As-prepared Carbon Research Articles

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.

Covalent triazine polymer derived porous carbon with high porosity and nitrogen content for bifunctional oxygen catalysis in zinc–air battery

Nitrogen-doped porous carbon possesses widespread applications in energy-related fields due to its unique properties. However, preparation of porous carbon (specific surface area > 3000 m2 g–1) with high nitrogen content (> 10 wt%) remains great challenges because of high synthesis temperature. Herein, a covalent triazine polymer was innovatively designed by cyclotrimerization of tetracyanoethylene, and used to produce the high nitrogen-doped porous carbon. The as-prepared porous carbon (HNPC-900) possesses a high nitrogen content (14.2 wt%) and large specific surface area (3210 m2 g–1). When HNPC-900 was applied as the air-cathode for zinc–air batteries, it shows a high specific capacity (797 mAh gzn–1) and stable rechargeability (more than 380 h over 960 cycles at 5 mA cm–2), outperforming the cathode composed of RuO2 and 20 wt% Pt/C. This ingenious design provides a feasible strategy to prepare high nitrogen-doped porous carbon, giving extensive application prospects of porous carbon for catalysis and energy storage fields.

Biomass Based N/O Codoped Porous Carbons with Abundant Ultramicropores for Highly Selective CO2 Adsorption

In this work, N/O codoped porous carbons (NOPCs) were derived from corn silk accompanied by Na2CO3 activation. The porous structures and surface chemical features of as-prepared carbon materials were tailored by adjusting the Na2CO3 mass ratio. After activation, the optimized sample (NOPC1) with abundant ultramicropores and pyrrolic N displays an enhanced CO2 adsorption capacity of 3.15 mmol g−1 and 1.95 mmol g−1 at 273 K and 298 K at 1 bar, respectively. Moreover, this sample also exhibited high IAST selectivity (16.9) and Henry’s law selectivity (15.6) for CO2/N2 at 298 K as well as moderate heat adsorption. Significantly, the joint effect between ultramicropore structure and pyrrolic N content was found to govern the CO2 adsorption performance of NOPCs samples.

In-situ formation of nitrogen doped microporous carbon nanospheres derived from polystyrene as lubricant additives for anti-wear and friction reduction

This study presents a nitrogen-doped microporous carbon nanospheres (N@MCNs) prepared by a facile polymerization–carbonization process using low-cost styrene. The N element in situ introduces polystyrene (PS) nanospheres via emulsion polymerization of styrene with cyanuric chloride as crosslinking agent, and then carbonization obtains N@MCNs. The as-prepared carbon nanospheres possess the complete spherical structure and adjustable nitrogen amount by controlling the relative proportion of tetrachloromethane and cyanuric chloride. The friction performance of N@MCNs as lubricating oil additives was surveyed utilizing the friction experiment of ball-disc structure. The results showed that N@MCNs exhibit superb reduction performance of friction and wear. When the addition of N@MCNs was 0.06 wt%, the friction coefficient of PAO-10 decreased from 0.188 to 0.105, and the wear volume reduced by 94.4%. The width and depth of wear marks of N@MCNs decreased by 49.2% and 94.5%, respectively. The carrying capacity of load was rocketed from 100 to 400 N concurrently. Through the analysis of the lubrication mechanism, the result manifested that the prepared N@MCNs enter clearance of the friction pair, transform the sliding friction into the mixed friction of sliding and rolling, and repair the contact surface through the repair effect. Furthermore, the tribochemical reaction between nanoparticles and friction pairs forms a protective film containing nitride and metal oxides, which can avert direct contact with the matrix and improve the tribological properties. This experiment showed that nitrogen-doped polystyrene-based carbon nanospheres prepared by in-situ doping are the promising materials for wear resistance and reducing friction. This preparing method can be ulteriorly expanded to multi-element co-permeable materials. Nitrogen and boron co-doped carbon nanospheres (B,N@MCNs) were prepared by mixed carbonization of N-enriched PS and boric acid, and exhibited high load carrying capacity and good tribological properties.

Multifaceted Carbon Dots: toward pH-Responsive Delivery of 5-Fluorouracil for In Vitro Antiproliferative Activity.

