N-doped Porous Carbon Framework Research Articles

Construction of honeycomb-like N-doped porous carbon framework with effective aperture distribution toward advanced supercapacitors and sodium-ion batteries

Smart synthesis of porous carbon with appropriate aperture distribution and high area utilization still retains an enormous challenge for efficient charge storage. Herein, a simple freeze-drying along with subsequent one-step carbonization/activation process is ingeniously devised to fabricate honeycomb-like nitrogen-doped porous carbon (NPC) framework with high-level active N/O-functional groups and hierarchical porous structure including substantial ultra-micropores (<0.7 nm). The underlying formation mechanism of such porous NPC framework is tentatively proposed. By finely regulating the dosage of NaHCO3, the optimized NPC (i.e., NPC114) is endowed with ultra-high surface area utilization of ∼26.4 μF cm−2 at 1 A/g in KOH electrolyte, which is close to theoretical value of electrochemical double-layer capacitance (15–25 μF cm−2), and even larger than the case (∼22.4 μF cm−2) with H2SO4 electrolyte due to the inaccessible ultra-micropores by SO42− of larger size. Similarly, as for the organic system, the as-prepared NPC115 with higher meso- and macropore surface area exhibits higher energy density of 22.36 Wh kg−1 than other counterparts. Furthermore, NPC114, when evaluated as anode material for sodium-ion batteries, exhibited more attractive high-rate Na+-storage properties as well. The in-depth understanding into intrinsic relationship between aperture distribution and electrochemical behaviors will provide meaningful guidance for electrode material design

Facilely Fabricating F-Doped Fe3N Nanoellipsoids Grown on 3D N-Doped Porous Carbon Framework as a Preeminent Negative Material.

Transition metal nitride negative electrode materials with a high capacity and electronic conduction are still troubled by the large volume change in the discharging procedure and the low lithium ion diffusion rate. Synthesizing the composite material of F-doped Fe3N and an N-doped porous carbon framework will overcome the foregoing troubles and effectuate a preeminent electrochemical performance. In this study, we created a simple route to obtain the composite of F-doped Fe3N nanoellipsoids and a 3D N-doped porous carbon framework under non-ammonia atmosphere conditions. Integrating the F-doped Fe3N nanoellipsoids with an N-doped porous carbon framework can immensely repress the problem of volume expansion but also substantially elevate the lithium ion diffusion rate. When utilized as a negative electrode for lithium-ion batteries, this composite bespeaks a stellar operational life and rate capability, releasing a tempting capacity of 574 mAh g-1 after 550 cycles at 1.0 A g-1. The results of this study will profoundly promote the evolution and application of transition metal nitrides in batteries.

Zinc sulfide quantum dots modified 3D Nitrogen-Doped framework carbon enhances the ion transport rate of potassium ion hybrid capacitors

The potassium-ion hybrid capacitor (PIHC) has garnered considerable attention due to its ability to leverage the advantages of both battery-type anodes and capacitor-type cathodes simultaneously. Nevertheless, the slow K+ transfer rate between the PIHC battery-type anode and capacitor-type cathode significantly impedes the overall performance. Herein, we have employed quantum-sized zinc sulfide (ZnS) immobilized within a three-dimensional N-doped porous carbon framework (ZnSQDS@3DNC) as a standalone anode. The corresponding three-dimensional N-doped porous carbon (3DNC) serves as the cathode, thereby constructing a PIHC device. The strong coupling between ZnS quantum dots and N-doped three-dimensional porous carbon material effectively enhances ion/electron transport, facilitating intercalation-conversion-exfoliation reactions and improving K+ transfer rates. The numerous active sites within the 3DNC significantly enhance the capacitance performance of the cathode, facilitating the reversible adsorption and desorption of FSI-. The values of DK+ have all been calculated to be within the range of 10-10 to 10-9 cm2 s−1, indicating the rapid diffusion capability of this ZnSQDs@3DNC structure. More impressively, the assembled PIHC device can achieve high energy densities of 179.9 Wh kg−1 at power densities of 200 W kg−1, with an ultralong cycling life over 10,000 cycles. This study serves to advance the development of metal-ion hybrid capacitors and provides direction for improving ion transport kinetics.

