Nitrogen-doped Porous Carbon Materials Research Articles

Sustainable supercapacitors of nitrogen-doping porous carbon based on cellulose nanocrystals and urea

The development of porous carbon materials from sustainable natural sources is an attractive topic in the field of energy storage materials. This study proposed the production of nitrogen-doped porous carbon (NPC) materials from the renewable cellulose nanocrystal (CNC) as carbon source and water-soluble urea as nitrogen source without any external activation. The liquid compounding treatment and subsequent carbonization provided the NPC materials a uniform and stable N-doping (7.4% nitrogen content), high specific surface area (366.5 m2/g) and various superior electrochemical properties. The fabricated NPC sample (CU-3, with the weight ratio of 1:10 for CNC and urea) exhibited a high specific capacitance of 570.6 F/g at a current density load of 1 A/g and good cycling stability (91.2% capacitance retention after 1000 cycles at a current density of 10 A/g) in the 6 M KOH electrolyte. Applying this NPC material as the electrode component in the assembled symmetric supercapacitor demonstrated the promising electrochemical stability with the specific capacitances of 88.2 F/g at the current density of 1 A/g and capacitance retention of 99.8% after 5000 cycles. The developed N-doped porous carbon material from CNCs and urea is expected to be a sustainable electrode component for the supercapacitor materials.

Sulfophilic and lithophilic sites in bimetal nickel-zinc carbide with fast conversion of polysulfides for high-rate Li-S battery

The notorious shuttle effect and slow reaction kinetics of lithium polysulfides (LiPSs) severely limit the cycle stability and rate performance of lithium sulfur (Li-S) batteries. Herein, we demonstrated that the issue of shuttling effect of LiPSs could be effectively addressed by using a separator coating based on Ni3ZnC0.7 bimetal carbide nanoparticles dispersed in nitrogen-doped porous carbon material matrix containing small amount of Ni metal particles, namely Ni3ZnC0.7/Ni/NCNTs. When used as a separator coating of Li-S cells, the Ni3ZnC0.7 bimetal carbides demonstrated efficient adsorption and catalytic effect towards LiPSs, inhibiting the shuttle effect and enhancing the electrochemical performance of device. The Li-S cell still maintained excellent charging and discharging platform even at a high rate of 7C. Theoretical calculation shows that, compared to the monometal carbide Ni3C, the bimetal carbide Ni3ZnC0.7 possesses the advantageous properties of both sulfophilic sites of Ni and lithophilic sites of Zn, resulting in reduced energy barriers for lithium ion diffusion and improved catalytic capability, thus enhancing reaction kinetics of LiPSs. This work paves a new way to resolving the critical issues of shuttle effect, cycle stability and rate capability of Li-S batteries by taking advantage of synergistic effect of Ni and Zn in the bimetal carbide.

High-Voltage and Ultrastable Aqueous Zinc–Iodine Battery Enabled by N-Doped Carbon Materials: Revealing the Contributions of Nitrogen Configurations

The rechargeable aqueous zinc–iodine (Zn–I₂) battery has emerged as a promising electrochemical energy storage technology. However, poor cycling stability caused by the dissolution of iodine species into the electrolyte limited its practical application. Herein, we report a nitrogen-doped porous carbon (NPC) material in gram scales. Performed as an iodine host in the Zn–I₂ battery, the NPC shows a high specific capacity (345.3 mAh g–¹ at 0.2 C), superior rate capability (53.2% capacity retention at 10 C), and remarkable cycling stability (10 000 cycles at 10 C with a capacity retention of 80.9%). More importantly, DFT computations reveal that the graphitic-N (N-Q) exhibits the strongest adsorption of iodine; however, pyridinic-N (N-6) shows the weakest adsorption of iodine. Moreover, the N-6/N-Q ratio is an essential parameter that significantly determined the electrochemical performance of Zn–I₂ batteries. Therefore, the improved long-term cycling stability and rate capability of the as-designed Zn–I₂ battery are attributable to the decrease of the N-6/N-Q ratio. This work is of great significance for devolving highly reversible Zn–I₂ batteries.