The synthesis of smart hybrid material to assimilate diagnosis and treatment is crucial in nanomedicine. Herein, we present a simple and facile method to synthesize multitalented blue-emissive nitrogen-doped carbon dots N@PEGCDs. The as-prepared carbon dots N@PEGCDs show enhanced biocompatibility, small size, high fluorescence, and high quantum yield. The N@PEGCDs are used as a drug carrier for 5-fluorouracil (5-FU) with more release at acidic pH. Furthermore, the mode of action of drug-loaded CD (5FU-N@PEGCDs) has also been explored by performing wound healing assay, DCFDA assay for ROS generation, and Hoechst staining. The drug loaded with carbon dots showed less toxicity to normal cells compared to cancer cells, making it a perfect candidate to be studied for designing next-generation drug delivery systems.

Biomass derived N/O self-doped porous carbon for advanced supercapacitor electrodes

To satisfy the practical needs of the sustainability and industrialization of supercapacitors, it is essential to maintain good electrochemical performance at high mass loading above the commercial levels (10 mg cm−2). Herein, a unique 3D porous carbon with high mass loading is successfully prepared from Linum usitatissimum L. stem via a simple route of high temperature carbonization and subsequent KOH activation. The as-prepared porous carbon displays rich N/O heteroatoms, hierarchical porous, and interconnected vertical channels, which enable fast electron/ion transport and afford additional capacitance. These characteristics give the resultant carbon high capacitances of 434/245 F g−1 at 1/50 A g−1. Importantly, the as-prepared carbon can achieve mass loadings of 20 mg cm−2 and maintain decent electrochemical performance at this mass loadings, owing to short electron/ion transfer pathway as well as sufficient active sites. Specifically, the assembled symmetric supercapacitor delivers superior areal capacitance of 3.7 F cm−1 at 1 A g−1 and remarkably capacitance retention of 2.5 F cm−1 at 5 A g−1 under 20 mg cm−1. This work enlightens a sustainable and facile way for constructure advanced electrode material.

Pyridinic-N-rich carbon dots in IFE-based Turn-off Fluorometric detection of nerve agent Mimic- Diethyl chlorophosphate and multicolor cell imaging.

Fluorometric sensors for the detection of nerve agent mimics have received a lot of interest nowadays due to their high sensitivity and selectivity, ease of operation, and real-time monitoring. Pyridinic-N-rich carbon dots (NCDs) prepared through microwave-assisted pyrolysis of l-Malic acid and urea have been explored first time in this work as a novel turn-off fluorescent probe for the sensitive and selective detection of diethyl chlorophosphate (DCP), a nerve agent mimic. The as-prepared carbon dots contained a large amount of pyridinic nitrogen on their surface, which can modulate the photoluminescence properties of the NCDs. The blue emissive NCDs possessed both excitation wavelength-dependent and independent emission behavior. The detection of DCP was premised on quenching of the fluorescence emission intensity of NCDs in the presence of similar chemical reagents (e.g., trimethyl phosphate, triethyl phosphate, triethyl phosphonoacetate, triphenyl phosphate, diphenyl phosphate, tributyl phosphate). Fluorescence quenching of the NCDs in the presence of DCP has been attributed to the inner filter effect (IFE). From the linear Stern-Volmer plot (R2=0.9992), the limit of detection (LOD) was found to be 84μM for sensing DCP for the concentration ranging between 3 and 15mM. The biocompatibility of NCDs was assessed through cytotoxicity assay on MDA-MB-231 breast cancer cells. Fluorescence imaging demonstrated that NCDs have low cytotoxicity and can be employed successfully in cell imaging.

N-doped porous carbon derived from macadamia nut shell for CO2 adsorption

Selective adsorption and converting CO2 upon efficient solid-based adsorbents is critical for net-zero accomplishment. Herein, we develop an advisable strategy to prepare nitrogen-enriched porous carbons using the macadamia nutshell (MNS) as a carbon precursor, KOH as the activator and melamine as the nitrogen agent, respectively. The as-prepared porous carbons exhibit an enhanced specific surface area of 1731 m2/g and high microporosity with abundant nitrogen functional groups and structural defects. The CO2 uptake of 6.61 and 4.35 mmol g−1 were achieved at 0 and 25 °C, respectively, under 1 bar. More importantly, these biomass-based nitrogen-doped carbons possess various CO2 adsorption merits such as quick adsorption kinetics, high CO2/N2 selectivity, medium heat of adsorption, outstanding uninterrupted recyclability and good dynamic CO2 capture capacity. The present study provides an advanced protocol to design nitrogen-doped porous Carbon via a facile route toward the capture of CO2, which offers excellent progress in sustainable chemistry and engineering.

