Nitrogen-doped Mesoporous Carbon Research Articles

Nitrogen-doped mesoporous carbon for high-performance zinc-iodine batteries

Nitrogen-doped mesoporous carbon for high-performance zinc-iodine batteries

Ordered Mesoporous Nitrogen Dope Carbon Synthesized from Aniline for Stabilization of Ruthenium Species in CO2 Hydrogenation to Formate

The hydrogenation of CO2 to produce formic acid has garnered increasing interest as a means to address climate change and promote the hydrogen economy. This research investigates the nanocasting technique for the synthesis of ordered mesoporous nitrogen-doped carbon (MNC-An). KIT-6 functioned as the silica template, while aniline served as the nitrogen–carbon precursor. The resultant MNC-An exhibits cubic Ia3D geometry, possesses significant mesoporosity, and has a high nitrogen content, which is essential for stabilizing ruthenium single atoms. The catalyst exhibited a specific activity of 252 mmolFAgcat−1 following a 2 h reaction at 120 °C. Moreover, the catalyst exhibited exceptional relative activity during five recycling experiments while preserving its catalytic efficacy. The atomically dispersed ruthenium and its Ru3+ oxidation state demonstrated perseverance both before and after the treatment. The results indicated that the synthesized catalyst possesses potential for the expedited commercialization of CO2 hydrogenation to produce formic acid. The elevated carbon yield, along with excellent thermal stability, renders it a viable substrate for attaching and stabilizing atomically dispersed ruthenium catalysts.

Improving H2S remediation efficiency through metal-free biochar modification: Nitrogen introduction and mesopore formation

Hydrogen sulfide (H₂S) poses substantial risks to human safety and infrastructure due to its toxicity and corrosive properties. In this study, we present a novel approach to enhance the selective catalytic oxidation of H₂S by synthesizing a nitrogen-doped mesoporous carbon catalyst (denoted as M/B-X-PZ-T) through pyrolysis at 600–800 °C. Our catalyst, derived from commercial biochar, incorporates melamine as a nitrogen source and employs KCl and ZnCl₂ as porogens via the salt-templating method. The resulting catalyst, M/B-1-PZ-700, exhibits an impressive specific surface area of up to 1269.77 m²/g and a high mesopore ratio, with effective nitrogen doping reaching up to 15.35 at%. Remarkably, M/B-1-PZ-700 demonstrated exceptional performance, achieving 100 % H₂S conversion and 94 % sulfur selectivity at 170 °C, surpassing previous nitrogen-doped carbon catalysts. Furthermore, our optimized catalyst maintained over 95 % H₂S conversion and superior sulfur yield for 36 h, indicating excellent long-term stability. This metal-free catalyst derived from biochar offers a promising, sustainable, and eco-friendly solution for effectively mitigating hazardous H₂S emissions.

Efficient atomically dispersed Fe catalysts with robust three-phase interface for stable seawater-based zinc-air batteries

The use of seawater-based electrolytes in zinc-air batteries (S-ZABs) presents significant economic and social benefits and mitigates the demand for scarce freshwater resources. However, it is challenging to achieve a metal-nitrogen-carbon (M-N-C) catalyst that exhibits high resistance to corrosive Cl- in seawater-based electrolytes and possesses a strengthened binding affinity with O2, which enables catalysts with an optimized oxygen reduction reaction (ORR) and enhances the applicability of S-ZABs. Herein, we propose a combined wet chemistry-pyrolysis strategy to obtain atomically dispersed Fe-decorated nitrogen-doped mesoporous carbon spheres (N-MCS-Fe-900). Benefiting from the capacity of the Fe decorations to form the edge-hosted aerophilic FeN4-O2 sites at the optimized three-phase interface, N-MCS-Fe-900 affords the enhanced resistance of the active Fe sites to corrosive Cl-, as well as improved interaction with O2, thereby facilitating the ORR process. As expected, the N-MCS-Fe-900 delivers high half wave potential of 0.90V and kinetic current density of 18.61mAcm−2 at 0.85V in seawater-based 0.1M KOH. More importantly, the S-ZABs equipped with N-MCS-Fe-900 exhibited long-term stability under a high current density for over 140h without voltage decay. Theoretical calculations and electrochemical performance evaluations collectively revealed the superior catalytic efficacy and genesis of this activity in N-MCS-Fe-900, which features edge-hosted FeN4-O2 sites at the stable three-phase interface in seawater electrolytes. This study provides new insights for the advancement of ORR catalysts in sustainable energy conversion technologies for seawater-based electrolytes.

