Nitrogen-doped Porous Carbon Materials Research Articles

Facile synthesis of nitrogen-doped porous carbon materials using waste biomass for energy storage applications

A simple, low-cost, and green route for the preparation of lotus carbon (LC) materials using lotus parts including leaves, flowers, fruits (seed pods), and stems as a renewable precursor is reported. Different porous carbons, leaf-carbon (LF-carbon), flower-carbon (FL-carbon), fruit-carbon (FR-carbon), and stem-carbon (ST-carbon) were synthesized from different parts of the lotus plant by simple carbonization method. The as-synthesized LC materials were well-characterized by many techniques such as electron microscopy and spectroscopy techniques, X-ray diffraction, and BET-surface area analysis. These techniques confirmed the porous structure of LC materials and the existence of heteroatoms in the prepared LC materials. The mesoporous structure of LC materials suggested employing it for the supercapacitor applications. The obtained FR-Carbon exhibits a high specific capacitance of 160 F/g in a three-electrode system in an aqueous 1 M H2SO4 electrolyte with a high rate performance of 52% retention from 0.5 to 5.0 A/g with good cycling stability of 95%. These results indicate that the porous carbon derived from lotus fruits is a potential electrode material for high-performance supercapacitors.

Preparation of Nitrogen-Doped Cellulose-Based Porous Carbon and Its Carbon Dioxide Adsorption Properties.

Nitrogen-doped cellulose-based porous carbon materials were obtained by hydrothermal method and KOH chemical activation together with melamine as a nitrogen-doping precursor. The effects of hydrothermal temperature on the microstructure and surface morphology of the products were mainly studied. Also, the carbon dioxide adsorption capacity of the prepared porous carbon was investigated. It was found that when the hydrothermal carbonization temperature was 270 °C and the mass ratio of cellulose and melamine was 1:1, the largest micropore specific surface area of 1703 m2·g–1 and micropore volume of 0.65 cm3·g–1 were obtained, with a nitrogen-doping composition of 1.68 atom %. At the temperature of 25 °C and under the pressure of 0.1, 0.2, 0.3, and 0.4 MPa, the adsorption amount of CO2 was 1.56, 3.79, 5.42, and 7.34 mmol·g–1, respectively. Also, the adsorption process of CO2 was in good accordance with the Freundlich isotherm model.

Nitrogen-Doped Porous Carbon Materials Derived from Graphene Oxide/Melamine Resin Composites for CO2 Adsorption.

CO2 adsorption in porous carbon materials has attracted great interests for alleviating emission of post-combustion CO2. In this work, a novel nitrogen-doped porous carbon material was fabricated by carbonizing the precursor of melamine-resorcinol-formaldehyde resin/graphene oxide (MR/GO) composites with KOH as the activation agent. Detailed characterization results revealed that the fabricated MR(0.25)/GO-500 porous carbon (0.25 represented the amount of GO added in wt.% and 500 denoted activation temperature in °C) had well-defined pore size distribution, high specific surface area (1264 m2·g−1) and high nitrogen content (6.92 wt.%), which was mainly composed of the pyridinic-N and pyrrolic-N species. Batch adsorption experiments demonstrated that the fabricated MR(0.25)/GO-500 porous carbon delivered excellent CO2 adsorption ability of 5.21 mmol·g−1 at 298.15 K and 500 kPa, and such porous carbon also exhibited fast adsorption kinetics, high selectivity of CO2/N2 and good recyclability. With the inherent microstructure features of high surface area and abundant N adsorption sites species, the MR/GO-derived porous carbon materials offer a potentially promising adsorbent for practical CO2 capture.

Synthesis of Nitrogen-Doped Hierarchical Porous Carbon Materials and its Catalytic Ability in Hydrogen Evolution Reaction

Hydrolysis for hydrogen production is one of the most efficient ways to produce hydrogen energy. In order to realize its wide application, people urgently need to find cheap and efficient metal-free electrocatalysts to replace the noble-metal electrocatalysts in hydrogen evolution reaction (HER). Here, N-doped hierarchical porous carbon materials were successfully fabricated without any template. We changed the nitrogen and carbon source needed to prepare the material and tested HER performance. In all samples, the ethylenediamine-based porous carbon material (NPC-2) compared with other nonmetallic heteroatom doped carbon materials and some traditional metallic catalysts exhibited outstanding HER performance and stability in acid solution. To achieve a 10 mA/cm2 HER current density, the nitrogen-doped hierarchical porous carbon materials (NPC-2) required an overpotential of 398 mV.