Biowaste-derived oxygen-self-doped three-dimensional interconnected porous carbon for electrochemical supercapacitor applications

ABSTRACT Biowaste for producing a biomaterial is an inexpensive, profuse, widely available, and viable natural source and has been extensively investigated and applied in a wide range of research fields. In this work, jackfruit leaf waste as a biowaste source was utilized to prepare a three-dimensional (3D) interconnected porous carbon framework self-doped with oxygen by KOH impregnation, carbonization, and activation under a CO2 atmosphere. The as-prepared porous carbon has a 3D interconnected porous framework with a rich oxygen content of 36.82%, and high BET surface area of 455.687 m2 g−1 with a pore volume of 0.522 cm3 g−1. The 3D interconnected porous framework exhibits a high specific capacitance of 199 F g−1 with a maximum energy density of 27.64 Wh kg−1 at a power density of 99.60 W kg−1 at a sweep rate of 1 mV s−1 in a two-electrode setup. The correlation between structure and great performance of electrode materials is deeply studied. The great capacitive performance of porous carbon materials can be assigned to its 3D interconnected porous framework, high specific surface area, suitable pore size distributions, and advantageous heteroatom-doping, resulting in the rapid ion diffusion and sufficient charge storage along with the contributed pseudocapacitance behavior. Hence, the exciting results reveal an efficient, cost-effective, time-saving, and facile method to prepare 3D interconnected porous carbon frameworks self-doped with oxygen derived from natural biowaste sources for developing supercapacitor devices.

Single step strategy to prepare highly microporous carbons derived from melamine and terephthalaldehyde for high-performance material-based hydrogen storage

Future energy sources like hydrogen (H2) have been viewed as a viable substitute for fossil fuels. To develop a sustainable H2 economy, efficient means of storing H2 is an urgent prerequisite. In this regard, materials-based H2 storage is a promising route to achieve United States Department of Energy goals. In the current work, a mixture of “melamine and terephthalaldehyde” undergoes simultaneous polymerization, carbonization, and in-situ activation in the presence of molten salt media (KOH + NaOH) by a single all-in-one approach to create microporous carbons with large specific surface areas (SSA ∼ 2462 m2/g), and total pore volume (∼1.96 cm3/g). As-prepared carbons with excellent textural features activated at 800 °C exhibit remarkable H2 storage capacities (up to 3.62 wt% at −196.15 °C and 1 bar, and 6.41 wt% at 30 bar). The results illustrated that pore size (0.68 nm) plays the dominant role in deciding H2 storage capacity at low pressure in comparison to total SSA and micropore volume. However, greater SSA and larger pores are thought to be the determining parameters for measuring H2 storage capacity at higher pressure (30 bar). Lastly, moderate values of isosteric heat of adsorption (Qst = 5.51–7.99 kJ/mol) demonstrate that H2 storage occur through physisorption.

Exploiting the Coordination Effect in Fe-Phenanthroline Complex for the Catalytic Carbonization of Phenanthroline toward the High Capacity Anode Grade Carbon