Nitrogen-doped mesoporous carbon as metal-free catalysts for the aerobic oxidation of alcohols

The selective oxidation of alcohols to carbonyl compounds is a crucial reaction in organic chemistry. In this study, we report the synthesis of nitrogen-doped mesoporous carbon material by hard template method using biomass derivative sucrose and melamine as carbon and nitrogen sources and silica sol as template agent. Using molecular oxygen as the oxidant, the obtained NC-900 exhibits excellent selectivity in the oxidation of primary alcohols to the corresponding aldehydes without generating over-oxidized acid. For example, under optimal reaction conditions, 4-methoxybenzyl alcohol is almost quantitatively converted to 4-methoxybenzaldehyde. The catalytic system showed robust tolerance to sensitive functional groups and demonstrated favorable reaction effects in gram-scale experiments and multi-step, one-pot reaction sequences. The catalyst was reused for 5 times, and its catalytic activity did not decrease significantly. Hammett correlation studies indicated that the reaction favored substrates with electron-donating substituents. Characterization and experimental results indicate that the synergistic effect of graphitic N and mesoporous structure plays a pivotal role in enhancing the catalytic activity of NC-900 in this transformation. The mechanism study shows that the reaction involves free radical process.

Development of Bromine Adsorbing Carbon Felt Electrode by Coating of Nitrogen-Doped Mesoporous Carbon Layer for Highly Stable Flowless Zinc-Bromine Battery

Renewable energy is well known for the extreme volatility of power production, and secondary battery-based energy storage systems (BESS) are the key to the novel and safe energy industry to expand the supply of renewable energy. Currently, lithium-ion battery-based ESS is commonly used, but the frequent ignition accidents from these ESSs rather become an obstacle to the growth of the renewable energy field. Among the redox batteries, the flowless zinc-bromine battery (FLZBB) is studied as the alternative since it uses a non-flammable and cost-effective aqueous Zn- Br2 electrolyte. However, its main challenges are that bromine (Br2) and polybromide anions (), formed at the positive electrode during the charging process, cross over to the negative electrode due to the difference in chemical potential between the electrodes. The diffused Br2 oxidizes the zinc metal, electrodeposited on the negative electrode, and causes a self-discharge reaction that consumes the charging active material and Br2 the battery performance and life. Herein, we present a nitrogen-doped mesoporous carbon coated on the pristine graphite felt fibers (NMC/GF). By uniformly forming a nitrogen-doped porous carbon material on the GF fibers through the evaporation-induced self-assembly (EISA) method, it is a simple and cost-effective method to develop the structural and properties of the GF positive electrode to increase the ability of adsorption and storing the active materials, Br2 and polybromide anions (,, and ) generated during the charging process. In addition, it also improved the bromine redox reaction kinetics by having a strong affinity with the aqueous Zn-Br2 electrolyte. This facilitates long-term charge/discharge cycles, enabling high performance and improved durability for Coulombic efficiency over 95% for 5000 cycles in the FLZBB single-cell platform at a current density of 20 mA cm-2 and a high-rate areal capacity of 2 mAh cm-2.