Porous carbon prepared by zeolitic imidazolate framework ( ZIF‐7‐III ) as the precursor for supercapacitor applications in different electrolytes

ZIF-7-III and its nitrogen-doped porous carbon (NPC) structures were synthesized for the first time by direct carbonization and fused with KOH in an argon atmosphere. The morphology and structural characterization of NPC materials were performed by scanning electron microscopy (SEM), Raman, Fourier transform infrared (FT-IR), and X-ray diffraction (XRD) analysis, and their supercapacitive properties were examined as a device form for the first time. The characteristic peak at 2θ = 9.1° in the XRD pattern indicates pure ZIF-7-III phase obtained, and impurity was not observed in the phase of ZIF-7-III. Two broad peaks at nearly 25° and 44° might belong to graphite and its diffractions for the NPC structures. The FT-IR analysis of ZIF-7-III and NPC materials matches well with the reported literature. Raman spectra of the activated NPC material show two prominent peaks located around 1357 and 1592 cm−1. A nonporous dense phase with a 2D stacked-layered structure was detected on the structure of ZIF-7-III. The morphology of activated NPC material turns into the 2D structure to the 3D dodecahedron morphology with an increase in the specific surface area. The cyclic voltammetry and galvanostatic cycling measurements of NPC structures were investigated on the device system in different electrolytes such as KOH, NaOH, LiOH, and Na2SO4. The electrochemical performance of NPC compounds was presented comparatively in a device, and the KOH-activated NPC material showed a higher specific surface area (709.7 m2/g) and higher capacitance value (104 Fg−1 at 0.4 Ag−1 and 118 Fg−1 for 5 mV/s) with low capacitive fade after 4000 charge/discharge cycles among others.

In-situ regeneration of tetracycline-saturated hierarchical porous carbon by peroxydisulfate oxidation process: Performance, mechanism and application

Carbonaceous material is not only the excellent adsorbent for organic contaminants removal, but also the effective activator for peroxydisulfate (PDS) activation. In this study, a nitrogen-doped hierarchical porous carbon material (NHGBC-800) presented the attractive bifunctional properties was developed for the removal of model organic contaminant antibiotic tetracycline (TC). On the one aspect, the NHGBC-800 had a large specific surface area (1178.0 m2/g) and achieved good TC removal with a maximal adsorption capacity (Qm) of 629.76 mg/g at 303 K. On the other aspect, TC-saturated NHGBC-800 could effectively activate PDS with itself as the activator, by which the mineralization of desorbed TC and in-situ regeneration of exhausted adsorbent were achieved simultaneously. The Qm of NHGBC-800 recovered 90.61% after first regeneration and still retained 77.18% even after the 6th adsorption-regeneration cycles. Moreover, the as-prepared material maintained good adsorption and regeneration performance under a wide range of pH conditions (3.02–9.83) and in the presence of inorganic anions such as Cl−, SO42−, NO3−, H2PO4−, HCO3−. The electro spin resonance (ESR), reactive oxygen species (ROS) quenching studies and electrochemical measurement revealed that the electron-transfer and single oxygen mediated the non-radical pathways dominated the TC degradation during the regeneration process. Compared with the conventional thermal and electrochemical regenerations, the in-situ regeneration of bifunctional carbon materials induced by PDS activation is more effective, sustainable and environmental-friendly.

Bimetal organic framework/graphene oxide derived magnetic porous composite catalyst for peroxymonosulfate activation in fast organic pollutant degradation

A magnetic nitrogen-doped porous carbon material (Co/CoOx@NC) with large surface area was synthesized for peroxymonosulfate (PMS) activation. The addition of reduced graphene oxide (rGO) remarkably improved the catalytic performance of Co/CoOx@NC due to its enhancement on graphitization degree and structural regulation. Co/CoOx@NC exhibited excellent PMS activation for phenol removal with almost 100% removal efficiency in 10 min, close to that of homogeneous Co2+. Simultaneously, good reusability and recyclability of Co/CoOx@NC was achieved, demonstrating its feasibility for practical application. The PMS activation process in Co/CoOx@NC/PMS system was dominant by efficient mediation of electron transfer from pollutants to PMS through the sp2-hybridized carbon and nitrogen network. Batch tests of various organic compounds removal revealed the specific selectivity related to the electron-donating ability in Co/CoOx@NC/PMS system. As the negligible role of reactive radicals on pollutants degradation, the inhibition of interfering species (e.g., Cl-, natural organic matters) was largely weakened. Present study not only provided a strategy for rationally designing highly efficient nanocarbon-based catalysts on PMS activation, but also presented new insight into the mechanism of PMS heterogeneous activation.