Biomass-derived nitrogen-doped porous carbons with ultra-high surface area for electrocatalytic oxygen reduction reaction

Highly efficient and stable metal-free Oxygen Reduction Reaction (ORR) catalyst is derived from low-cost and green biomass, the plum blossom. After activating with KOH and doping with N via introduction of melamine followed by high-temperature treatment, the obtained porous carbon exhibits unique honeycomb like structure and ultra-high surface area of up to 2118.9 m 2 g −1 together with multiple N coordination in carbon matrix. These characteristics endow the as-prepared electrocatalysts with high catalytic activity ( E 1/2 = 0.82 V and J L = 5.96 mA cm −2 ) as well as outstanding long-term stability (current retention of 91.2% after 50,000 s) and methanol tolerance in alkaline media. Consequently, it is of immense significance to fabricate novel ORR catalysts derived from biomass in the evolvement of fuel cells. A nitrogen-doped porous carbon material was prepared from fallen plum blossom by chemical activation and post-treatment. Applied in the field of electrochemistry, the catalyst showed good oxygen reduction reaction performance. • The carbon-based metal-free electrocatalysts were derived from natural plum blossoms. • The PBC-A catalysts with homogeneous micro/ meso /macroporous structure and extremely large surface area were synthesized. • The PBC-A catalysts possesses high ORR performance in alkaline solution. • The PBC-A catalysts realizes a good long-time stability (current retention of 91.2% after 50,000 s) and methanol tolerance.

Porous nitrogen doped carbon materials as High-Active Oxygen Reduction Catalysts Derived from Biomass (Corn Stalk)

Porous nitrogen doped carbon materials as High-Active Oxygen Reduction Catalysts Derived from Biomass (Corn Stalk)

Nitrogen-doped porous carbon composite with three-dimensional conducting network for high rate supercapacitors

Nitrogen-doped porous carbon materials are widely used as electrode materials for supercapacitors. However, the electrodes based on these materials generally suffer from poor conductivity due to point-to-point contact of granular materials, especially at high charging/discharging rates. Herein, nitrogen-doped porous carbon composite (N-PC/CNT) with three-dimensional (3D) conducting network is prepared by carbonizing carbon nanotube (CNT) thread zeolitic imidazolate framework-8 (ZIF-8) composite. In this construction, the carbonized ZIF-8 with rich pore structure serves as a “reservoir” to provide storage space for electrolyte ions, while CNTs act as “wires” to form internal 3D conducting network for rapid electron transfer. As a result, the obtained N-PC/CNT exhibits a high specific capacitance of 334.5 F g−1 at 1 A g−1, excellent rate capability (195.5 F g−1 at 100 A g−1, capacitance retention of 58%), remarkable cycling stability (almost 100% capacitance retention after 20000 cycles) and outstanding frequency response with an ultrahigh rate up to 3 V s−1 in 6 M KOH electrolyte. These prominent performances result from the synergy of high nitrogen doping content (12.1 at.%), large specific surface area (980.2 m2 g−1), suitable pore size distribution and excellent conductivity. The assembled N-PC/CNT//N-PC/CNT symmetric supercapacitor exhibits a maximal energy density of 17 Wh kg−1 at a power density of 533 W kg−1 in 1 M Na2SO4 electrolyte. Evidently, the nitrogen-doped porous carbon composite has a great development potential for advanced supercapacitors or other electrochemical energy storage devices.

Biomass Juncus Derived Nitrogen-Doped Porous Carbon Materials for Supercapacitor and Oxygen Reduction Reaction.

Juncus is a perennial herb aquatic plant found worldwide, with high reproductive ability in warm regions. It has three-dimensional hierarchical porous triangular networks structures composited of tubular fibers. Here, juncus derived nitrogen-doped porous carbon (NDPC) was prepared by mixing juncus and ZnCl2 through one-step pyrolysis and activation which is a low-cost, simple, and environmentally friendly method. The NDPC had hierarchical porous structures and a high specific surface area and was applied for supercapacitor and oxygen reduction reaction (ORR). The resulted NDPC-3-800 was prepared by mixing juncus with ZnCl2 at a mass ratio of 1:3 and then carbonized at 800°C, it was used as electrode material of a supercapacitor. The supercapacitor exhibited excellent specific capacitance of 290.5 F g−1 and 175.0 F g−1 in alkaline electrolyte at the current densities of 0.5 A g−1 and 50 A g−1, respectively. The supercapacitor showed good cycle stability, and the capacitance was maintained at 94.5% after 10,000 cycles. The NDPC-5-800 was prepared by mixing juncus with ZnCl2 at a mass ratio of 1:5 and then carbonized at 800°C. It exhibited outstanding ORR catalytic activity and stability attributing to their high specific surface area and abundant actives sites. The juncus can derive various materials for application in different fields.