Aromatic organic molecules (AOMs) present an appealing precursor option for anode-grade hard carbon for sodium-ion batteries (SIBs) because of their prevalence, diverse chemical functionalities, and huge scope for nanostructure engineering at the molecular level. However, most small organic molecules decompose before actual carbonization is initiated unless reactions are carried out under high pressures or in the presence of catalysts. Herein, we report a facile carbonization of aromatic monomeric phenanthroline (phen) by exploiting the strong molecule-level coordination effect of the Fe-phen complex and in situ catalysis affected by Fe. With this carbonization strategy, we achieve better scalability with appreciable carbon yield, while carbonization of simple phen molecule returns zero carbon yields. The as-prepared N-doped microporous carbon (NMC) possesses desirable microstructural features with optimum nitrogen content to be employed as an anode for SIB. As an anode, the NMC delivers a high reversible capacity of 271 mAh g–1 at 100 mA g–1, an ultrahigh rate capability of 101 mAh g–1 at 1 A g–1, and a stable cycle life. The galvanostatic intermittent titration technique (GITT) depicts sodium ion diffusion coefficients of the order of ∼10–13 (cm2 s–1) in the intercalation region, which implies a faster sodium ion diffusion rate compared to most of the reported hard carbons. Given the vast diversity of AOMs, this work encourages new research interests to produce advanced carbon materials with nanostructure engineering at the molecular level for sodium-ion battery applications.

Cistanches herba residues derived nitrogen and oxygen self-doped porous carbon for high performance supercapacitor

Cistanches herba residues are successfully employed as starting materials to prepare porous carbon through pre-carbonization and KOH activation method. The effects of pre-carbonization, KOH activation, and pre-carbonization temperature are investigated. The optimal structure of as-prepared carbon has abundant micropores, high specific surface area (2767.2 m2 g−1), good affinity for electrolyte, and high content of self-doped O (29.09%) and N (1.37%). The supercapacitors constructed with the as-prepared carbon materials are able to exhibit good specific capacitance of 360.26 F g−1 at 1.0 A g–1 and 191.3 F g−1 at 100 A g–1 in 6.0 mol L−1 KOH electrolyte. Moreover, the as-prepared carbon-based supercapacitors also display good energy density of 21.72 Wh kg−1 (at 250 W kg −1) and achieve 100% specific capacitance retention after 13,000 cycles at 10 A g−1 in 1.0 mol L−1 H2SO4 electrolyte. Overall, this research presents a new avenue for high-value utilization of traditional Chinese medicine residues.

High graphitized N-doping porous carbon combined with bifunctional separator for the synergistic adsorption/conversion of polysulfides in Li–S batteries

Inferior conductivity of sulfur and inevitable shuttle effect of polysulfides are major obstacle of commercial application for Li–S batteries. Balancing the relation between adsorption effect and polysulfides synchronous conversion on the surfaces of metal oxides is crucial. Herein, a combination strategy with graphitized porous carbon and bifunctional separator is proposed for the multiple suppression of shuttle effect by the synergistic adsorption and synchronous conversion of polysulfides. Silk cocoon derived in-situ N-doping porous carbon and nano-TiO2/Super P decorated bifunctional separator are prepared by simultaneous activation/carbonization and surface coating approach, respectively. The unique lamellar porous carbon and nano-TiO2 effectively encapsulate active sulfur and immobilize polysulfides by the physical/chemical synergetic adsorption. The density functional theory calculations effectively testify that TiO2 with exposed (101) plane shows high chemical affinity toward polysulfides. Especially the as-prepared porous carbon shows an ultrahigh degree of graphitization that enhances the electronic conductivity. The TiO2/Super P-coated conductive bifunctional separator not only accelerates the electron transmission but also synchronously facilitates the redox conversion of polysulfides adsorbed on the TiO2 surface. Benefiting from the above structure merits, the optimized battery delivers high initial discharge capacity of 1311 mAh g−1 at 0.2C and good cycling stability with a low capacity decay of 0.037% per cycle at 1.0C as well as excellent rate capacity of 977 mAh g−1 at 2.0C. Even with 4.2 mg cm−2, the discharge capacity of 697 mAh g−1 is still retained after 70 cycles at 0.1C. This combination strategy exploits a novel way for the design and preparation of advanced lithium-sulfur batteries.

