Heteroatom-doped Porous Carbon Research Articles

Cellulose nanofiber enabled high-mass loading N-doped porous carbon electrode for zinc-ion supercapacitors

Zinc-ion hybrid supercapacitors (ZHSCs) are among the most promising electrochemical energy storage technologies because of their high energy density, environmental sustainability, low price, and inherent security. High-load, high-capacity cathodes are critical for the practical application of ZHSCs. However, it is challenging to achieve optimal performance of high-loading electrodes due to slow reaction kinetics, retarded ion transport, and structural instability. Herein, a salt-template technique was used to fabricate nitrogen-doped porous carbon (NPC) with large surface area, abundant mesopores, and electroactive nitrogen dopants. When combined with a fibrous network scaffold of carbon nanotubes and cellulose nanofibers (CNT/CNF), the optimized NPC delivered an outstanding specific capacitance of 133.4 mAh g−1 and a remarkable capacity retention of 95.4% after 10,000 cycles. More impressively, we achieved a cathode with high mass-loading of 10 mg cm−2 without significantly sacrificing the electrochemical performance (area capacity of 2.05 mAh cm−2 and good cycling stability with capacity retention of 86.2% after 3000 cycles). The excellent performance can be attributed to the continuous electron/ion conduction pathways of CNT/CNF scaffold and redox-active surface generated by the favorable heteroatom-doped porous carbon. In sum, this work offers a platform for making high mass-loading carbon electrodes for practical ZHSCs.

Preparation of natural N/O/S co-doped biomass-derived carbon materials for supercapacitors using multistage gas self-exfoliation effect

High-value utilization of biomass provided a feasible way to solve the energy shortage and environmental problems. The preparation of micro-mesoporous composite carbon materials from biomass waste as feedstock using a multistage gas self-exfoliation mechanism (CH3COOK and Ca2(C2H5COO)2) was a feasible approach. Among them, the N, O and S co-doped carbon materials were obtained in this paper by using forestry waste (bamboo) as raw material, spiral algae as green heteroatom dopant, Ca2(C2H5COO)2 as multifunctional template agent, and CH3COOK as gentle activator. The results indicated that BC-SA-0.5CP exhibited 324.85 F/g at 0.5 A/g. The symmetric supercapacitor (BSC-0.5//BSC-0.5) achieved 96.02% capacitance retention after 10,000 cycles, indicating excellent rate performance and charge/discharge stability. At a power density of 162.5 W/kg, the BSC-0.5//BSC-0.5 had an energy density of 14.67 Wh/kg. In addition, it was deeply analyzed the growth mechanism of heteroatoms, the formation mechanism of porous carbon and the electron transfer routes, which provided a theoretical basis for the preparation of biomass-derived carbon materials. Overall, this study demonstrated that the multistage gas self-exfoliation mechanism was beneficial in promoting the formation of micro-mesoporous composite structures and the growth of heteroatom functional groups, which ultimately provided a new route for the synthesis of natural heteroatom-doped porous carbon.

Heteroatoms-doped hierarchically porous graphene as electrode material for supercapacitors with ultra-high capacitance

In this work, a dual-templating pyrolysis strategy is successfully developed to synthesize a highly crumpled graphene (N-TRPG-800). The achievement of the graphene is based on the carbonization of the d(+)-glucosamine hydrochloride and the spatial confinement effect of the graphitic carbon nitride (g-C3N4) in the presence of zinc nanoparticles (Zn NPs). During the pyrolysis process, the d(+)-glucosamine hydrochloride first polymerizes into the layers of g-C3N4, which is derived from melamine. Afterwards, a further increase in pyrolysis temperature leads to the decomposition of g-C3N4 and the generation of reducing NH3 gas, which eventually resulting in the formation of 2D ultrathin structure and high heteroatoms doping degree. Simultaneously, the volatilization of the Zn NPs also plays a key role in the pore formation and the hierarchical structure generation. As a result, the as-synthesized graphene sheets simultaneously possesses hierarchical porous structure, high heteroatoms-doped degree, and large specific surface area (506 m2 g−1). Electrochemical measurements show that the N-TRPG-800 exhibits an ultrahigh supercapacitance of 471 F g−1 at 0.2 A g−1 in a three-electrode mode, approaching the theoretical capacitance of 550 F g−1 of graphene, which is superior to that of the state-of-the-art heteroatom-doped porous carbons in literature.