Atomically dispersed ternary FeCoNb active sites anchored on N-doped honeycomb-like mesoporous carbon for highly catalytic degradation of 4-nitrophenol

In the last decades, 4-nitrophenol is regarded as one of highly toxic organic pollutants in industrial wastewater, which attracts great concern to earth sustainability. Herein, atomically dispersed ternary FeCoNb active sites were incorporated into nitrogen-doped honeycomb-like mesoporous carbon (termed FeCoNb/NHC) by a two-step pyrolysis strategy, whose morphology, structure and size were characterized by a set of techniques. Further, the catalytic activity and reusability of the as-prepared FeCoNb/NHC were rigorously examined by using 4-NP catalytic hydrogenation as a proof-of-concept model. The influence of the secondary pyrolysis temperature on the catalytic performance was investigated, combined by illuminating the catalytic mechanism. The resultant catalyst exhibited significantly enhanced catalytic features with a normalized rate constant (kapp) of 1.2 × 104 min-1g−1 and superior stability, surpassing the home-made catalysts in the control groups and earlier research. This study provides some constructive insights for preparation of high-efficiency and cost-effectiveness single-atom nanocatalysts in organic pollutants environmental remediation.

Application of Mesoporous Carbon-Based Highly Dispersed K-O2 Strong Lewis Base in the Efficient Catalysis of Methanol and Ethylene Carbonate.

As an atom-economical reaction, the direct generation of dimethyl carbonate (DMC) and ethylene glycol (EG) via the transesterification of CH3OH and ethylene carbonate (EC) has several promising applications, but the exploration of carriers with high specific surface areas and novel heterogeneous catalysts with more basic sites remains a long-standing research challenge. For this purpose, herein, a nitrogen-doped mesoporous carbon (NMC, 439 m2/g) based K-O2 Lewis base catalyst (K-O2/NMC) with well-dispersed strongly basic sites (2.23 mmol/g, 84.5%) was designed and synthesized. The compositions and structures of NMC and K-O2/NMC were comprehensively investigated via Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, N2 adsorption-desorption, CO2 temperature-programmed desorption, and contact angle measurements. The optimal structural configuration and electron cloud distribution of the K-O2/NMC catalyst were simulated using first-principles calculations. The electron transfer predominantly manifested as a flow from K-O to C-O/C-N, and the interatomic interactions between each atom were enhanced and exhibited a tendency for a more stable state after redistribution. Furthermore, the adsorption energies (Eads) of CH3OH at K-O-O and K-O-N sites were -1.4185 eV and -1.3377 eV, respectively, and the O atom in CH3OH exhibited a stronger adsorption tendency for the K atom at the K-O-O site. Under the optimal conditions, the EC conversion, DMC/EG selectivity, and turnover number/frequency were 80.9%, 98.6%/99.4%, and 40.5/60.8 h-1, respectively, with a reaction rate constant (k) of 0.1005 mol/(L·min). Results showed that the heterogeneous K-O2/NMC catalyst prepared herein greatly reduced the reaction cost while guaranteeing the catalytic effect, and the whole system required a lower reaction temperature (65 °C), a shorter reaction time (40 min), and a lower catalyst amount (2.0 wt % of EC). Therefore, K-O2/NMC can be used as a catalyst in different transesterification reactions.

Nitrogen-doped mesoporous carbon combined with carbon nanotubes as counter electrode catalysts for quantum dot sensitized solar cells with record efficiency

The fabrication of a counter electrode possessing elevated catalytic efficiency and steadfast stability is a crucial prerequisite for the high-performance quantum dot sensitized solar cells (QDSCs). Mesoporous carbon (MC) has been adopted as the desired CE material in the past years, but the disadvantage of its poor conductivity has limited further development of the performance of QDSCs. In this study, we present a straightforward approach for producing highly effective counter electrodes through the integration of nitrogen-doped mesoporous carbon (N-MC) with carbon nanotubes (CNTs), forming a composite material that is deposited onto a titanium mesh substrate. The counter electrode (CE) based on composite materials shows excellent electrocatalytic performance, synergistically benefiting from large specific areas of N-MC and high conductivity of CNTs. Electrochemical measurements reveal that the optimal CEs exhibit excellent catalytic reduction activity as well as high electron mobility. Consequently, the corresponding QDSCs show a record power conversion efficiency of 16.68 %.