Structural construction of Bi-anchored honeycomb N-doped porous carbon catalyst for efficient CO2 conversion

Electrocatalytic CO2 reduction reaction (CO2RR) technology has attracted extensive attention owing to mild reaction conditions, high energy conversion efficiency, and facile adaptability. However, it remains a great challenge for the lack of highly active catalysts and the selectivity of reduction products. Herein, we successfully fabricated the Bi nanoparticles diffused in nitrogen-doped carbon frame catalysts (Bi@NCFs) by an in-situ pyrolysis process. The electrocatalytic test results demonstrate that the Faradaic efficiency of formate (FEHCOOH) of Bi@NCFs catalyst is higher than 79% in the potential range of −0.8～-1.3 V vs. RHE, of which FEHCOOH is as high as 95.70% at −1.0 V vs. RHE. After 48 h stability test, the FEHCOOH still preserves over 81.3%, indicating excellent durability and stability of the catalyst in H-cell. The synergistic effect between the honeycomb-like porous carbon framework and Bi NPs enhance the electrocatalytic activity of the catalyst; on the other hand, nano-scale Bi particles exist on the surface and inside of the porous carbon framework, increasing the active sites for CO2RR. Even under high current in the flow cell, the catalyst exhibits high formic acid selectivity and DFT calculation proves the superiority of formic acid generation. This work provides insights into synthesizing N-doped porous carbon framework supported nano-metal catalysts for CO2RR.

Facile Construction of Nano-Dimensional Bi Encapsulated in N-Doped Porous Carbon Frameworks for High-Performance Sodium-Ion Hybrid Capacitors

As a promising anode candidate for sodium storage, the adhibition of metallic Bi is limited by severe volume expansion and modest conductivity. To solve the issues, optimizing and designing both structures and compositions of Bi-based anodes are highly necessary. Herein, Bi nanoparticles encapsulated in N-doped porous carbon frameworks (Bi@NPC) are synthesized via a facile but efficient chemical blowing method. The size and dispersion of Bi NPs in the interconnected carbon frameworks are accurately adjusted through the control of reaction temperatures and nitrogen doping. Thanks to its attractive structural/componential merits, the optimized Bi@NPC anode shows that an excellent high-rate capability of 207.6 mA h g–1 is achieved at a high rate of 50 A g–1. In addition, it can still present a stable reversible capacity of 243.9 mA h g–1 over 2000 cycles at 10 A g–1. Furthermore, the assembled sodium-ion hybrid capacitors with Bi@NPC as the anode and commercial active carbon as the cathode realize an exceptional energy/power density of 94.2 W h kg–1/200 W kg–1 and a low capacity decay rate of 0.014% per cycle for 2400 cycles at 1 A g–1. The contribution here will guide future design of alloy-type anode materials toward advanced sodium-ion hybrid capacitors.

Atomically dispersed Mn atoms coordinated with N and O within an N-doped porous carbon framework for boosted oxygen reduction catalysis.

Developing efficient and robust catalysts to replace Pt group metals for the oxygen reduction reaction (ORR) is conducive to achieving highly efficient energy conversion. Here, we develop a general ion exchange strategy to construct highly efficient ORR catalysts consisting of various atomically dispersed metal atoms anchored on N-doped porous carbon (M-SAs/NC) to investigate the atomic structure-catalytic activity relationship. The structure characterization results demonstrated that the achieved atomic structure varied due to the presence of different metal centers. Mn-SAs/NC consists of MnN3O1 centers, in which the Mn single atoms are stabilized by 3 N and 1 O. In contrast, the center metals in Fe-/Co-/Cu single-atom catalysts are coordinated by merely N atoms. Mn-SAs/NC delivers superior performance for the ORR with a half-wave potential (E1/2) of 0.91 V vs. RHE in 0.1 M KOH solution, outperforming that of the commercial Pt/C catalyst and the control Fe-/Co-/Cu single-atom catalysts. Furthermore, Mn-SAs/NC also shows excellent methanol tolerance and stability up to 5000 cycles. Density functional theory (DFT) calculations reveal that Mn single atom catalysts with MnN3O1 centers contributed to the superior ORR performance with lower energy barriers and optimized adsorption capacity of intermediates. These findings provide insights into the design and development of specific coordinated structures of atomically dispersed catalysts to facilitate the practical applications of energy conversion.