Nitrogen heteroatom anchored on porous carbon cathode for zinc ion hybrid capacitor

Heteroatom doped porous carbons have been widely used in aqueous zinc ion hybrid capacitors (AZICs) due to their merits of simple preparation process, excellent electric conductivity and abundant expose active sites. However, toxic and corrosive processes hinder their further applications. Herein, we report a template-free strategy to prepare nitrogen doped porous carbons from coal tar pitch for AZICs. Due to the structural characteristics of hierarchical pores and N, O heteroatoms, the AZIC fabricated by cathode presents the highest discharge capacity (133.1mAhg−1), the maximum energy density (112.3Wh kg−1), an excellent rate performance (65.9Wh kg−1at 15.26 kW kg−1) and a superior cycle stability over 15,000 cycles. This study points to an environmentally-friendly strategy to construct heteroatom-doped porous carbons for high-performance AZICs.

Pore-making strategy of bagasse-based heteroatom-doped porous carbon in chromium adsorbents

To enhance the utility of bagasse and increase its value, this study prepared bagasse-based activated carbon (ACUP) using a novel urea phosphate (UP) activator. The preparation involved a one-step activation and functionalization process under varying impregnation ratios and activation times. The resulting ACUP was characterized, and its specific surface areas and yields were compared between direct and two-step activation methods. The study also examined the impact of adsorption conditions on Cr(VI) removal performance. Findings revealed that the one-step method yielded activated carbon with high adsorption capacity (138.42 mg/g) and removal rate (79.45 %) for Cr(VI). The duration of activation time significantly influenced the adsorption capacity. These ACUP materials show great potential for practical Cr(VI) removal applications.

Renewable lignin-derived heteroatom-doped porous carbon nanosheets as an efficient oxygen reduction catalyst for rechargeable zinc-air batteries

Lignin upgrading to various functional products is promising to realize high-value utilization of low-cost and renewable biomass waste, but is still in its infancy. Herein, using industry waste lignosulfonate as the biomass-based carbon source and urea as the dopant, we constructed a heteroatom-doped porous carbon nanosheet structure by a simple NaCl template-assisted pyrolytic strategy. Through the synergistic effect of the NaCl template and urea, the optimized lignin-derived porous carbon catalyst with high content of active nitrogen species and large specific surface area can be obtained. As a result, the fabricated catalysts exhibited excellent electrocatalytic oxygen reduction activity, as well as good methanol tolerance and stability, comparable to that of commercial Pt/C. Moreover, rechargeable Zn-air batteries assembled with this electrocatalyst have a peak power density of up to 150 mW cm-2 and prominent long-term cycling stability. This study offers an inexpensive and efficient way for the massive production of highly active metal-free catalysts from the plentiful, inexpensive and environmentally friendly lignin, offering a good direction for biomass waste recycling and utilization.

Research Experiences via Integrating Simulations and Experiments (REVISE): A Model Collaborative Research Project for Undergraduate Students in CO2 Sorbent Design.

Undergraduate research experiences are an instrumental component of student development, increasing conceptual understanding, promoting inquiry-based learning, and guiding potential career aspirations. Moving one step further, as research continues to become more interdisciplinary, there exists potential to accelerate student growth by granting additional perspectives through collaborative research. This study demonstrates the utilization of a model collaborative research project, specifically investigating the development of sorbent technologies for efficient CO2 capture, which is an important research area for improving environmental sustainability. A model CO2 sorbent system of heteroatom-doped porous carbon is utilized to enable students to gain knowledge of adsorption processes, through combined experimental and computational investigations and learnings. A particular emphasis is placed on creating interdisciplinary learning experiences, exemplified by using density functional theory (DFT) to understand molecular interactions between doped carbon surfaces and CO2 molecules as well as explain underlying physical mechanisms that govern experimental results. The experimental observations about CO2 sorption performance of doped ordered mesoporous carbons (OMCs) can be correlated with simulation results, which can explain how the presence of heteroatom functional groups impact the ability of porous carbon to selectively adsorb CO2 molecules. Through an inquiry-focused approach, students were observed to couple interdisciplinary results to construct holistic explanations, while developing skills in independent research and scientific communications. This collaborative research project allows students to obtain a deeper understanding of sustainability challenges, cultivate confidence in independent research, prepare for future career paths, and most importantly, be exposed to strategies employing interdisciplinary research approaches to address scientific challenges.