Duplex-specific nuclease powered 3D DNA walker and quantum dots barcodes for homogeneous electrochemical detection of microRNAs

Multiplex microRNAs (miRNAs) detection is beneficial for early diagnosis and prognosis of cancer. Herein, duplex-specific nuclease (DSN) powered 3D DNA walker and quantum dots (QDs) barcodes were designed for the simultaneous detection of miRNAs in a homogeneous electrochemical sensor. In the proof-of-concept experiment, the effective active area of the as-prepared graphene aerogel-modified carbon paper (CP-GAs) electrode was ∼14.30 times larger than that of the traditional glassy carbon electrode (GCE), endowing the enhanced capability of loading more metal ions for ultrasensitive detection of miRNAs. In addition, DSN-powered target recycling and DNA walking strategy assured the sensitive detection of miRNAs. After the introduction of magnetic beads (MNs) and electrochemical double enrichment strategies, the integration of triple signal amplification methods yielded good detection results. Under optimal conditions, towards simultaneous detection of microRNA-21 (miR-21) and miRNA-155 (miR-155), a linear range of 10−16–10−7 M and a sensitivity of 10 aM (miR-21) and 2.18 aM (miR-155) were achieved, respectively. It was worth mentioning that the prepared sensor can detect miR-155 down to 0.17 aM, which was also extremely advantageous among the sensors reported so far. What's more, through verification, the prepared sensor had good selectivity and reproducibility, and exhibited good detection ability in complex serum environments, showing great potential in early clinical diagnosis and screening.

Insights into the Use of Te–O Pairs as Active Centers of Carbon Nanosheets for Efficient Electrochemical Oxygen Reduction

Previous theoretical calculations have predicted that the incorporation of tellurium (Te) into carbon materials can significantly enhance their catalytic activity. Nevertheless, the experimental realization of efficient Te-doped carbon materials remains challenging. Here, we employed theoretical calculations to deduce the possible structure of Te-doped carbon materials. Our findings unveil that the formation of Te-O pairs in carbon materials with a relatively low oxygen coordination microenvironment can impart strong electron-donating capabilities, thereby boosting the electrocatalytic activity of oxygen reduction reaction (ORR). To verify our theoretical predictions, we synthesized Te-O pair-doped carbon materials using a tandem hydrothermal dehydration-pyrolysis strategy. This approach enabled efficient infiltration of Te into carbon materials. Our unconventional Te-O pair-doped carbon materials exhibit expanded interlayer distances and graphene-like nanosheet architectures, which provide enlarged active areas. These structural features contribute to the enhanced ORR catalytic performance of the as-prepared carbon catalyst. Our findings provide molecular-level insights into the design of various carbon-based electrocatalysts with binary-heteroatom-doped active sites.

Achieving purple light excitable high-efficiency temperature-responsive dual- and single-mode afterglow in carbon dots

Afterglow materials including thermally activated delayed fluorescence (TADF) and room temperature phosphorescence (RTP) have inspired extensive attention and research in anti-counterfeiting and sensing application prospects. However, a critical challenge currently remains within this afterglow materials only exhibit single-mode phosphorescence or delayed fluorescence with a persistent luminescence but low quantum yield. In this study, carbon dots composites with long-lived afterglow and ultra-high afterglow quantum yields of 193.5 ms and 35.07% were obtained by embedding the luminescent centers of ciprofloxacin into the formed rigid boric acid matrix by a one-step hydrothermal with purple light as the excitation wavelength. It is worth mentioning that the constructed composites exhibit dual-mode afterglow (DF and RTP) features at room temperature. Moreover, the carbon dots composites have distinctive temperature-responsive color-tunable properties and represent afterglow emission dominated by delayed fluorescence or phosphorescence at different temperatures. Based on the extraordinary temperature sensitivity, a single-mode ultra-long phosphorescence with a lifetime of up to 1.11 s is achieved at low temperatures. Additionally, as-prepared carbon dots composites exhibit the afterglow quantum yield of 40.97% in CB-VII, which is an ultra-high value for inorganic non-metallic materials. Furthermore, the resultant composites of carbon dots with new potential materials of encryption technology are designed for advanced information encryption and anti-counterfeiting applications.

Functional Carbon from Nature: Biomass-Derived Carbon Materials and the Recent Progress of Their Applications.