Electrochemical performance of polyacrylamide hydrogel based nitrogen-doped porous carbon for supercapacitor

Nitrogen-doped porous carbon materials for supercapacitor was successfully fabricated from precursor of polyacrylamide gel through freeze drying, carbonization and KOH activation process. The precursor of polyacrylamide gel was prepared using acrylamide and N,N-methylene diacrylamide as monomers and cross-linking agents, respectively. The nitrogen-doped porous carbon was tested by field emission scanning electron microscope, transmission electron microscope, Fourier transform infrared spectroscopy, Raman spectrum, X-ray electron spectrum and specific surface analysis, respectively. Further, the electrochemical performance of nitrogen-doped porous carbon was tested by using a three-electrode system, which exhibited large specific capacitance of 302.1 F/g at 1 A/g, good rate property (71.8%, 217 F/g at 20 A/g) and cycle property (96% after 8000 cycles). Symmetrical supercapacitor was also assembled with an extended operating voltage window of 1.8 V in 1 M Na2SO4 electrolyte. More significantly, the nitrogen-doped porous carbon maintains an energy density of 23.27 Wh/kg in the case of a power density of 450 W/kg.

Template-Free Synthesis of N-Doped Porous Carbon Materials From Furfuryl Amine-Based Protic Salts.

Nitrogen-doped porous carbon materials (NPCMs) are usually obtained by carbonization of complicated nitrogen-containing polymers in the presence of template or physical/chemical activation of the as-synthesized carbon materials. Herein we reported the facile synthesis of NPCMs by direct carbonization of a series of furfuryl amine (FA)-based protic salts ([FA][X], X = NTf2, HSO4, H2PO4, CF3SO3, BF4, NO3, Cl) without any templates, tedious synthetic steps and other advanced techniques. The thermal decomposition of precursors and structure, elemental composition, surface atomic configuration, and porosity of carbons have been carefully investigated by thermogravimetric analysis (TGA), X-ray diffraction (XRD), Raman spectra, X-ray photoelectron spectroscopy (XPS), combustion elemental analysis, energy-dispersive spectrometry, and nitrogen isotherm adsorption. Different from the parent amine FA that was evaporated below 130°C and no carbon was finally obtained, it was found that all the prepared protic precursors yield NPCMs. These carbon materials were found to exhibit anion structure- dependent carbon yield, chemical composition, and porous structure. The obtained NPCMs can be further exploited as adsorbents for dye removal and decoloration. Among all NPCMs, [FA][H2PO4]-derived carbon owing to its high surface area and special pore structure exhibits the highest adsorption capacities toward both Methylene blue and Rhodamine B.

Deep insight into the pore size distribution of N-doped porous carbon materials on electrochemical energy storage and CO2 sorption

Nitrogen-doped porous carbon materials with controllable pore sizes are selectively prepared via carbonization of banana sheets combined with KOH activation. The resulting carbon materials, featured with a well-designed pore size distribution, high specific surface area, exhibits excellent capacitive performance in aqueous electrolyte (264 F/g at 1 A/g). More importantly, the symmetric supercapacitor exhibited a maximum specific capacitance of 155 F/g and a corresponding energy density of 48.44 Wh/kg at a current density of 1 A/g in organic electrolyte. Further investigation revealed that the enhanced supercapacitance is attributed to the pore size (especially in the range of 0.9–1.2 nm) and N-doped. The prepared carbon also displays an excellent CO2 adsorption ability due to the suitable pore size distribution as high as 5.29 mmol/g and 4.16 mmol/g at 0 °C and 25 °C under 1 bar, respectively. The present investigation will provide a new avenue for the wide application of biomass-derived porous carbon in various fields.

Nitrogen-doped porous carbon materials derived from ionic liquids as electrode for supercapacitor

Nitrogen-doped porous carbon materials (NPCs) were successfully obtained through one-step carbonization of an ionic liquid, that is, 1-ethyl-3-methylimidazolium dicyanamide (EMIM-dca), adopting eutectic salt (ZnCl2-NaCl) as the porogen agent. The nitrogen content and textural structure of the obtained carbon materials are highly dependent on the dosage of salt. The as-prepared NPCs integrate the superiorities of reasonable pore structure, high nitrogen content as well as homogeneous distribution, and high surface area. When served as electrodes for supercapacitor, a typical NPC-2 electrode exhibits a high specific capacitance of 335.3 and 206 F g−1 at current densities of 0.5 and 10 A g−1, respectively, considerable energy density (up to 10.1 Wh kg−1), and excellent cycling stability with almost no degradation over 10,000 cycles in KOH aqueous solution.