Discarded Perseaamericana leaf-derived natural O, Mg, and Ca self-doped activated carbon and its applications as electrode materials for high-performance symmetric supercapacitors

Recently, there has been growing research interest in the fabrication of heteroatom-doped porous carbon from biomass. Herein, natural O, Mg, and Ca self-doped activated carbon was fabricated from discarded Persea americanaleaves via a one-step route strategy. By varying the carbonization temperature (500, 600, 700, and 800 °C), the as-fabricated DPAL-AC exhibits a high surface area (875.775 m2/g) and rich natural O, Mg, and Ca heteroatoms composition. The symmetric device product (DPAL-AC700) exhibits a high gravimetric capacitance of 209 F/gat 1 A/g. In addition, the device delivered an energy density of 28.4 Wh/kg at a power density of 135.5 W/kg. This work presents a novel approach to producing self-doped activated carbon with natural heteroatoms, which can enhance the performance of symmetric supercapacitors.

Solvothermal Synthesis and Pyrolysis Toward Heteroatom-Doped Carbon Microspheres for Zinc-Ion Hybrid Capacitors.

Heteroatom-doped porous carbon materials have investigated to promote the energy density of zinc-ion hybrid capacitors (ZICs). Yet, the quest for high-performance carbon materials or cathodes brings to light the question of which dopants facilitate fast energy storage kinetics and various types of pseudocapacitive reactions. Investigation of carbon materials with precise quantitative dopants as the key variable represents an effective appropriate approach to comprehending the intricate role of dopants in energy storage areas. Here, a straightforward solvothermal strategy is demonstrated for a variety of pristine and iron-incorporated polymer microspheres, used as precursors for durable spherical carbons intended for cathode applications in ZICs. The strategy effectively governs the incorporation of dopants within the carbon materials, whilewhile maintaining consistent morphology, microtexture, and pore structure across different carbon variations. The synergistic effect of various dopants enhance the pseudocapacitance and facilitate the ion storage process. In consequence, the optimal cathode delivers considerable capacity (178.8mAhg-1 at 0.5Ag-1), good energy density (120.2Whkg-1 at 336Wkg-1), and excellent cycling stability (101.5% capacity retention at 35000 cycles). The demonstration showcases a viable method for crafting carbon materials with precise dopants to accommodate the zinc anode, thus enabling high-capacity and high-energy ZICs.

Fabrication of solid-state high capacitance supercapacitor from N-doped biomass porous carbon

Heteroatom-doped porous carbon material fabricated from bio-resources has greatly attracted extensive interest in the energy storage field. In this work, we report the cheese-like porous carbon material enriching more heteroatoms such as oxygen and nitrogen fabricated from silkworm pupa in a facile carbonization and activation way. Benefited from the compromise between activator ratio and activation temperature in the activation process, the optimized sample of NBC600-1:3 presents not only a substantial surface of 2005.04 m2 g−1 but also a high heteroatom doped level of 11.90 %, leading to the achievement of the maximal mass specific capacitance of 406 F g−1 at 1 A g−1 and good rate capability up to 70.44 % (286 F g−1) at 20 A g−1 in 6 M KOH solutions. The symmetric electrochemical capacitor assembled displays a high energy density of 21.78 W h kg−1 (at 450 W kg−1) and a power density of 4500 W kg−1 (at 13.75 W h kg−1) in 1 M Na2SO4 solutions. Noticeably, the as-prepared quasi-solid device also presents a perspective performance in various bending angles, indicating a good flexible performance. This work provides the possibility for the application prospects of biomass carbon in flexible electronic.

Study on electrochemical supercapacitor performance of modified lavender biochar

In this study, we proposed a simple and low-cost method for the synthesis of heteroatom-doped porous carbons. Lavender waste residue as biomass precurso, using hydrothermal method synthesized N and S doped nano-layered porous carbon (NLPC-N/S) with high conductivity triumphantly. In the three-electrode system, NLPC-S showed an excellent capacitance (0.5A·g−1, 637.5 F·g−1) in 6 M KOH aqueous solution, which exceeded the specific capacitance of many reported biomass-derived porous carbons, and elucidated charge transfer mechanism and energy storage mechanism were both typical double-layer capacitance characteristics and pseudo-capacitance characteristics. The results of this study provide a cost-effective strategy for the recycling of biological waste, and that biomass carbon materials have high electrochemical performance potential in the field of energy storage.