N-bridged Ni and Mn single-atom pair sites: A highly efficient electrocatalyst for CO2 conversion to CO

Herein, we report highly efficient diatomic electrocatalysts with Ni and Mn single-atom pair sites decorated on N-doped porous carbon framework for CO2 conversion. The resulting catalysts can preferentially and rapidly convert CO2 into CO with a high Faradaic efficiency of 98.3% and an industrially relevant current density of – 300 mA cm−2 at a low overpotential of 0.287 V in a GDE-based flow reactor cell. Furthermore, it shows high cathodic energetic efficiencies over 80 % for CO production even under industrially relevant current densities. The in-depth experimental measurements and theoretical calculations reveal that the synergistic electronic modification effect caused by coupling neighboring Ni and Mn single atoms exhibits favorable characteristics in reaction steps of CO2 conversion such as CO2 adsorption/activation and immobilization of CO2 radical intermediate as well as adsorbed CO desorption, leading to highly efficient CO production.

In-situ synthesis of antimony nanoparticles encapsulated in nitrogen-doped porous carbon framework as high performance anode material for potassium-ion batteries

Antimony anodes for potassium-ion batteries (PIBs) have garnered considerable scholarly interest owing to their high theoretical specific capacity and low operation potential for alloying with potassium. However, the large volume expansion during alloying in Sb anodes results in rapid capacity fading. Thus, in this study, we proposed a simple, one-step, cost-effective carbothermal reduction method to synthesize a nanostructured Sb encapsulated in an N-doped porous carbon framework (Sb@NPC). The optimized Sb@NPC-2 electrode, which was obtained using a Sb2O3:polyvinylpyrrolidone (PVP) molar ratio of 1:3, offered a high reversible capacity of 587.7 mAh g−1 at 100 mA g−1 over 50 cycles, 492 mAh g−1 at 200 mA g−1 over 100 cycles, and 360.8 mAh g−1 at 800 mA g−1 with a capacity retention of 75.7% over 500 cycles. Even at a high specific current of 4000 mA g−1, the electrode maintained a high reversible capacity of 385 mAh g−1, implying adequate rate capability. In addition, a full cell composed of Sb@NPC-2 anode and KFe[Fe(CN)6⋅xH2O] cathode exhibited excellent cycling stability by showing an exceptional reversible capacity of 432.5 mAh g−1, corresponding to a high capacity retention of 98% over 150 cycles. These excellent results were primarily attributed to the successful encapsulation of nanostructured Sb nanoparticles in the NPC, as well as the formation of a KF-rich solid electrolyte interphase film on the electrode surface. Furthermore, the simulation result based on density functional theory (DFT) revealed that N-doping in the porous carbon framework enhanced the electrical conductivity and Sb−K binding.

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.

Reuse of Waste Road Asphalt:Fe/Fe3c Nanoparticles Encapsulated in N-Doped Porous Carbon Framework for Rechargeable Liquid and Flexible All-Solid-State Zinc-Air Batteries

Reuse of Waste Road Asphalt:Fe/Fe3c Nanoparticles Encapsulated in N-Doped Porous Carbon Framework for Rechargeable Liquid and Flexible All-Solid-State Zinc-Air Batteries

Bismuth Nanoparticle-Embedded Porous Carbon Frameworks as a High-Rate Chloride Storage Electrode for Water Desalination.

Capacitive deionization (CDI) is a promising cost-effective and low energy consumption technology for water desalination. However, most of the previous works focus on only one side of the CDI system, i.e., Na+ ion capture, while the other side that stores chloride ions, which is equally important, receives very little attention. This is attributed to the limited Cl- storage materials as well as their sluggish kinetics and poor stability. In this article, we demonstrate that a N-doped porous carbon framework is capable of suppressing the phase-transformation-induced performance decay of bismuth, affording an excellent Cl- storage and showing potential for water desalination. The obtained Bi-carbon composite (Bi/N-PC) shows a capacity of up to 410.4 mAh g-1 at 250 mA g-1 and a high rate performance. As a demonstration for water desalination, a superior desalination capacity of 113.4 mg g-1 is achieved at 100 mA g-1 with excellent durability. Impressively, the CDI system exhibits fast ion capturing with a desalination rate as high as 0.392 mg g-1 s-1, outperforming most of the recently reported Cl- capturing electrodes. This strategy is applicable to other Cl- storage materials for next-generation capacitive deionization.

