Hierarchical Porous Carbon Materials Research Articles

Fenton Reaction Doubled Biomass Carbon Activation Efficiency for High‐Performance Supercapacitors

AbstractThe huge consumption of alkali during biomass‐derived porous carbon production leads to pollution and high carbon‐emission. This study employs the concept of Fenton chemistry to achieve hierarchical porous biomass carbon materials with a remarkably high specific surface area of 3440 m2 g−1 with double activation efficiency compared to traditional activation process. The optimized carbon electrode demonstrates exceptional specific capacitance of 425.2 F g−1at a current density of 0.1 A g−1 and great rate performance (286.1 F g−1 at 100 A g−1) in 6 m KOH electrolyte. The enabled supercapacitor demonstrates remarkable cycling stability, retaining up to 99.74% of its initial capacitance after undergoing 20 000 charge–discharge cycles. In addition, the electrolyte ion distribution in different pore structures is simulated using Molecular Dynamics, which confirms that the structure is conducive to the rapid diffusion of ions, thus matching the excellent electrochemical properties. The assembled symmetric supercapacitors achieve a maximum energy density of 42.1 Wh kg−1 (12.1 Wh kg−1 based on cell stack mass) in TEABF4/AN electrolyte. This work presents an effective technique for the formation of porous structures from biomass precursors. The novel methodology can be applied to many other similar systems for energy storage and beyond.

Utilizing bamboo shoot shells to develop hierarchical porous carbon materials for high–performance supercapacitor applications

Hierarchical porous carbon materials were synthesized from bamboo shoot shells via KOH activation. The physicochemical properties of bamboo shoot shell–based hierarchical porous carbon (BBCK) were investigated by scanning electron microscopy, X–ray diffraction, Raman spectroscopy, X–ray photoelectron spectroscopy, and N2 adsorption–desorption analyses. Results confirmed that the ratio of KOH to BBCK significantly affected the pore structure, O content and electrochemical properties of BBCK. The obtained BBCK exhibited a specific surface area of 1394 m2 g–1 and a pore volume of 0.58 cm3 g–1. The O content of BBCK was 25.09%. The formation mechanism of BBCK, which had a hierarchical porous structure via KOH activation, was illustrated systematically. The specific capacitance was 320.05 F g–1 at 0.5 A g–1 in the 6 M KOH electrolyte, and multiplicity performance was 75.22% at 10 A g–1. The assembled symmetric supercapacitors demonstrate the power density was 250 W kg–1, and the energy density was 7.36 Wh kg–1. After 7000 cycles, the capacitance retention rate at 100%.

In-situ template method to synthesize metal/non-metal doped carbon for SO2 adsorption at low concentration: DFT and experimental studies

SO2 is one of the most significant air molecular contaminants (AMC). The development of materials for capturing low-concentration SO2 at room temperature is of great importance for industrial production and environmental safety. In this study, hierarchical porous carbon materials with Zn–N–C active structures were synthesized in one step using an in-situ template method. Among them, Zn/AC-2 exhibited a high specific surface area (1143.73 m2/g) and micropore volume (0.42 cm3/g). Dynamic adsorption tests were conducted under the conditions of an inlet concentration of 90 ppm, with a temperature of 23 °C and a humidity of 50%. The results indicated that the material showed an excellent capturing performance for SO2, with a breakthrough adsorption capacity of 3.37 mmol/g. Through characterization techniques including XPS, XRD, and SEM-EDS, it was found that the metal elements were dispersed in atomic form within the carbon framework, demonstrating the effectiveness of the modification method. A comparative study of the new adsorbent and spent adsorbent proved that SO2 reacts with extremely high catalytic efficiency on the material surface to generate SO3, revealing the reaction mechanism on the material surface. Finally, based on density functional theory, the microscopic reaction mechanism of the interaction between SO2 and the prepared material surface was studied at the molecular level. The results showed that the reaction energy barrier on the material surface is only 1.01 eV, and the reaction releases 3.14 eV of energy, indicating that the reaction can spontaneously occur at room temperature.