Novel highly utilized PdNi bimetallic-loaded N-doped carbon catalysts prepared from MOF for Suzuki coupling reaction and hydro reduction of nitroaromatics

The usage of palladium-based catalysts in numerous chemical reactions has been increased significantly; in particular, the synthesis of heterogeneous catalysts by attaching palladium atoms to carriers has expanded rapidly. Therefore, the selection of nitrogen-doped carbon materials for carriers has become a popular research subject. In this study, Ni-Ni PMOF was first created, then Ni nanoparticles (NPs) modified nitrogen-doped mesoporous carbon materials were synthesized through pyrolysis. Subsequently, Pd atoms were successfully deposited onto the surface of Ni NPs as Pd2+ is capable of being reduced by metal Ni. The structure of the prepared carriers was verified by FT-IR, XRD, SEM, TEM, XPS and other characterizations, and was found to have a fluffy and porous structure that increases the number of active sites of PdNi NPs. This material was found to be effective in catalyzing the Suzuki coupling reaction (TOF = 1019 h) and the reduction reaction of p-nitrophenol (Kapp = 4.34 × 10−2 s−1), and its catalytic activity remained stable even after 10 uses, showing good recoverability and recyclability. This study thus provides a novel approach for the preparation of N-doped porous carbon materials, which can enable green chemistry by making efficient and full use of precious metals.

Influence of the Nitrogen Precursor in the Development of N-Functionalities in a Mesoporous Carbon Material and Its Effect on the Li–S Cells’ Electrochemistry

Li–S batteries are positioned as a strong alternative for efficient energy storage due to their high theoretical energy density and their theoretical specific capacity (1675 mA h g−1) compared to current Li-ion batteries; however, their commercialization is affected by the rapid decay of the specific capacity as a consequence of the different species of lithium polysulfides that are generated during the charge–discharge processes. The use of nitrogen-doped mesoporous carbon materials has been shown to have the ability to confer electronic conductivity to sulfur and retain the lithium polysulfide species. However, there are not enough studies to help understand how the type of nitrogen precursor influences the development of specific nitrogen functionalities to favor the retention of lithium polysulfide species. This work seeks to determine the effect of the use of different nitrogen precursors on the structural changes of the mesoporous carbon materials prepared, and thus evaluate the electrochemical behavior of Li–S cells correlating the type of nitrogen functionality generated when the precursor is variated with the charge/discharge capacity developed during the cell operation. For this study, different carbon materials were prepared by the variation of the nitrogen source (melamine, ethylenediamine, and hexadecylamine) to obtain a N-doped mesoporous carbon with different distributions of nitrogen functionalities in its structure. The use of the primary amine ethylenediamine as a nitrogen precursor in the formation of structured carbon materials favored elemental sulfur infiltration into its pores, resulting in the maximum sulfur content within the pores and interacting with the carbonaceous matrix (78.8 wt.%). The carbon material prepared with this precursor resulted in a higher content of N-pyridinic functionality, which, combined with the high content of N-pyrrolic, resulted in the highest specific discharge capacity at 0.1 C after 100 cycles when compared to cells assembled with materials derived from the use of melamine and hexadecylamine precursors. The cell assembled with the electrode formed from ethylenediamine as a nitrogen precursor presented an initial discharge capacity of 918 mA h g−1 with a Coulombic efficiency of ~83.4% at 0.1 C after 100 cycles.