A N-doped porous carbon framework with Ag-nanoparticles toward stable lithium metal anodes

A 3D porous carbon framework embedded with uniform Ag nanoparticles (ADPCF) is fabricated by a one-step chemical blowing process. The ADPCF electrode exhibits great cycling stability for over 2500 h (1250 cycles) with small hysteresis.

Synthesis of ultrafine Co/CoO nanoparticle-embedded N-doped carbon framework magnetic material and application for 4-nitrophenol catalytic reduction

An ultrafine Co/CoO nanoparticle-embedded N-doped porous carbon framework magnetic material was successfully synthesized based on a designed Co-MOF. Co/CoO@NC has good catalytic activity and recyclability for the 4-NP reduction reaction.

N-doped porous carbon wrapped FeSe2 nanoframework prepared by spray drying: A potential large-scale production technique for high-performance anode materials of sodium ion batteries

Transition metal selenides are promising anode materials for sodium ion batteries. However, large-scale production of these materials still challenges their practical applications. Herein, a facile and scalable strategy is developed to construct N-doped porous carbon framework wrapped FeSe2 composite (P–FeSe2/NCF) through an industrially established spray-drying process and salt-template method, which not only facilitates ion/electron transport, but also alleviates large volume variation. As anode material of sodium ion batteries (SIBs), P–FeSe2/NCF composite displays a reversible capacity of 507 mA h g−1 after 200 cycles at 2 A g−1 and 386.7 mA h g−1 at 10 A g−1 after 500 cycles. The galvanostatic intermittent titration technique (GITT) and electrochemical impedance spectroscopy (EIS) reveals that the remarkable performance of FeSe2/NCF composite is attributed to the homogeneous holes and conductive channels, which reduces sodium ion diffusion resistance and charge transfer resistance. This work demonstrates the successful preparation of FeSe2/NCF composite by using industrially established protocol, which sheds light on the massive production of high-performance anode materials of sodium ion batteries and their industrial application.

Energetic Metal-Organic Frameworks Derived Highly Nitrogen-Doped Porous Carbon for Superior Potassium Storage.

The carbonaceous materials with low cost and high safety have been considered as promising anodes for potassium-ion batteries (PIBs). However, it is still a challenge to design a carbonaceous material with long cycle life and high rate performance due to the poor K+ reaction kinetics. Herein, this article reports a N-doped porous carbon framework (NPCF) with a high nitrogen content of 13.57 at% within high doping level of the pyrrolic N and pyridinic N, which exhibits a high reversible capacity of 327mA h g-1 over 100 cycles at a current density of 100mA g-1 , excellent rate capability (144 and 105mA h g-1 at 10 and 20 A g-1 , respectively) and great cyclability of 258.9mA h g-1 after 2000 cycles at 1 A g-1 . Such a high rate performance and excellent cycling stability anode material is seldom reported in PIBs. Density functional theory (DFT) calculations reveal that the pyrrolic and pyridinic N-doping are helpful to enhance the K adsorption ability, thereby increasing the specific capacity.

RETRACTION: Carbon Quantum Dots Derived N-Doped Porous Carbon Frameworks with High Electrocatalytic for Oxygen Reduction Reaction

RETRACTION: Carbon Quantum Dots Derived N-Doped Porous Carbon Frameworks with High Electrocatalytic for Oxygen Reduction Reaction

Superhierarchical Conductive Framework Implanted with Nickel/Graphitic Carbon Nanocages as Sulfur/Lithium Metal Dual-Role Hosts for Li-S Batteries.