Nitrogen-doped hierarchical porous carbon nanomaterial from cellulose nanocrystals for voltammetric determination of ascorbic acid

The sensing application of cellulose nanocrystals (CNCs) is fascinating. CNCs can’t produce electrical or optical signals directly. Different from published sensing methods, a novel and simple electrochemical sensor for sensitive and selective detection of ascorbic acid (AA) was constructed based on three-dimensional nitrogen-doped hierarchical porous carbons (NHPC) by carbonizing CNCs and urea. Compared with bare glassy carbon electrode (GCE), the presence of porous carbons effectively increases the electron transport between analytes and the electrode, and significantly reduces the overpotential of AA oxidation. Under the optimum conditions, the electrode comprised of NHPC exhibits an extremely wide linear range from 8 × 10−5 to 1 × 10−2 M (R2 = 0.9996) and 1 × 10−6 to 5 × 10−5 M (R2 = 0.9867) to recognize the AA molecules, with a low detection limit of 2.45 × 10−7 M (S/N = 3) at a sensitivity of 0.1138 μA μM−1 cm−2. In particular, the sensing system for AA detection was further verified by the successful monitoring of AA in some spiked real samples. The fabricated nitrogen-doped CNC-based porous carbon material shows broad potential in the electrochemical application.

Preparation and electrochemical properties of MOF-derived nitrogen self-doped porous carbon

MOFs have various chemical components and structures, a high-specific surface area, potential redox sites and other significant advantages, which give them broad application prospects in the field of material synthesis as precursors. In this paper, MOF materials were synthesized by the solvent method, and MOF-derived nitrogen self-doped porous carbon materials were prepared by a one-step carbonization method. The effects of carbonization temperature and time on the structure and electrochemical properties of MOF-derived nitrogen self-doped porous carbon materials were investigated. The results show that MOF-derived nitrogen-doped porous carbon has an amorphous graphite carbon structure with a large specific surface area and various pore structures. In a 6 M KOH electrolyte solution, when the current density was 1 A g−1, the MOF-derived nitrogen-doped porous carbon material exhibited a specific capacitance of 219.4 F g−1; after 5000 cycles of constant current charging and discharging, the capacitance retention rate was still 88.94%, showing excellent electrochemical performance and good cycling stability.

Enhanced Fenton-like degradation of sulfadiazine by single atom iron materials fixed on nitrogen-doped porous carbon

The use of single-atom iron catalysts in heterogeneous Fenton-like reactions has demonstrated tremendous potential for antibiotic wastewater treatment. In this study, single-atom iron fixed on nitrogen-doped porous carbon materials (Fe-ISAs@CN) was synthesised using a metal organic framework (MOF) as a precursor. Fe-ISAs@CN was applied as a heterogeneous Fenton catalyst to activate H2O2 for the degradation of sulfadiazine (SDZ) in an aqueous solution. The physical and chemical properties of Fe-ISAs@CN were characterised by scanning electron microscopy (SEM), transmission electron microscope (TEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and rotating disk electrode (RDE) measurements. The results of our degradation experiments indicated that Fe-ISAs@CN exhibited remarkable activity and stability for the degradation of SDZ over a wide pH range; even after five cycles, Fe-ISAs@CN retained a high catalytic efficiency (>80%). The 5,5-dimethyl-1-oxaporphyrin-n-oxide (DMPO)-X signal captured by electron paramagnetic resonance (EPR) spectroscopy indicated that a large amount of hydroxyl radicals (OH) was produced in the reaction system. Quench tests indicated that the OH was the main active substance in the degradation of SDZ. The degradation products of the reaction were analysed by High Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS), and possible degradation pathways for the SDZ degradation were proposed.

Construction and preparation of nitrogen-doped porous carbon material based on waste biomass for lithium-ion batteries

Biomass derived carbon materials have been widely studied as electrodes in energy storage devices due to their renewable nature, low-cost and tunable physical/chemical properties. However, the influences of different treatments for biomass derived carbon materials are still lack of in-depth discussion. In this work, we investigate the effects of the treatment for biomass on the structure and composition of the resulted carbon materials. Especially, the optimal N-doped porous carbon (NPCCS), which was fabricated by H2SO4-assisted hydrothermal treatment and subsequent pyrolysis process using corn silk as raw material, shows a unique interconnected layered nanostructure with ultra-high nitrogen content (18.79 at%). As a result, the NPCCS electrode displays excellent cycling stability and outstanding rate performance in lithium-ion half-cell test and shows high first reversible specific capacity of 523.6 mAh g−1 in full-cell test. This work provides some guidance for preparing biomass derived carbon materials with superior electrochemical performance for the applications in advanced energy storage devices.