Precisely Designed Nitrogen-Doped Mesoporous Carbon Sphere-Confined Electron-Deficient Pd Nanoclusters with Enhanced Catalytic Hydrogenation Performance

Precisely Designed Nitrogen-Doped Mesoporous Carbon Sphere-Confined Electron-Deficient Pd Nanoclusters with Enhanced Catalytic Hydrogenation Performance

Nitrogen-doped magnetic porous carbon nanospheres derived from dual templates-induced mesoporous polydopamine coated Fe3O4 for efficient extraction and sensitive determination of volatile nitrosamines by gas chromatography-mass spectroscopy

N-nitrosamines (NAs) are highly carcinogenic compounds commonly found in food, beverages, and consumer products. Due to their wide polarity range, it is challenging to find a suitable carbon adsorbent that can simultaneously adsorb and enrich both polar and nonpolar NAs with good recovery. In this study, nitrogen-doped magnetic mesoporous carbon nanospheres (M-MCN) were prepared and employed as an adsorbent for magnetic solid-phase extraction (MSPE) to extract and concentrate four NAs. The introduction of nitrogen functional groups enhanced the hydrophilicity of the carbon material, allowing M-MCN to achieve a balance between hydrophilicity and hydrophobicity, resulting in good recovery for both polar and nonpolar NAs. A method combining MSPE with gas chromatography-mass spectrometry (GC-MS) was developed for the determination of NAs in processed meat and alcoholic beverages. The method exhibited a good linear range (1–100 ng g−1, r2 > 0.9967) and trace-level detection (0.53–6.6 ng g−1). The recovery rates for the four NAs ranged between 85.7 and 110.7 %, with intra-day precision expressed as relative standard deviation (RSD) between 4.1 and 10.7 %, and inter-day precision between 4.8 and 12.9 %. The results demonstrated not only good accuracy and precision but also provided a new adsorbent for the enrichment of trace-level NAs in processed meat and alcoholic beverage samples.

A magnetic imprinted polymer nano-adsorbent with embedded quantum dots and mesoporous carbon for the microextraction of triazine herbicides

A magnetic molecularly imprinted polymer (MMIP) adsorbent incorporating amino-functionalized magnetite nanoparticles, nitrogen-doped graphene quantum dots and mesoporous carbon (MIP@MPC@N-GQDs@Fe3O4NH2) was fabricated to extract triazine herbicides from fruit juice. The embedded magnetite nanoparticles simplified the isolation of the adsorbent from the sample solution. The N-GQDs and MPC enhanced adsorption by affinity binding with triazines. The MIP layer provided highly specific recognition sites for the selective adsorption of three target triazines. The extracted triazines were determined by high-performance liquid chromatography (HPLC) coupled with diode-array detection (DAD). The developed method exhibited linearity from 1.5 to 100.0 µg L−1 with a detection limit of 0.5 µg L−1. Recoveries from spiked fruit juice samples were in the range of 80.1– 108.4 %, with a relative standard deviation of less than 6.0 %. The developed MMIP adsorbent demonstrated good selectivity, high extraction efficiency, ease of fabrication and use, and good stability.

FeCo alloy nanoparticles supported on N-doped mesoporous carbon spheres for effective degradation of antibiotics and industrial dyes

Iron (Fe) is widely recognized for its effectiveness in the Fenton reaction and is commonly used in wastewater treatment. However, exploring other metals in similar Fenton-like reactions has been relatively limited. FeCo alloy nanoparticles (NPs), anchored on nitrogen-doped mesoporous carbon spheres (FeCo/NMCS), have been effectively synthesized and used as a Fenton-like catalyst in wastewater treatment under alkaline conditions. The NMCS exhibited spherical with an average diameter of 488.1 nm, while the FeCo alloy NPs, uniformly distributed over the NMCS, had an average diameter of 8.2 nm. The mesopores served as anchoring points for the NiCo alloy NPs, effectively preventing their possible agglomeration. The NMCS was composed of 3.91 wt% nitrogen. With 30 mg of FeCo/NMCS and 25 mM H2O2, more than 92% of tetracycline hydrochloride (TC) was degraded within 35 min at pH levels 7, 9, and 11. The remarkable degradation rate was attributed to the dual active sites present in the FeCo alloys. The rapid degradation of TC, even at pH 11, indicates the potential of FeCo/NMCS as a valuable solution for wastewater treatment under alkaline conditions. Industrial reactive (Y145, R195, B222A) and disperse dyes (O30, R167, B79) with a concentration of 10 ppm were degraded within 20 min when using 10 mg of the FeCo/NMCS catalyst and 25 mM H2O2 at pH 9. After five consecutive TC degradation cycles at pH 7 and 9, the FeCo/NMCS demonstrated consistent performance, emphasizing its reusability. FeCo/NMCS provides a promising solution to pollution control and wastewater treatment with stability, superior catalytic activity, magnetic separability, and recyclability.