PDA@UiO-66-NH2-derived nitrogen and oxygen-doped hierarchical porous carbon for efficient adsorption of BPA and dyes

MOF-derived carbon materials have garnered significant attention in the field of adsorption due to their abundant porosity, excellent stability, and structural diversity. In this study, nitrogen and oxygen-doped hierarchical porous carbon materials were obtained by carbonizing PDA@UiO-66-NH2 at various temperatures and subsequently etching with hydrofluoric acid for different times. The adsorption capacity of these materials towards bisphenol a (BPA), methyl orange (MO), and methylene blue (MB) was evaluated. The results suggest excessive carbonization temperature and etching time may cause the collapse of the pore structure. In addition, the introduction of a PDA carbon layer can reduce the nitrogen–oxygen ratio and modify the nitrogen species in the materials. Among these materials, UPCH800, which was carbonized at 800 °C followed by etching for 6 h, exhibits the best adsorption performance towards BPA and MO, with a maximum adsorbed amount of 350.51 and 417.34 mg/g respectively. For MB, the maximum adsorption amount is 227.53 mg/g. All adsorptions reach equilibrium within 1 h. Thermodynamic studies reveal that the adsorption of MO by UPCH800 is an entropy-driven adsorption process, while the adsorption of BPA and MB is an enthalpy-driven exothermic process. Based on experimental and characterization results, the primary adsorption mechanisms involve π-π interactions, n-π interactions, pore-filling, and hydrogen bonding between the pollutants and the material. Moreover, UPCH800 exhibits high removal efficiency after 5 adsorption cycles, making it a promising material for the adsorption of BPA and MO.

Green one-pot synthesis of spongy hierarchical porous carbon with interconnected channels towards high-performance supercapacitors

Green and convenient construction of three-dimensional (3D) hierarchical porous carbon for supercapacitors (SCs) has drawn widespread attention due to their effective ion adsorption and transport capabilities. In this study, sucrose-derived spongy hierarchical porous carbon materials were successfully prepared using a one-step carbonization process with sodium chloride and sodium bicarbonate acting as collaborative pore-forming agents. The optimal carbon material exhibits a distinct 3D spongy structure with interconnected channels, high specific surface area, and proper pore size distribution. Consequently, it displays a specific capacitance of 263.5 F g−1 at 0.5 A g−1 and could retain 221.9 F g−1 (84.21%) at 20 A g−1. Additionally, the as-fabricated device delivers a supreme energy density of 17.0 Wh kg−1 at 80 W kg−1 and possesses exceptional cycling stability of 94.36% after 20000 cycles. Through the combination of raw material carbonization properties and synergistic pore-making mechanisms, the present work provides an effective and eco-friendly approach for fabricating 3D spongy hierarchical porous carbon materials with interconnected channels for high-performance SCs.

Designing hollow mesoporous carbon sphere for high-rate supercapacitor in water-in-salt electrolyte

The expansion of the operational voltage in supercapacitors (SCs) through the utilization of water-in-salt electrolytes (WISEs) has garnered considerable attention for achieving elevated energy density. However, the poor rate performance of assembled SCs persists due to the heightened viscosity of WISEs (e.g., 17.0 mol kg−1 NaClO4), so designing the porous structure of electrode materials to improve the rate performance of SC in WISEs has become a research focus. In this study, we present a straightforward approach to fabricate hierarchical porous carbon spheres, designing to expedite ion infilling and transport within WISE-based SCs. The hollow porous carbon is synthesized via one-step pyrolysis process, wherein the decomposition of inner colloid particles yields gases, while the outer resorcinol–formaldehyde resin carbonizes to form a spherical shell. In the WISE of 17.0 mol kg−1 NaClO4, the resulting symmetric SCs exhibit an operational voltage of 2.6 V and significantly improved rate capability with a capacitance retention of 47.7 % at 100 A g−1. Notably, the energy density can reach 31.0 Wh kg−1 at a power density of 2.4 kW kg−1. Even under high power density conditions of 120.0 kW kg−1, the energy density of 14.7 Wh kg−1 can remain. Additionally, the SC device manifests an impressive capacitance retention of 99.1 % after 20,000 cycles, showcasing exceptional cyclic stability. This research introduces a novel synthesis strategy for hierarchical porous carbon materials, enabling the development of high-rate SCs with both elevated energy density and power density.