Preparation of Biomass-Based Heteroatom-Doped Porous Carbon and Its Electrochemical Properties

Preparation of Biomass-Based Heteroatom-Doped Porous Carbon and Its Electrochemical Properties

Bidirectional pore-creating strategy towards lignin-based heteroatom-doped porous carbon for supercapacitors

Significant pursuits have been committed to manufacturing high-performance lignin carbon-based supercapacitor electrode materials due to their high carbon content, abundant raw resources, and environmentally-friendly. However, the pessimistic accessible porous structure and appetency to the electrolyte of electrode materials are two vital factors for restricting its performance. Here, a bidirectional pore-creating strategy is proposed to construct heteroatom-doped lignin-based porous carbon (HLPC) materials with a high electrochemical active area at supramolecular-level. In this process, activated-mediates with different pore-forming functions are assembled into lignin-based supramolecules by electrostatic forcing, and then hierarchical pore-creation and heteroatom doping are accomplished simultaneously in the pyrolysis process. The obtained carbon materials possess a tunable specific surface area of 543.4–1502.3 m2 g−1 and high heteroatom content of 9.4–16.2 at.%. Benefit from its admirable physicochemical properties, the HPLCs deliver a high ions appetency, ultrahigh capacitance of 380.5 F g−1 at 0.2 A g−1, and extremely long cyclic stability (100% after 10,000 cycles), which is superior 2.5-fold than that of YP-80F at the same mass loading. More promising, symmetrical electrode devices based on HLPCs possess a preeminent energy density of 30.0 Wh kg−1 in aqueous electrolyte. Overall, this protocol provides a new avenue for promoting the advancement of electrode materials in industrial-scale supercapacitors and manufacturing high-value-added products from plentiful bio-waste.

Phosphorus-induced formation of micropores and nitrogen groups for efficient CO2 capture: Experiments and DFT calculations

Due to their outstanding physicochemical characteristics, heteroatom-doped porous carbon materials have attracted significant attention. Herein, the pore structure and N content of the NPC-X material were regulated via P doping using a simple pyrolysis and activation method. The CO2 adsorption mechanism and electronic properties of the materials were determined by combining characterization results and theoretical calculations. Density functional theory calculations show that P has the capability to increase the porosity and facilitate the generation of pyridine-N and pyrrole-N functional groups in N-doped carbon materials. Moreover, the interaction between N groups and CO2 can be effectively elucidated through the analytical density of states. The experimental results show that the NPC-2 sample exhibits excellent CO2 adsorption performance (4.50 mmol/g at 298 K and 1 bar) and recycling stability. This study presents new synthetic approaches for the preparing N/P codoped carbon materials and explores the CO2 adsorption mechanism of materials with multiple coexisting functionalities.

Activation of peroxymonosulfate by tannin-derived porous carbon for enhanced bisphenol A degradation: Synergistic effect of surface nitrogen and oxygen functional groups

Heteroatom-doped porous carbon materials hold considerable potential in activating peroxymonosulfate (PMS) for environmental remediation. To fabricate highly efficient and cost-effective catalysts, renewable tannin was co-pyrolyzed with urea to achieve both efficient nitrogen doping and oxygen self-doping. The synergetic effect of N and O functional groups, combined with a well-developed porous structure, resulted in the development of N-enriched, O-functionalized porous carbon materials (NOPC) that exhibit exceptional catalytic activity in PMS activation for bisphenol A (BPA) degradation. As for the optimized NOPC-700/PMS system, the removal efficiency of BPA can reach up to 97.2% with a TOC removal efficiency of 78%. Control experiments, characterization results, and DFT calculations confirmed the prominent contribution of both the graphitic N and carbonyl group (CO) to the catalytic performance of NOPC. In addition, the applicability of NOPC was evaluated via varying influential factors, changing the targeted organic pollutant, and altering the water matrix. Furthermore, it was found that the main ROSs generated from PMS activation could be altered by incorporating N into the carbon catalysts. Overall, this work will provide a straightforward approach to designing highly efficient carbon catalysts with great potential in catalytic AOPs for wastewater treatment.

From weed to N/O/S co-doped honeycomb-like porous carbon for high-performance supercapacitors: a facile and friendly one-step carbonization