Achieving unprecedented cyclability of flowless zinc-bromine battery by nitrogen-doped mesoporous carbon on thick graphite felt electrode

The flowless zinc-bromine battery (FLZBB) is non-flammable as it is based on an aqueous electrolyte and is considered an alternative to redox flow batteries because of its cost-effectiveness using a simple cell platform. However, it faces challenges related to self-discharge caused by the crossover of bromine (Br2) and polybromide anions (Brn+2-) formed at the positive electrode during the charging process. The self-discharge reaction consumes the charging active materials, thereby decreasing battery performance and lifespan. To address the critical issues, this study introduces the development of a revolutionary positive electrode: a nitrogen-doped mesoporous carbon-coated thick graphite felt (NMC/GF). This positive electrode effectively suppresses the crossover of active materials and prevents the self-discharge reaction. The mesopores, strategically embedded with nitrogen sites, serve as a stronghold, capturing and immobilizing bromine and polybromide anions, significantly reducing their undesirable effects. Furthermore, we enhanced the electrochemical performance of the NMC/GF electrode by modifying it to be ultrahydrophilic. Abundant oxygen and nitrogen functional groups were incorporated onto the electrode, resulting in an amplified affinity with the aqueous electrolyte. This modification led to improved bromine redox reaction kinetics. Demonstrating an excellent Coulombic efficiency surpassing 96 % and an energy efficiency of over 76 % at a current density of 20 mA cm−2 with a high-rate areal capacity of 2 mAh cm−2, this novel positive electrode achieves a previously unattained milestone; cyclability unprecedentedly extended to 10,000 cycles. The development of NMC/GF positive electrodes further advances the FLZBB system, and large-area scale-up research of these carbon electrodes makes looking forward to practical uses in energy storage systems.

Controllable fabrication of N-doped carbon nanotubes coated Co4N nanoparticles to boost hydrogen evolution reaction

Transition metal nitrides (TMNs) have attracted great attention as ideal active materials in the field of electrocatalysts in recent years due to their excellent electrical conductivity, wide band gap and adjustable morphology. Pure phase Co4N nanoparticles encapsulated nitrogen-doped carbon (NC) nanotubes (Co4N@NC) were in-situ synthesized by one-pot method. In this paper, the morphology of carbon nanotubes is controlled by adjusting the pyrolysis time, so that more active sites are exposed on carbon nanotubes. Thus, the cobalt nitride catalyst with excellent catalytic performance for hydrogen evolution reaction (HER) in acidic electrolyte was obtained. In summary, due to the protection of mesoporous nitrogen-doped carbon to Co4N nanoparticles, large electrochemically active surface area, good conductivity and more exposed active sites, Co4N@NC possesses excellent HER performance in acidic electrolytes. The overpotential of Co4N@NC at the current density of 10 mA cm−2 is 117 mV (η10), and it shows long-term stability in 0.5 M H2SO4 solution for 50 h. This study provides a strategy for the development of catalysts for the controllable synthesis of high-performance transition metal nitrides.