Comparison of the heteroatoms-doped biomass-derived carbon prepared by one-step nitrogen-containing activator for high performance supercapacitor

Heteroatoms-doped biomass-derived carbon materials (HBC), a new task and hotspot of the current energy research, especially supercapacitor, have featured with low cost and rich sources with enhanced physical, chemical and electrical properties compared with those of pure counterparts. Nevertheless, converting the biomass into high-performance carbon materials by green chemical activators and dopants is still imperatively needed. Herein, a simple and cost-effective one-step method was proposed, using different nitrogen-containing compounds (NH4Cl, (NH4)2CO3 and urea) as both activation agent and dopant, to prepare nitrogen-doped biomass-derived hierarchical porous carbon materials (HPCs). The effect of nitrogen-containing compounds on the electrochemical performance of HPCs was also studied. Among them, NH4Cl is proved to be the porogen with the minimum collapse of pollen grain and urea can be identified as the most effective N dopant. Furthermore, the prepared HPC-urea (HPC-U) electrode deliver the highest specific capacitance of 300 F g−1 at 1 A g−1 and rate performance of 50% from 1 to 50 A g−1 in three electrode system, while HPC-NH4Cl possesses the maximum capacitance retention rate of 95.2% after 10,000 cycles. In addition, HPC-U based SCs exhibits the highest energy density (14.3 Wh kg−1). Notably this work may provide a certain guideline for choosing N dopants and porogens to prepare biomass-derived carbon materials for the target application.

Chitosan gel synthesis nitrogen-doped porous carbon as electrode materials for supercapacitors

Herein, chemical activation of chitosan gel by KNO3 to prepare nitrogen-doped carbon. The sol-gel method enabled the activation agent KNO3 to be evenly dispersed in the carbon precursor, thereby getting a better activation effect, while the carbonized gel could produce more pores, resulting in a larger specific surface area of the material. Meanwhile, biomass chitosan was cheap and comes from a wide range of sources. The synthesized nitrogen-doped carbon (CUFK) material showed a unique graded pore structure, large specific surface area (678.8 m2 g−1) and N, O content (8.6%, 13.5%). Applied in the field of supercapacitors, it exhibited good capacitive performance (329.2 F g−1 in 6 M KOH electrolyte at 0.5 A g−1) and good cycle performance (only loss of 8.4% for 10000 cycles). These results show that the prepared nitrogen-doped porous carbon materials have good capacitive capacity, which provides a strategy for green production of carbon materials.

High-performance electrocatalyst based on polyazine derived mesoporous nitrogen-doped carbon for oxygen reduction reaction.

Nitrogen-doped porous carbon materials have high potential in metal-free electrocatalysts, which is essential for several renewable energy conversion systems. Herein, we report a convenient and environment-friendly method to fabricate a nitrogen doped mesoporous carbon (NMC) using a nonionic surfactant of Pluronic F127 micelles as the template and a Schiff-base polymer (polyazine) as the precursor. The synthesized NMCs were of spheric morphology and mesoporous structures with surface area up to 1174 m2 g−1 and high level of nitrogen (2.9–19 at%) and oxygen (4.9–7.4 at%) simultaneously doped. The electrochemical data of NMCs were analyzed in the context of the BET and XPS information. A correlation between ORR activity and the pyridinic-N was found. The NMC-700 demonstrate the highest electrocatalytic activity for ORR among the studied materials, which can be ascribed to the reasonable surface area and mesoporous structure, as well as the most abundant touchable pyridinic-N, thus providing more effective active sites for the oxygen reduction. In comparsion to the control sample, the NMC-700 provides the ORR electrocatalytic activity approximate to that of commercial Pt/C catalyst with a highly long-term stability.

One-step carbonization of a nickel-containing nitrogen-doped porous carbon material for electrochemical supercapacitors

Improving the graphitization degree of materials by Ni metal catalysis, so as to enhance the electrical properties of the material.