One-step molten salt-assisted preparation of crab shell-based hierarchical porous carbon for capacitive energy storage

Carbon-based materials have become the most commonly used electrode materials for supercapacitors due to their simple production and low preparation cost. The preparation of hierarchical porous carbon materials with excellent properties using biomass materials is a very valuable study. Therefore, we used crab shells as carbon precursors to prepare crab shell-based carbon materials by using the self-templating method (CaCO3) combined with low-temperature eutectic molten salt. When the composition of the eutectic salt was CaCl2/KCl (molar ratio of 43:57) and the mass ratio of crab shells to eutectic salt was 1:5, the prepared crab-shell-based carbon material (CC-CaK-5) exhibited excellent physical and electrochemical properties with high specific surface area (1193.7 m2g−1), rich heteroatom doping (O (7.83 %) and N (6.71 %)), and high specific capacitance (290 Fg−1 at 0.5 Ag−1).The CC-CaK-5//CC-CaK-5 devices assembled with CC-CaK-5 as the electrode material exhibited excellent electrochemical performance. At a current density of 1 Ag−1, the capacitance value of the device remained at 93.11 % of the initial capacitance value after 5000 cycles. The energy density reached 6.95 Whkg−1 at a power density of 302.09 Wkg−1 and remained at 4.71 Whkg−1 at a power density of 13,037.54 Wkg−1.

Polyacrylonitrile-sodium lignosulfonate -derived nitrogen-doped three-dimensional hierarchical porous carbon for supercapacitors

Modulation of pore structure and heteroatom doping are very important strategies to improve the electrochemical properties of carbon electrode materials. This report investigates the use of biomass-derived nitrogen-doped porous carbon materials to address the challenge of the specific capacitance and energy density in supercapacitors. Nitrogen-doped three-dimensional hierarchical porous carbon materials were prepared using a polyacrylonitrile/sodium lignosulfonate composite monolith as a precursor by thermally induced phase separation and subsequent carbonization/activation. This method precisely controls the structure and surface properties of porous carbon materials by regulating the structure of the precursor and situ doping of nitrogen, which is a valuable strategy for the controllable regulation of the pore structure for nitrogen-doped porous carbon materials. The resulting carbon material displayed excellent capacitance performance, exhibiting a high specific capacitance of 325.7F g -1 at a current density of 0.5 A/g, maintaining initial capacitance retention of 90.1 % at a current density of 5 A/g after 10,000 cycles. When investigated for practical applications, the assembled supercapacitor device had a higher energy density (9.88 W h kg- 1), which is higher than commercial carbon-based supercapacitors.

A hierarchical porous N-doped carbon material as catalyst derived from the folic acid-Zn/KBr hydrogel: Reaction network and kinetics and mechanism for the oxidation of furfural to maleic acid

