −1 ), porosity and large specific surface area (824 m 2 g −1 ) has been applied in the cathode to increase the conductivity of sulfur, improve the transport of lithium-ions and increase the contact with the electrolyte. In particular, stereotaxically-constructed multiporous graphene was used as the sulfur carrier (sulfur loading 70 wt %). The electrochemical results revealed an initial discharge capacity of the hierarchical nanoporous carbon material intermediate layer-coated membrane of 1008 mAh g −1 at 0.5C, and the reversible capacity was 532 mAh g −1 at 1C after 300 cycles. Based on the experimental evidence and analyses, we concluded that the enhanced performance is due to the confinement of lithium polysulfides by the micropores and mesoporous structure of the hierarchical porous carbon material and the increased transportation of lithium ions and the improved wettability of membrane by electrolyte. • Hierarchical nanoporous carbon material (HNCM) has been synthesized at a high temperature by a cost-effective process. • The HNCM reduce the interfacial resistance and increase the wettability of membrane by electrolyte. • The stereotaxically-constructed multiporous graphene (SCMG) employed as sulfur host for Li–S batteries. • The resultant lithium-sulfur batteries exhibit a superior rate capacity and improved cycling capacity. • The multiple physical sorption of the modified layer greatly inhibit the shuttling of polysulfide.

NiPt Nanoparticles Anchored onto Hierarchical Nanoporous N-Doped Carbon as an Efficient Catalyst for Hydrogen Generation from Hydrazine Monohydrate.

Catalytic decomposition of the hydrogen-rich hydrazine monohydrate (N2H4·H2O) represents a promising hydrogen storage/production technology. A rational design of advanced N2H4·H2O decomposition catalysts requires an overall consideration of intrinsic activity, number, and accessibility of active sites. We herein report the synthesis of a hierarchically nanostructured NiPt/N-doped carbon catalyst using a three-step method that can simultaneously address these issues. The chelation of metal precursors with polydopamine and thermolysis of the resulting complexes under reductive atmosphere resulted in a concurrent formation of N-doped carbon substrate and catalytically active NiPt alloy nanoparticles. Thanks to the usage of a silica nanosphere template and dopamine precursor, the N-doped carbon substrate possesses a hierarchical macroporous-mesoporous architecture. This, together with the uniform dispersion of tiny NiPt nanoparticles on the carbon substrate, offers opportunity for creating abundant and accessible active sites. Benefiting from these favorable attributes, the NiPt/N-doped carbon catalyst enables a complete and rapid hydrogen production from alkaline N2H4·H2O solution with a rate of 1602 h-1 at 50 °C, which outperforms most existing catalysts for N2H4·H2O decomposition.

High-performance asymmetric supercapacitors realized by copper cobalt sulfide crumpled nanoflower and N, F co-doped hierarchical nanoporous carbon polyhedron

Supercapacitors trigger tremendous interests in energy storage and conversion as they can safely provide high power density with long cycle life. However, the energy density of current supercapacitors is still restrained by microstructures and sluggish kinetics of electrode materials. Recently, zeolitic imidazolate frameworks (ZIFs) with excellent structural flexibility are demonstrated as one of promising precursors and templates to design novel supercapacitor electrode materials with high specific area and rich redox active sites. This work presents a systematic study of synthesis and characterizations of single ZIF-67-derived mesoporous copper cobalt sulfide (CuCo2S4) crumpled nanoflower and N, F co-doped hierarchical nanoporous carbon polyhedron (NFHPC). The obtained CuCo2S4 and NFHPC show superior capacitive performance due to abundant Faradic-redox active sites, efficient charge transport and excellent interfacial wettability. We further assemble an asymmetric supercapacitor based on CuCo2S4 as positive electrode and NFHPC as negative electrode. As a result, the assembled asymmetric supercapacitor achieves a high energy density of 55.1 Wh kg−1 at a power density of 799.8 W kg−1, and a long cycle life (91.1% of the initial capacitance after 5000 cycles). Our work thus provides an easy strategy to design effective electrode materials with superior performance for energy storage.

Guided Assembly of Well-Defined Hierarchical Nanoporous Polymers by Lewis Acid-Base Interactions.

Three-dimensional hierarchical nanoporous polymers and carbon nanomaterials with well-defined superstructures are of great interest for various intelligent applications, whereas a facile and versatile approach to access those materials with a high surface area, stable well-defined morphology, and ordered pores still remains a significant challenge. Herein, we report a self-regulated Lewis acid-base interaction-mediated assembly strategy for the in situ synthesis of morphology-engineered hyper-cross-linked porous polymers and carbon materials. A series of functionalized aromatic compounds (FAC) is subjected to self-cross-linking via classic Friedel-Crafts chemistry to achieve stable porous polymers with a high surface area. Varying the monomer/catalyst combination had a dramatic effect on the acid-base interaction, facilitating the tailoring of the self-assembled morphologies from nanotubes to hollow nanospheres, and even nanosheets. A mechanistic study showed that the byproducts generated during cross-linking orchestrate the interactions between the catalyst (acid) and FAC (base) and simultaneously drive the self-assembly to yield specific morphologies. Based on the rigid hollow polymer framework and intrinsic hydroxyl functionality, the hyper-cross-linked hollow nanospheres were easily transformed to an acid-functionalized catalyst for efficient biodiesel production. Moreover, high-quality porous carbonaceous nanocounterparts such as carbon nanotubes, hollow carbon nanospheres, and carbon nanosheets could also be produced by direct pyrolysis of the corresponding polymer precursors. These findings may provide guidance for the facile design of morphology-controlled functionalized polymers and carbon nanomaterials for various applications.

Hierarchical Nanoporous Carbon Templated and Catalyzed by the Bicontinuous Nanoporous Copper for High Performance Electrochemical Capacitors

AbstractTo enhance the performance of electrochemical capacitor, the nanostructured carbon materials with large surface area, appropriate pore distributions, suitable electronic conductivity and perfect chemical stability are pursued. Herein, the highly graphitized hierarchical porous carbon with well‐defined porosity are fabricated. For the first time, the novel bicontinuous nanoporous copper is used as both the template and the catalyst to synthesize the porous carbon materials. The as‐prepared porous carbon demonstrates a high specific surface area of 1826 m2 g−1 benefitting from the bicontinuous nanoporous copper template and KOH activation. By electrochemical test, the nanoporous carbon material displays a specific capacitance of 210 F g−1 at a current density of 0.2 A g−1 within 6 M KOH aqueous solution. The material demonstrates excellent cycling stability with a 95.4% capacity retention for 10 000 cycles with a current density of 1 A g−1. The present work provides a facile approach for fabrication of carbon‐based electrode materials for electrochemical capacitors.