High-energy-density Li-S batteries (LSBs) are considered as a promising next-generation energy-storage system. However, the sluggish redox kinetics and severe polysulfide shuttle effect in elemental sulfur cathodes, along with uncontrollable dendrite propagation in lithium metal anodes, inevitably depress the electrochemical performance of LSBs and impede their practical implementation. Motivated by a unique hierarchical geometry, specific chemical affinity, and nitrogen-enriched collagen component of natural skin fibers (SFs), here we proposed an effective structural engineering strategy for crafting an SF-derived superhierarchical N-doped porous carbon framework in situ implanted with nickel/graphitic carbon nanocages as a dual-role host to simultaneously address the challenges faced on the sulfur cathode and lithium anode in LSBs. The experimental results and theoretical calculation disclose that the implanted Ni nanoparticles and highly graphitic sp2 carbon nanocages together with doped N heteroatoms not only provide a synergetic trapping-catalytic-conversion effect for regulating soluble polysulfides with promoted redox kinetics in the cathode at both room and elevated (55 °C) temperatures but also yield Ni-enhanced lithiophilic N-heteroatom active sites in the host framework to control Li deposition and suppress Li dendrite growth in anodes. Combining the cathodic and anodic improvements further achieves a superb rate and cycling performance in full LSB cells with stable Coulombic efficiency, showing great potential in developing reliable LSBs.

Space-confined synthesis of CoNi nanoalloy in N-doped porous carbon frameworks as efficient oxygen reduction catalyst for neutral and alkaline aluminum-air batteries

Exploring efficient and stable non-precious metal electrocatalysts for oxygen reduction reaction in neutral and alkaline solutions is of great importance for metal-air batteries. Herein, an efficient and stable electrocatalyst with CoNi nanoalloy (10–20 ​nm) uniformly embedded in porous N-doped carbon framework (CoNi-NCF) for neutral and alkaline primary Al-air batteries is prepared and studied. The CoNi-NCF electrocatalyst shows superior ORR performance in terms of half-wave potential of 0.91 ​V in 0.1 ​M KOH solution and 0.64 ​V in 3.5 ​wt% NaCl solution, outperforming those of the commercial Pt/C catalyst. Supported by in situ electrochemical Raman spectra and density functional theory calculations, the rich dual active sites of CoNi nanoalloy and porous N-doped carbon contributes to the outstanding ORR performance. Impressively, when employed as a cathode catalyst in both aqueous and solid flexible Al-air batteries, the CoNi-NCF-based Al-air batteries show the highest discharge performance, long-time durability and high flexibility, demonstrating the promising potential for practical application.

A novel popamine-imprinted chitosan/CuCo2O4@carbon/three-dimensional macroporous carbon integrated electrode

A novel Cu–Co-zeolite imidazole framework (Cu–Co-ZIF)-derived CuCo2O4@carbon nanocomposites supported on three-dimensional porous carbon (3D-KSC) were prepared to develop molecularly imprinted electrochemical sensors for sensing dopamine (DA). Firstly, polyhedral Cu–Co-ZIF was synthesized at room temperature and uniformly arrayed on 3D-KSC, and then the CuCo2O4@carbon nanostructure was obtained by high-temperature carbonization under nitrogen atmosphere. Finally, the molecularly imprinted polymer (MIPs) DA-imprinted chitosan was covered by potentiostatic electrodeposition to obtain the MIPs/CuCo2O4@carbon/3D-KSC integrated electrode. The results showed 15 μm-sized polyhedral Cu–Co-ZIF crystals were transformed into smaller irregular porous CuCo2O4@carbon nanocomposites with rough surface by calcination. Here, the produced 5 nm-sized CuCo2O4 crystals were uniformly embedded into the N-doped porous carbon frameworks. Various experimental conditions including the amount of Cu–Co-ZIF grew on 3D-KSC, calcination temperature, electrodepositing time of MIPs, the eluted time of template molecule and the pH of electrolyte were explored. The as-prepared MIPs/CuCo2O4@carbon/3D-KSC integrated electrode exhibited excellent anti-interference ability and good stability. The sensitivity for DA detection was 720.8 μA mM−1cm−2, the detection range was 0.51 μM–1.95 mM, and the detection limit was 0.16 μM.

Robust FeCo nanoparticles embedded in a N-doped porous carbon framework for high oxygen conversion catalytic activity in alkaline and acidic media

FeCo alloy nanoparticles were nucleated onto graphitic carbon layers through the pyrolysis of polydopamine (PDA) sub-micrometer spheres to form a highly active electrocatalytic system that exhibits excellent oxygen conversion catalytic activity in both alkaline and acidic media.