A novel hydrogel (named FA-Zn/KBr) was prepared, by taking advantage of the hydrogen-bonding and π-π stacking interactions between the pterin heterocycles of the folic acid (FA) molecules. The hydrogel is composed of highly dispersed KBr, coordinated zinc ions, and stacked arrays of folate tetramers. Due to the presence of KBr, a hierarchical porous nitrogen-doped carbon (PNC-800) material with a specific surface area 2807.9 m2/g can be formed through the calcination of the FA-Zn/KBr xerogel under N2. PNC-800 is used to catalyze the oxidation of furfural to maleic acid in the presence of H2O2. Representative nine reactions constitute the reaction network. The reaction rate constants and apparent activation energy were obtained for each reaction. Based on the kinetics parameters, the simulated results are in good agreement with the experimental data. The mechanism of the reaction catalyzed by PNC-800 is proposed based on ample experimental evidence. The graphitic nitrogen species in PNC-800 are the active sites. PNC-800 catalyzes the decomposition of hydrogen peroxide to generate hydroxyl radical (HȮ), which oxidizes furfural to furfural radical, and the furfural radical is subsequently converted to 5-hydroxy-furan-2(5H)-one (HFONE). The conversion of furfural to maleic acid via the formation of HFONE is the main reaction pathway. In addition, the hierarchical porous structure with a high specific surface area facilitates the interaction of reactant with the active sites. PNC-800 has been shown an excellent catalytic activity for the production of maleic acid from furfural. For the oxidation of 1000 mM furfural using 50 mg PNC-800 at 80 °C within 9 h, the conversion of furfural is 100 % with a maleic acid yield 67.5 %.

One-Step Synthesis of Nitrogen-Doped Porous Carbon Derived from Biomass for Lithium-Ion Battery

Bamboo shoot is renewable biomass rich in carbon and nitrogen. To take advantage of its sources of carbon and nitrogen, hierarchical porous nitrogen-doped carbon materials derived from bamboo shoot were acquired via a one-step method in this study. The obtained carbons were characterized by using XRD, Raman, N2 sorption, SEM, TEM, XPS, etc. The carbon calcinated at 700 °C with KHCO3 treatment (BSC) displays a large surface area (1475.5 m2 g−1) and typically porous structure from micro- to macropores, a self-nitrogen content, and many defects, which could offer transport channels and active sites for lithium ions while used as carbon anode. Based on the above features and the synergistic effects among them, BSC exhibits the typical electrochemical performance of a carbon-based anode material, with a specific capacity as high as 611.3 mA h g−1 (a Coulombic efficiency of 98.7%) after 100 cycles at a current density of 0.1 A g−1. Meanwhile, it also has a good rate performance and excellent cycling properties (436.1 mA h g−1 after 300 cycles at 0.1 A g−1) compared with NBSC (carbon directly carbonized at 700 °C). Thus, it is promising for further improvements made to porous carbon derived from biomass and used as anode in the application of energy storage, and could be a guideline for the preparation of high-value-added carbon materials derived from biomass.

High Rate Performance Supercapacitors Based on N, O Co-Doped Hierarchical Porous Carbon Foams Synthesized via Chemical Blowing and Dual Templates.

N, O Co-Doped porous carbon materials are promising electrode materials for supercapacitors. However, it is still a challenge to prepare high capacitance performance N, O Co-Doped porous carbon materials with balanced pore structure. In this work, a simple chemical blowing method was developed to produce hierarchal porous carbon materials with Zn(NO3)2·6H2O and Fe(NO3)3·9H2O as the foaming agents and precursors of dual templates. Soybean protein isolate served as a self-doping carbon source. The amount of Fe(NO3)3·9H2O influenced the microstructure, element content and capacitance performance of the obtained porous carbon materials. The optimized sample CZnFe-5 with the addition of 5% Fe(NO3)3·9H2O displayed the best capacitance performance. The specific capacitance reached 271 F g-1 at 0.2 A g-1 and retained 133 F g-1 at 100 A g-1. The CZnFe-5//CZnFe-5 symmetric supercapacitors delivered a maximum energy density of 16.83 Wh kg-1 and good stability with capacitance retention of 86.33% after 40,000 cycles tests at 50 A g-1. The symmetric supercapacitors exhibited potential applications in lighting LED bulbs with a voltage of 3 V. This work provides a new strategy for the synthesis of hierarchical porous carbon materials for supercapacitors from low-cost biomass products.