Biomass is considered as a promising source to fabricate functional carbon materials for its sustainability, low cost, and high carbon content. Biomass-derived-carbon materials (BCMs) have been a thriving research field. Novel structures, diverse synthesis methods, and versatile applications of BCMs have been reported. However, there has been no recent review of the numerous studies of different aspects of BCMs-related research. Therefore, this paper presents a comprehensive review that summarizes the progress of BCMs related research. Herein, typical types of biomass used to prepare BCMs are introduced. Variable structures of BCMs are summarized as the performance and properties of BCMs are closely related to their structures. Representative synthesis strategies, including both their merits and drawbacks are reviewed comprehensively. Moreover, the influence of synthetic conditions on the structure of as-prepared carbon products is discussed, providing important information for the rational design of the fabrication process of BCMs. Recent progress in versatile applications of BCMs based on their morphologies and physicochemical properties is reported. Finally, the remaining challenges of BCMs, are highlighted. Overall, this review provides a valuable overview of current knowledge and recent progress of BCMs, and it outlines directions for future research development of BCMs.

Solar pyrolysis of algae in molten salt for capacitive carbon preparation

Pyrolysis of algae in molten carbonates driven by concentrated solar energy is proposed as an economical and environmentally friendly method to obtain capacitive carbon for supercapacitors. The effects of molten carbonates on pyrolysis process and electrochemical performance at different temperatures (800, 850 and 900 °C) are investigated. Na2CO3–K2CO3 leads to a relatively high carbon yield and superior microstructure at around 900 °C compared with other molten salts, which is beneficial for capacitive carbon production. The as-prepared carbon possesses a high specific surface area of 2009.26 m2/g and a hierarchical porous structure mainly consisting of micropores and mesopores. Moreover, it contains abundant oxygen- and nitrogen-containing functional groups, such as CO, –OH, pyrrolic–N and quaternary–N. These features play an important multiple synergy for the preparation of desirable capacitive carbon, which has a high specific capacitance of 230.2 F/g at 0.25 A/g and a capacitance retention of 75.54% at 2 A/g. This work provides a green and promising approach for the production of heteroatom-doped capacitive carbon with superior porosity and specific surface area.

Preferential Pyrolysis Construction of Carbon Anodes with 8400 h Lifespan for High-Energy-Density K-ion Batteries.

Carbonaceous materials are promising anodes for practical potassium-ion batteries, but fail to meet the requirements for durability and high capacities at low potentials. Herein, we constructed a durable carbon anode for high-energy-density K-ion full cells by a preferential pyrolysis strategy. Utilizing S and N volatilization from a π-π stacked supermolecule, the preferential pyrolysis process introduces low-potential active sites of sp2 hybridized carbon and carbon vacancies, endowing a low-potential "vacancy-adsorption/intercalation" mechanism. The as-prepared carbon anode exhibits a high capacity of 384.2 mAh g-1 (90 % capacity locates below 1 V vs. K/K+ ), which contributes to a high energy density of 163 Wh kg-1 of K-ion full battery. Moreover, abundant vacancies of carbon alleviate volume variation, boosting the cycling stability over 14 000 cycles (8400 h). Our work provides a new synthesis approach for durable carbon anodes of K-ion full cells with high energy densities.

Synergistic effect of nitrogen and oxygen dopants in 3D hierarchical porous carbon cathodes for ultra-fast zinc ion hybrid supercapacitors

Zinc-ion hybrid supercapacitor is one of the most promising electrochemical energy storage devices for the applications needing both high energy densities and power densities. Nitrogen doping is an effective way to enhance the capacitive performance of porous carbon cathodes in zinc-ion hybrid supercapacitor. However, accurate evidence is yet needed to demonstrate how nitrogen dopants influence the charge storage of Zn2+ and H+ cations. Herein, we prepared 3D interconnected hierarchical porous carbon nanosheets by a one-step explosion method. The effect of nitrogen dopants on pseudocapacitance was analyzed by the electrochemical behaviors of as-prepared porous carbon samples with similar morphology and pore structure but different nitrogen and oxygen doping levels. Ex–situ XPS and DFT calculation demonstrate that nitrogen dopants promote the pseudocapacitive reactions by lowering the energy barrier for the change of oxidation states of carbonyl moieties. Owing to the improved pseudocapacitance by nitrogen/oxygen dopants and fast diffusion of Zn2+ ions in 3D interconnected hierarchical porous carbon matrix, the as-constructed ZIHCs show both high gravimetric capacitance (301 F g−1 at 0.1 A g−1) and excellent rate capability (a capacitance retention of 30% at 200 A g−1).