Recent research interest has increased in the production of heteroatoms-doped porous carbon with controlled morphology from biomass. However, there is still a significant challenge in resolving alkaline solutions that cause equipment corrosion and devising a simple and adaptable approach. In this study, N/O/S co-doped honeycomb-like porous carbons were synthesized from a widely cultivated annual weed (Hemistepta Iyrata Bunge) using a simple and eco-friendly method. The sodium hydroxide (NaOH)/urea system was utilized as the pore-forming agent and cellulose solvent, with urea as the nitrogen source. By varying the activation temperature, the as-prepared porous carbon has a high specific surface area (709 m2 g−1), a large total pore volume (0.44 cm3 g−1), and a high heteroatom content of 6.20 at% nitrogen and 8.12 at% oxygen. The prepared porous materials were evaluated as electrodes for supercapacitors. The product (HIB-PHC-750 °C) exhibited a high specific capacitance (353.6 F g−1 at 0.2 A g−1) at a carbonization temperature of 750 °C. Additionally, the HIB-PHC-750 °C-based symmetric device with a wide voltage range of 2.0 V possessed a desirable energy density of 44.22 Wh kg−1 at 500 W kg−1. Moreover, the HIB-PHC-750 °C also demonstrated outstanding cycling stability with 98.2 % capacitance retention after 10,000 cycles. This research provided a facile and favorable alternative method for preparing N/O/S co-doped honeycomb-like porous carbon for electrochemical energy storage devices.

Biomass waste derived heteroatom doping porous carbon sheets for high performance supercapacitor

Porous carbon sheets exhibit a big open flat layer with large surface area, short ion transfer distance, which has attracted massive research as electrode materials for supercapacitors. Here, O, N, and P co-doped porous carbon sheets (ONPC) were developed by one-step activation way using sunflower straw as the carbon source, NH4H2PO4 as phosphorus the source, and nitrogen source, and then activated by KHCO3. Benefiting from the suitable specific surface area and massive O (13.98 at%), N (7.43 at%), and P (0.81 at%) functional groups, the ONPC-700 electrode exhibits a specific capacitance of 340 F g−1 at 0.5 A g−1, superior electrochemical stabilization with the capacitance retention rate of 100.5% after 10,000 cycles. More interestingly, the assembled symmetric supercapacitor (ONPC-700//ONPC-700) achieves an energy density of 22.0 Wh Kg−1 and superior electrochemical stabilization. The above excellent results indicate that this paper offers a feasible and simple strategy for preparing biomass-based heteroatom doped porous carbon sheets for supercapacitors.

Microporous N- and O-Codoped Carbon Materials Derived from Benzoxazine for Supercapacitor Application

Heteroatom-doped porous carbon materials are highly desired for supercapacitors. Herein, we report the preparation of such material from polybenzoxazine (PBZ), a kind of phenolic resin. Four different N- and O-codoped microporous carbon materials were obtained by changing carbonization temperature (600, 700, 800, and 900 °C). Their structures were characterized by scanning electron microscopy (SEM), nitrogen isothermal absorption and desorption, X-ray diffraction (XRD), Raman spectroscopy, elemental analysis and X-ray photoelectron spectroscopy (XPS), and their electrochemical performances were evaluated by cyclovoltammetry (CV) and galvanostatic charge–discharge (GCD) test in a three-electrode system. It was found that the carbon material (C-700) prepared at the carbonization temperature of 700 °C possesses the largest specific surface area (SSA), total pore volume and average pore size among the family, and thus displays the highest specific capacitance with a value of 205 F g−1 at a current density of 0.25 A g−1 and good cycling stability. The work demonstrates that the N- and O-codoped microporous carbon materials with high electrochemical performance can be derived from benzoxazine polymers and are promising for supercapacitor application.

Microwave-assisted two-step pyrolysis of water hyacinth for the preparation of N-self-doped porous carbon

Biomass carbon, particularly heteroatom-doped porous carbon with additional pseudocapacitance, is widely used as an energy storage material. In this study, N-self-doped porous carbon enriched with hierarchical pore structures was prepared via microwave-assisted pyrolysis of water hyacinth. The porous carbon obtained at a heating power of 500 W and a final temperature of 700 °C (WPC-T7P5) has the highest specific surface area (SSA) of 2649 m2/g. In addition, WPC-T7P5 has abundant nitrogen-containing functional groups and a total N content of 2.73%. The carbon morphology and thermal stability show that the inorganic carbon content of WPC-T7P5 reaches 39.87% with a stable carbon structure. WPC-T7P5 possesses a specific capacitance of 374 F/g at 0.2 A/g and 254 F/g at 20 A/g, respectively, with a capacitance retention of 67.91%. A symmetrical supercapacitor based on WPC-T7P5 exhibits a maximum energy density of 8.09 Wh/kg at a power density of 50 W/kg. This study presents a novel microwave-assisted green technique to fabricate N-self-doped porous carbon.

Heteroatom-doped porous carbon derived from covalent organic framework for high performance supercapacitor applications

Heteroatom-doped porous carbon derived from covalent organic framework for high performance supercapacitor applications