Ionic electro-active polymer actuator based on cobalt-containing nitrogen-doped carbon/conducting polymer soft electrode

Nanoscale cobalt-containing nitrogen-doped porous carbon (CoNC) materials were prepared by thermolysis of a zeolitic imidazolate framework (ZIF), ZIF-67, at different temperatures and their application for ionic electro-active polymer (EAP) actuator was evaluated. CoNC-700, which was obtained from ZIF-67 pyrolysis at 700 °C, exhibits specific surface area of 753.86 m2 g−1, pore volume of 0.5768 cm3 g−1, and specific capacitance of 120.7 F∙g−1. CoNC/conducting polymer soft electrode were fabricated by unitizing effective interaction of CoNC with poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). High-performance ionic actuators were developed for the first time using this CoNC/PEDOT:PSS soft electrode. The developed ionic EAP actuator exhibited large peak-to-peak displacement of 20.4 mm and high bending strain of 0.28% (3 V and 0.1 Hz). Therefore, ZIFs or metal organic frameworks (MOFs) can be applied to provide significant improvements in EAP actuators, which can play key roles as technological advances toward bioinspired actuating devices required for next-generation soft and wearable electronics.

Preparation of nitrogen-doped hierarchical porous carbon materials by a template-free method and application to CO2 capture

The excessive emission of greenhouse gases such as carbon dioxide (CO2) increases the average surface temperature of the earth through the greenhouse effect. Nitrogen-doped porous carbon materials are considered to be promising solid adsorbents for CO2 capture. Herein we report a synthesis of nitrogen-doped porous carbon materials using a template-free method. The effects of different nitrogen sources and different carbon sources on the CO2 adsorption performance of porous carbon materials were studied.The result indicated the ethylenediamine based porous carbon material showed the highest micropore volume and the most surface basic nitrogen atoms, and both lead to good CO2 adsorption performance. Moreover, it was found that the sample maintained thermal and chemical stability in a long-term (ten cycles) CO2 adsorption/desorption experiment.

Nitrogen-doped hierarchically structured porous carbon as a bifunctional electrode material for oxygen reduction and supercapacitor

Development of an efficient electrode material with robust porous architecture, high catalytic activity and excellent electrochemical performance toward both oxygen reduction reaction (ORR) and supercapacitor is extremely important. Herein, a facile route to fabricate nitrogen-doped hierarchical porous carbon (NHPC) materials as a bifunctional electrode material for ORR and supercapacitors is presented. The as-prepared NHPC-0.5 integrate the feature of high-level nitrogen-doping (12.1 at %), large specific surface area (up to 1798.4 m2 g−1) and hierarchical multi-pores of cross-linked micro and mesoporous channels. When used as ORR electrocatalyst, the NHPC-0.5 demonstrated highest selectivity (four-electron transfer process), high activity (half-wave potential 0.883 V vs. RHE, initial potential 1.004 V vs. RHE) and favorable tolerance against methanol. When tested its application in zinc-air batteries, its maximum output power density was 25.1 mW cm−2, and delivers a superior durability of negligible potential loss after 100 cycles. When applied in supercapacitor, the NHPC-0.5 can deliver a high specific capacitance of 283.7 F g−1 at current density of 1 A g−1 in 1 M H2SO4 electrolyte, and outstanding cyclic stability (105.8% capacitance retention after 40,000 cycles). Moreover, a symmetric supercapacitor (NHPC-0.5//NHPC-0.5) can release an energy density of 11.3 W h kg−1 at the power density of 502 W kg−1. The encouraging results of this work may provide a new perspective to construct N-doped hierarchical porous carbon materials in energy storage devices with excellent electrochemical performance.

Revealing of Active Sites and Catalytic Mechanism in N-Coordinated Fe, Ni Dual-Doped Carbon with Superior Acidic Oxygen Reduction than Single-Atom Catalyst.

Herein, we synthesized a Fe, Ni dual-metal embedded in porous nitrogen-doped carbon material to endow higher turnover frequency (TOF), lower H2O2 yield, and thus superior durability than for the single-atom catalyst for oxygen reduction in acid media. Quantitative X-ray absorption near edge structure (XANES) fitting and density functional theory (DFT) calculation were implemented to explore the active sites in the catalysts. The results suggest FeNi-N6 with type I (each metal atom coordinated with four nitrogen atoms) instead of type II configuration (each metal atom coordinated with three nitrogen atoms) dominates the catalytic activity of the noble-metal free catalyst (NMFC). Further, theoretical calculation reveals that the oxygen reduction reaction (ORR) activity trend of different moieties was FeNi-N6 (type I) > FeNi-N6 (type II) > Fe-N4 > Fe2-N6. Our research represents an important step for developing dual-metal doping NMFC for proton exchange membrane fuel cells (PEMFCs) by revealing its new structural configuration and correlation with catalytic activity.