Tailoring hierarchically porous structure of biomass-derived carbon for high-performance supercapacitors

Biowaste-derived hierarchical porous carbon materials and understanding their structure-property relationship have a significant impact on the development of low-cost and high-performance supercapacitors. Herein, we report the effective one-step construction of large specific surface area and hierarchical porous carbon materials (CPC) using waste corncobs as raw material and investigated the relationship between intrinsic pore characteristics and specific capacitance. The textural properties such as surface area and pore characteristics, are controlled by modulating the various activating agent, carbonization temperature and time. The as-prepared porous carbon material (particularly CPC-3) at activation temperature of 700 °C obtained via potassium permanganate modulation with optimal specific surface area and volume of pores 1612.86 m2 g−1 and 2.25 cm3 g−1, which exhibited the ultra-high capacitance of 691.05 F g−1 at a current density of 0.5 A g−1 with good rate capability. In addition, the electrode exhibits excellent capacitance retention of 109.7 % over 10000 charge-discharge cycles at a current density of 10 A g−1. Furthermore, the assembled symmetric supercapacitor using CPC-3 and PVA-KOH gel electrolyte delivered a high energy/power density of 16.47 Wh kg−1/15360 W kg−1, respectively. The as-prepared quasi-solid-state device also shows superior applicability and outstanding cycling stability over a wide temperature range of −25 to +60 °C. This work provides a fundamental understanding of the structure-property relationship of the biomass-derived hierarchical porous carbon and allows for the development of supercapacitors in harsh temperature conditions.

Size-matched hierarchical porous carbon materials anchoring single-atom Fe-N4 sites for PMS activation: An in-depth study of key active species and catalytic mechanisms

Single-atom catalysts are considered to be one of the most promising catalysts for AOPs. However, how to design and synthesize cost-effective and highly loaded single-atom catalysts is the bottleneck limiting its development and application. In this study, we report a highly loaded single-atom iron catalyst (Fe-SAC-BC) using waste biomass as a carbon carrier to anchor Fe-N4 sites. The catalyst showed excellent catalytic performance and stability in wastewater treatment. Unlike conventional radical oxidation, the non-radical degradation process of Fe-N4 as the active site and high-valent iron-oxygen intermediates as the key active species identified by burst and probe experiments. DFT calculations and molecular dynamics simulations were applied to the catalytic mechanism of Fe-SAC-BC, in which Fe (III)-N4 is the most likely active site and Fe (IV)-OH is the most dominant active species. This study provides new strategies and understanding for the design of novel single-atom catalysts and the mechanistic probing of the non-radical pathways of AOPs.

Heteroatom-doped layered hierarchical porous carbon electrodes with high mass loadings for high-performance supercapacitors

Electrodes with high mass loadings are the impetus for improving the energy density of supercapacitors. However, such electrodes have poor charge and ion kinetics in most cases, and rationally designing them which have high electron and ion transport rates is a major challenge. In this work, a new heteroatom-doped hierarchical porous carbon material, called LPC-2, was developed with longan shell and KOH as its precursor and an activator, respectively, through heteroatom self-doping and architecture design integration, in which heteroatoms of nitrogen, oxygen and sulfur were found. Its frequency response was excellent at a scan rate up to 5 and 0.3 V s−1 when the mass loading was set to be 1.0 and 12 mg cm−2, respectively. At a high mass loading of 12 mg cm−2, LPC-2 had gravimetric and areal specific capacitances of 171 F g−1 and 2052 mF cm−2, respectively. The assembled LPC-2//LPC-2 symmetric supercapacitor can complete charge and discharge in 0.4 s, showing a high energy density of 10.8 Wh kg−1 at a high power density of 97.4 kW kg−1 in 6 M KOH. In addition, 99.5 % of the original capacitance was retained after 20,000 cycles at 10 A g−1, which embodies the application value of biomass-derived carbon in supercapacitors.