Defect engineering enables an advanced separator modification for high-performance lithium-sulfur batteries

High-energy–density lithium-sulfur batteries have been rated as a promising, yet challenging, next-generation battery technology. Typically, the serious shuttle of polysulfide intermediates and sluggish solid–solid reaction kinetics often result in irreversibly sulfur loss, low Coulombic efficiency, and limited lifespan. Herein, we propose a facile and efficient separator modification strategy using a rationally designed sulfiphilic and lithiophilic mediator, i.e. in-situ confinement growth of oxygen-deficient TiO2-x nanoparticles within nitrogen-doped mesoporous carbon matrix to modulate the sulfur electrochemistry. The nanoscale defective catalyst within open mesoporous host affords favorable adsorption of polysulfides and catalytic conversion ability. Moreover, the versatile composite improves the electrolyte wettability and Li+ transfer kinetics and alleviates self-discharge behavior. Resultantly, the Li-S batteries using modified separator achieves significantly improved cycling stability with a low capacity decay of only 0.067% per cycle after 500 cycles at 2C. The defect engineering together with separator modification strategies enable efficient and durable Li-S batteries.

Metal-Free Nitrogen-Doped Mesoporous Carbons for the Mild and Selective Synthesis of Pyrroles from Nitroarenes via Cascade Reaction.

The cascade synthesis of pyrroles from nitroarenes is an attractive alternative strategy. However, metal catalysts and relatively high temperatures cover the existing reported catalytic systems for this strategy. The development of nonmetallic heterogeneous catalytic systems for the one-pot synthesis of pyrrole from nitroarenes under mild conditions is both worthwhile and challenging. Herein, we describe an exceptionally efficient method for the synthesis of N-substituted pyrroles by the reductive coupling of nitroarenes and diketones over heterogeneous metal-free catalysts under mild conditions. Nonmetallic NC-X catalysts with high activity were prepared from the pyrolysis of well-defined ligands via simple sacrificing hard template methods. Hydrazine hydrate, formic acid, and molecular hydrogen can all be used as reducing agents in the hydrogenation/Paal-Knorr reaction sequence to efficiently synthesize various N-substituted pyrroles, including drugs and bioactive molecules. The catalytic system was featured with good tolerance to sensitive functional groups and no side reactions such as dehalogenation and aromatics hydrogenation. Hammett correlation studies have shown that the electron-donating substituents are beneficial for the one-pot synthesis of N-substituted pyrroles. The results established that the outstanding performance of the catalyst is mainly attributed to the contribution of graphitic N in the catalyst as well as the promotion effect of the mesoporous structure on the reaction.

Nitrogen-doped mesoporous carbon spheres decorated with NiCo alloy nanoparticles for high-performance electrochemical supercapacitors

Nitrogen-doped mesoporous carbon spheres (NMCSs) decorated with NiCo alloy nanoparticles (NiCo/NMCS) were prepared and examined for their prospective role as high-performance electrode materials. The average size and BET surface of the NMCSs are 488.1 nm and 660.9 m2g−1. The N content of the NMCSs and NiCo/NMCS-50 (NMCSs with 50 wt% of NiCo alloy nanoparticles (NPs)) was 1.49 wt% and 2.9 wt%, respectively. The NiCo alloy NPs, with an average diameter of 9.6 nm, were evenly incorporated into NMCSs. The NiCo/NMCS-50 exhibited a specific capacitance of 585 F g−1 when tested in a 6 M KOH solution at a current density of 1 A/g. The superior electrochemical performance of NiCo/NMCS-50 is attributed to the synergistic effect of mesoporous carbon structure and NiCo alloy NPs by improving redox-related mass transport and electron transfer. Symmetric supercapacitor devices assembled using two NiCo/NMCS-50 electrodes had a maximum energy density of 30.0 Wh kg−1 at a power density of 187.5 W kg−1 with notable cycling stability, maintaining 60.1 % of capacitance, up to 5,000 cycles. These results suggest that NiCo/NMCS composites have significant potential for utilization in high-energy storage applications.