Ionic liquids self-templating to synthesize nitrogen-doped porous carbon materials for CO2 adsorption

Ionic liquids self-templating to synthesize nitrogen-doped porous carbon materials for CO2 adsorption

Diphenylmethane-based cross-linked polyisocyanide: synthesis and application as nitrite electrochemical probe and N-doped carbon precursor

With 4,4′-diaminodiphenylmethane as the starting material, a compound (M1) containing two functional isocyanide groups was successfully prepared via Hofmann method, and a polyisocyanide derivative (P1), with a cross-linked structure, was successfully prepared via Ni2+-catalyzed polymerization. Electrochemical detection of nitrite was achieved by utilizing P1-modified glassy carbon electrode as the working electrode, and the corresponding detection limit reached ~ 0.51 μM (3σ/k). Subsequently, nitrogen-doped porous carbon material (P1-C) was obtained by direct carbonization of P1. The preliminary study of its electrochemical performance was carried out. Specific capacitance of P1-C reached 152.5 F g−1 at 0.5 A g−1, and high capacitance retention of 94.4% was recorded after 1000 galvanostatic charge–discharge cycles (at 1 A g−1), indicating that P1-C can act as potential energy storage electrode material.

Houttuynia-derived nitrogen-doped hierarchically porous carbon for high-performance supercapacitor

Three-dimensional (3D) heteroatom-doped nanostructured carbon materials have gained extensive attention because of their tremendous potential for enhancing supercapacitor performance. Herein, based on a mild carbonization/activation process we successfully developed green/sustainable 3D hierarchically porous nitrogen-doped nanostructure carbon (N–HNC) materials from houttuynia biomass, showing high specific capacitance and high cyclic stability. The as-prepared houttuynia-derived porous carbon material shows a unique flower-like architecture with well-distributed micro/meso pores and a high specific surface area of 2090 m2/g. The assembled supercapacitor based on N–HNC sample shows superior specific capacitance (473.5 F/g at 1 A/g) and remains over 50% of specific capacitance at 20 A/g. The N–HNC based symmetric supercapacitor, constructed with a two-electrode configuration, shows an energy density of 15.99 Wh/kg at 500 W/kg and outstanding capacitance retention of 95.74% even after 10,000 charge-discharge cycles at 10 A/g in an aqueous 6 M KOH electrolyte system. The results highlight the potential of the 3D porous N-doped hierarchical nano-structural carbon materials from houttuynia biomass as candidate electrodes for supercapacitor applications. This study provides an example of using the inherent framework structure of biomass as a precursor to synthesize hierarchically porous nitrogen-doped nanostructure for high-performance supercapacitor applications.

Carbonization and Preparation of Nitrogen-Doped Porous Carbon Materials from Zn-MOF and Its Applications.

Nitrogen-doped porous carbon (NPC) materials were successfully synthesized via a Zn-containing metal-organic framework (Zn-MOF). The resulting NPC materials are characterized using various physicochemical techniques which indicated that the NPC materials obtained at different carbonization temperatures exhibited different properties. Pristine MOF morphology and pore size are retained after carbonization at particular temperatures (600 °C-NPC600 and 800 °C-NPC800). NPC800 material shows an excellent surface area 1192 m2/g, total pore volume 0.92 cm3/g and displays a higher CO2 uptake 4.71 mmol/g at 273 k and 1 bar. Furthermore, NPC600 material displays good electrochemical sensing towards H2O2. Under optimized conditions, our sensor exhibited a wide linearity range between 100 µM and 10 mM with a detection limit of 27.5 µM.

Nitrogen-Doped Porous Carbon Material Derived from Biomass of Beancurd as an Efficient Electrocatalyst for Oxygen Reduction and Zn-air Fuel Cell

Developing efficient and affordable electrocatalysts for oxygen reduction reaction (ORR) is very important for next-generation energy conversion and storage devices. Herein, N-doped carbon materials with high N-doping level (5.02 at%) and hierarchically porous structure (H-NHPC) were fabricated by pyrolysis of inexpensive beancurd soaked with urea and NaCl, which was employed as an extra nitrogen resource and a green template to control the morphology and porosity, respectively. The as-prepared H-NHPC exhibited better ORR catalytic activity than the benchmark Pt/C electrocatalysts and most of other biomass-driven nitrogen-doped carbon materials in alkaline medium. The excellent catalytic activity of H-NHPC was attributed to its high content of catalytic active species such as pyridinic-N and graphitic-N, large surface area (988.2 m2 g−1) and abundant porosity ranging from micro- to meso- and macro-scale for efficient mass transfer. Furthermore, the Zn-air battery (ZAB) assembled with H-NHPC as the air electrode displayed higher power-density, larger specific-capacity and better rate-capability than the Pt/C-based ZAB, showing great application perspective in metal-air batteries.