Porous Carbon for CO2 Capture Technology: Unveiling Fundamentals and Innovations

Porous carbon is an emerging material for the capture of CO2 from point sources of emissions due to its high structural, mechanical, and chemical stability, along with reusability advantages. Currently, research efforts are mainly focused on high- or medium-pressure adsorption, rather than low-pressure or DAC (direct air capture) conditions. Highly porous and functionalized carbon, containing heteroatoms (N, O, etc.), is synthesized using different activation synthesis routes, such as hard template, soft template, and chemical activation, to achieve high CO2 capture efficiency at various temperatures and pressure ranges. Fundamental pore formation mechanisms with different activation routes have been evaluated and explored. Higher porosity alone can be ineffective without the presence of proper saturated diffusion pathways for CO2 transfer. Therefore, it is imperative to emphasize more rational multi-hierarchical macro-/meso-/micro-/super-/ultra-pore design strategies to achieve a higher utilization efficiency of these pores. Moreover, the present research primarily focuses on powder-based hierarchical porous carbon materials, which may reduce the efficiency of the capture performance when shaping the powder into pellets or fixed-bed shapes for applications considered. Therefore, it is imperative to develop a synthesis strategy for pelletized porous carbon and to explore its mechanistic synthesis route and potential for CO2 capture.

Hierarchically Porous Carbon Nanosheets from One-Step Carbonization of Zinc Gluconate for High-Performance Supercapacitors.

Supercapacitors, with high energy density, rapid charge-discharge capabilities, and long cycling ability, have gained favor among many researchers. However, the universality of high-performance carbon-based electrodes is often constrained by their complex fabrication methods. In this study, the common industrial materials, zinc gluconate and ammonium chloride, are uniformly mixed and subjected to a one-step carbonization strategy to prepare three-dimensional hierarchical porous carbon materials with high specific surface area and suitable nitrogen doping. The results show that a specific capacitance of 221 F g-1 is achieved at a current density of 1 A g-1. The assembled symmetrical supercapacitor achieves a high energy density of 17 Wh kg-1, and after 50,000 cycles at a current density of 50 A g-1, it retains 82% of its initial capacitance. Moreover, the operating voltage window of the symmetrical device can be easily expanded to 2.5 V when using Et4NBF4 as the electrolyte, resulting in a maximum energy density of up to 153 Wh kg-1, and retaining 85.03% of the initial specific capacitance after 10,000 cycles. This method, using common industrial materials as raw materials, provides ideas for the simple preparation of high-performance carbon materials and also provides a promising method for the large-scale production of highly porous carbons.

Optimizing pre-carbonization temperature of sesame residue for hierarchical porous carbon materials in high-performance supercapacitor applications

In this paper, the sesame residue, a common biomass waste, was used as a precursor to synthesize N,O co-doped porous carbon materials via a simple pre-carbonization and KNO3 activation two-step strategy. The apparent morphology and supercapacitor performance of the obtained materials can be regulated by changing the pre-carbonization temperature (0 °C, 300 °C and 600 °C). The consequences demonstrate that a large number of C−C and C−O bonds in sesame residue undergo cleavage and form abundant pore structure at the pre-carbonization temperature of 300 °C. After KNO3 activation, the material has a moderate specific surface area (1073.4 m2 g−1) and affluent heteroatom content (N: 7.52 at%, O: 17.65 at%). As a result, the SS-300 electrode displays exceptional capacitive performance (specific capacitance up to 312.7 F g−1 at 0.5 A g−1) and outstanding cyclic stability (capacitance retention reaching 98.3% at 10 A g−1 after 8000 charge–discharge cycles). Moreover, the symmetric supercapacitor assembled by SS-300 exhibits high energy densities in both 6 M KOH (4.58 Wh kg−1) and 1 M Na2SO4 (15.60 Wh kg−1), highlighting the potential of this material for energy storage applications.