Boosting electrochemical performance of activated carbon by tuning effective pores and synergistic effects of active species

Clean energy conversion/storage techniques have become increasingly significant because of the increasing energy consumption. Regarding practical applications like zinc-air batteries and supercapacitors, electrode materials are essential and often require both porous networks and active species to enhance their electrochemical performance. Nitrogen-doped porous carbon (NPC) is a kind of promising material, which provides efficient active sites and large surface areas for energy conversion/storage applications. However, rational modulation of properties for maximizing NPC performance is still a challenge. Herein, a promising NPC material derived from natural biomass is successfully synthesized by following a stepwise preparation method. Physisorption and X-ray photoelectron spectroscopy (XPS) analyses demonstrate both pore structures and nitrogen species of the NPC have been delicately tuned. The optimized sample NPC-800-m exhibits excellent performance in both oxygen reduction reaction (ORR) and three-electrode supercapacitor measurement. Moreover, the homemade zinc-air battery and symmetric supercapacitor assembled with NPC-800-m also display outstanding energy and power density as well as durable stability. Density functional theory (DFT) calculations further confirm the synergistic effects among graphitic, pyridinic and pyrrolic nitrogen. The existence of multispecies of nitrogen combined with the optimized pore structure is the key to the high electrochemical performance for NPC-800-m. This work not only provides feasible and green synthetic methodology but also offers original insights into the effective pores and the synergistic effects of different nitrogen species in the NPC materials.

Porosity and composition of nitrogen-doped carbon materials templated by the thermolysis products of calcium tartrate and their performance in electrochemical capacitors

Porous nitrogen-doped carbon materials were synthesized by chemical vapor deposition method using template nanoparticles produced by the decomposition of calcium tartrate in thermal shock conditions. The synthesis temperature was varied from 650° to 900°C with a step of 50 °C and acetonitrile vapor was supplied into reactor immediately after the template formation. Transmission electron microscopy and X-ray diffraction analysis detected an increase of the number of ordered graphitic layers with the rise of the synthesis temperature. That was accompanied by a decrease of the specific surface area and the total pore volume determined from N2 adsorption measurements. Higher surface area of the materials produced at 650 and 700 °C was assigned to the co-existence of CaCO3 and CaO template nanoparticles at these temperatures. X-ray photoelectron spectroscopy found about 4–5 at% of nitrogen in all materials and a strong temperature-dependence of the ratio of nitrogen forms. The material synthesized at 750 °C showed the best electrochemical performance in 1 M H2SO4 electrolyte due to the presence of large fraction of pyridinic nitrogen responsible for pseudo-capacitance, graphitic nitrogen promoting charge transport, and large-size mesopores providing the fast diffusion of electrolyte ions.

Hydrothermal Activation of Porous Nitrogen-Doped Carbon Materials for Electrochemical Capacitors and Sodium-Ion Batteries.

Highly porous nitrogen-doped carbon nanomaterials have distinct advantages in energy storage and conversion technologies. In the present work, hydrothermal treatments in water or ammonia solution were used for modification of mesoporous nitrogen-doped graphitic carbon, synthesized by deposition of acetonitrile vapors on the pyrolysis products of calcium tartrate. Morphology, composition, and textural characteristics of the original and activated materials were studied by transmission electron microscopy, X-ray photoelectron spectroscopy, near-edge X-ray absorption fine structure spectroscopy, infrared spectroscopy, and nitrogen gas adsorption method. Both treatments resulted in a slight increase in specific surface area and volume of micropores and small mesopores due to the etching of carbon surface. Compared to the solely aqueous medium, activation with ammonia led to stronger destruction of the graphitic shells, the formation of larger micropores (1.4 nm vs. 0.6 nm), a higher concentration of carbonyl groups, and the addition of nitrogen-containing groups. The tests of nitrogen-doped carbon materials as electrodes in 1M H2SO4 electrolyte and sodium-ion batteries showed improvement of electrochemical performance after hydrothermal treatments especially when ammonia was used. The activation method developed in this work is hopeful to open up a new route of designing porous nitrogen-doped carbon materials for electrochemical applications.

Synthesis of nitrogen-doped porous carbon by solid grinding for supercapacitors

Nitrogen-doped porous carbon materials have been the outstanding candidates in supercapacitor applications due to their low cost, high surface area, abundant pore structure, suitable nitrogen doping content etc. Herein, nitrogen-doped porous carbon materials (NPC) were prepared via simple solid grinding using silica spheres as pore-forming agent and nitrogen-rich aniline as carbon/nitrogen precursor. The silica spheres create crossed macroporous structure that contributes to the transfer and storage of charge. NPC is continuously activated to give NPC-K, (where the K presents potassium hydroxide), further increasing its surface area and pore volume. The resulting NPC-K has hierarchical porous structures, high specific surface area, large pore volume, and suitable nitrogen doping. When used as an electrode material for supercapacitors, it has a good capacitance, rate performance, and cycle stability, demonstrating good electrochemical performance.

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.