Application of pitch-based multi cavity carbon microsheets in capacitive deionization removal of NO3–

Capacities deionization (CDI) denitrification technology has attracted considerable attention, and electrode materials with nitrate adsorption properties have become a research hotspot. In this study, a multi cavity carbon microsheets (MCCM-5) was prepared using a hard template method and low-cost nitrated pitch as a carbon source. The results of the electrosorption experiments showed that the material had an excellent capacity of NaNO3 (45 mg g−1). Furthermore, although the actual specific surface area and specific capacitance of MCCM-5 are lower than those of hierarchical porous carbon materials (HPCM-1), MCCM-5 exhibit lower diffusion and charge-transfer resistances, resulting in a better denitrification performance. The adsorption capacity of MCCM-5 for NaNO3 was twice that HPCM-1 and 11.8 times that of commercial activated carbon, which is superior to the material properties reported thus far. Our analysis indicated that the material combined the advantages of both a layered structure and hierarchical pores. First, the uniformly distributed hierarchical pores in the layered structure enhanced the ion concentration potential. Second, the layered structure provided good ion diffusion channels, thereby increasing the effective adsorption area of the material. DFT calculation shows that the carbon cavity structure enriched in the material shows a stronger adsorption capacity for NO3–, which can promote the electron transfer process during NO3– adsorption. This study shows that a precise regulation of the carbon material structure can be achieved by adjusting the size of the template material and carbonization conditions to obtain a higher adsorption capacity and provides a new idea for the structural optimization of electrode materials.

An unconventional direct path for the chemoselective hydrogenation of nitroarenes over a metal-free catalyst

In recent years, significant efforts have been devoted to the fabrication of heteroatom-doped carbon materials as ecofriendly catalysts to replace metal-based catalysts employed in the hydrogenation of nitroarenes. However, the reaction pathway of metal-free catalysts has not been thoroughly studied. In this study, nitrogen-doped hollow hierarchical porous carbon materials have been successfully prepared. The porous nitrogen-doped carbon was prepared by carbonizing at 900°C (PNC-900) and exhibited an exceptional catalytic performance in the chemoselective hydrogenation of nitroarenes with high tolerance to various substrates under mild reaction conditions. The analysis of the experimental results and characterizations, revealed that graphitic N species were the primary catalytic active sites and played a crucial role in efficient hydrogenation. The reaction followed a special direct path in the hydrogenation of nitrobenzene (NB) owing to the absence of nitrosobenzene (NSB) as an intermediate, which was markedly different from the other metal-free catalysts. Moreover, the PNC-900 catalyst exhibited excellent reactivity and selectivity even after six cycling tests, thus demonstrating unconventional high performance in terms of both recyclability and stability.

Hierarchical magnetic nitrogen-doped porous carbon derived from a covalent organic framework (COF) for the highly efficient removal of sulfamerazine

The occurrence of sulfonamides in the water environment has garnered significant attention due to their potential adverse effects on ecosystems and human health. Despite this significance, effectively removing sulfonamides from polluted water sources remains a challenging task. In this study, a series of hierarchical magnetic porous carbon materials (M-NPC) doped with iron and nitrogen are prepared using a direct carbonization method, employing a covalent organic framework (COF) as a precursor. The resulting M-NPC exhibits a hierarchical structure, high porosity, and abundant N-containing binding sites, enabling efficient removal of sulfamerazine (SMR) within 2 min. Mechanism studies reveal that the adsorption of SMR by M-NPC followed the pseudo-second-order kinetic model (R2 = 0.999) and the Freundlich model. Furthermore, electrostatic interactions, π-π stacking, and hydrogen bond interactions are identified as the dominant mechanisms contributing to excellent adsorption performance. Additionally, the M-NPC demonstrates easy operation and good regeneration ability, making it highly promising for the efficient removal of sulfonamides from wastewater. This development marks a significant advancement in addressing the challenge of removing sulfonamides from polluted water sources.