Obtained Carbon Materials Research Articles

Nanoporous carbon materials: modern production methods and applications

The review presents data on the nomenclature and production methods of the most intensively investigated classes of nanoporous carbon materials, which are increasingly used in science, medicine, and various fields of economy. The traditional activated carbons, which are produced by conventional biomass and fossil hydrocarbon processing methods, are compared with nanoporous carbon materials obtained using modern synthetic methods. Recommendations are given on the use of template synthesis to obtain carbon materials with a controlled nanoporosity. Self-template synthesis, in which environmentally benign and readily available organic salts can be used as precursors, is considered as a promising avenue of research. This approach markedly reduces the cost of template synthesis of nanoporous carbons and allows for the preparation of carbon materials with specific particle morphology from organometallic precursors. Methods for the preparation of functional materials with ordered architectures of micro- and mesopores are considered, including modern functionalization and doping approaches. A part of the review is devoted to advanced applications of nanoporous carbon materials such as water treatment, energy and hydrogen storage, separation of gas mixtures, development of catalysts and sensors, and solution of other significant problems. The conclusion summarizes the experience of application of various methods for the preparation of nanoporous carbon materials, identifies the most problematic issues of the development and practical use of these materials, and presents the authors' view on further development of this area of materials science.<br> The bliography includes 353 references.

High speed enrichment of benzoylurea insecticides by hierarchical pore nitrogen doped carbon materials induced with hydrogen-bonded organic frameworks

The high speed enrichment of benzoylurea insecticides (BUs) in complex matrices is an essential and challenging step. The present study focuses on the synthesis of a hierarchical pore nitrogen-doped carbon material for magnetic solid phase extraction (MSPE) of BUs. This material was prepared through the carbonization of a composite material ZIF-67@MCA which assembly with hydrogen-bonded organic frameworks (melamine-cyanurate, MCA) and zeolitic imidazolate framework (ZIF-67) at room temperature. The optimal adsorption effect is achieved when the mass ratio of ZIF-67 to MCA is 1/3, and the carbonization was performed at 600 °C, the such obtained carbon material was denoted as 1/3ZIF-67@MCA-DCs-600. The material was characterized with various physical methods including X-ray diffractometry (XRD), Fourier transform infrared spectrometry (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), Brunauer–Emmett–Teller (BET), vibrating sample magnetometer (VSM), water contact angle measurement, Raman spectrometry. 1/3ZIF-67@MCA-DCs-600 exhibits a macro-mesoporous 3D structure with a high degree of nitrogen doping and relatively large specific surface area, making it suitable for magnetic solid phase extraction (MSPE). The adsorption of BUs with concentration of 100 ng mL-1 can reach equilibrium within 5 s. The interaction between BUs and the adsorbent, facilitated by π-π stacking, hydrophobic interactions, hydrogen bonding forces, as well as the material's porosity, enables efficient extraction recoveries ranging from 45 % to 92 %. The enrichment of BUs was achieved through the establishment of an MSPE method under optimized conditions, which was further coupled with high performance liquid chromatography (HPLC) for the determination of the four BUs. The linear range spans from 5 ng ml-1 to 1000 ng ml-1 with the correlation coefficient (R2) of ≥ 0.99, Meanwhile, the detection limit for these four BUs falls within the range of 0.01 to 0.10 ng ml-1. The material exhibits good reusability and can be reused for at least 5 cycles. Inter day and intra-day precision ranges from 2.1-7.9 % and 1.0-5.4 %, respectively. The method demonstrates a high level of reliability in practical applications for the determination of BUs.

Copper-supported MOF-derived carbon materials for highly efficient antibiotics removal

Facing the escalating issue of antibiotic pollution and the emergence of bacterial resistance in water ecosystems, photocatalytic technology has been widely studied as one of the efficient methods to remove antibiotics in aquatic ecosystem. Herein, the bimetallic organic framework materials Cu/Zn-BTC were synthesized with varying proportions of copper and zinc as metal joints and 1,3,5-phthalic acid as organic ligands. Subsequently, the zinc elements within the MOF were eliminated through high pyrolysis to obtain carbon materials derived from Cu/Zn-BTC (referred to as 1.3CZC, 1.4CZC, and 1.5CZC based on the copper-to-zinc ratio). Notably, the presence of different valence copper species facilitated to form type II heterojunction within MOF-derived carbon materials, where internal Cu0/Cu+ species combined with oxygen vacancies to create localized bands that prolonged the lifetime of photogenerated carriers and enhanced photocatalytic activity. X-ray photoelectron spectroscopy, Brunauer-Emmett-Taylor and other characterization methods were used to analyze the difference in structure and performance of different catalysts. 1.4CZC showed excellent performance, upon exposure to visible light for 30 min, the removal rate of tetracycline significantly increased to an impressive 92.4 %, while extending the exposure time to 60 min further improved the removal rate of ciprofloxacin to approximately 82.6 %. It provides a highly efficient antibiotics removal pathway by MOF-derived carbon materials.

Direct pyrolysis fabrication of N/O/S self-doping hierarchical porous carbon from Platycladus Orientali leaves for supercapacitor

To meet the growing market requirement for low-cost supercapacitor electrode materials, N/O/S self-doping hierarchical porous carbon is successfully fabricated by direct pyrolysis of platycladus orientalLeaves (POL). The obtained carbon material exhibits wide application prospects, because of simple and green-environmental technology, low-cost and satisfactory electrochemical properties, which avoided complex preparation routes and consumption of expensive chemical reagents in the traditional activation process. Under the optimum pyrolysis temperature (850 °C), the obtained POL-derived carbon (POL-850) possesses a high specific surface area (1140.2 m2g−1), sheet-like hierarchical porous microstructure, and uniform ternary heteroatoms co-doping (O: 6.79 at.%; N: 3.45 at.% and S: 2.20 at.%). As an electrode material for supercapacitor, the specific capacitance of the POL-850 reaches 224.4 Fg−1 of 0.5 Ag−1and 156.0 Fg−1 at 30 Ag−1, revealing excellent rate performance. The capacitance retention maintains 96.3 % after 10,000 consecutive charge-discharge cycles at 20 Ag−1, demonstrating superior cycling stability. Additionally, the assembled carbon-based symmetric supercapacitor device delivers a satisfied energy density of 11.0 Wh kg−1 with the power density of 65 W kg−1 and ultralong cycle-lifetime with 95.65 % capacitance retention after 10,000 charge/discharge cycles, while the Coulombic efficiency is retaining up to approximately 100 %. This work provides an easy and cost-effective way to rapidly prepare N/O/S co-doping hierarchical porous carbon for supercapacitors, which is very suitable for large-scale production.

Basic magnesium carbonate template assisted co-carbonization of potassium citrate toward hierarchical porous carbon for supercapacitors

Hierarchical porous carbon (HPC) as the ideal host material for supercapacitors has received extensive attention. However, traditional methods of fabricating HPC often rely on organic macromolecules and complex procedures. Herein, a simple and straightforward approach is developed for the synthesis of HPC through basic magnesium carbonate template assisted co-carbonization of potassium citrate. Potassium citrate can be effectively embedded and encapsulated with basic magnesium carbonate due to the large bulk density difference between them. In the pyrolysis process, the carbon-containing small molecules produced by the pyrolysis of potassium citrate are deposited on the surface of MgO surface obtained from the decomposition of basic magnesium carbonate, and the etching reaction of potassium salt, CO2 and primary carbon structure occurs. The competitive rate of carbon deposition reaction and etching reaction can be easily controlled by changing the ratio of potassium citrate and basic magnesium carbonate. The obtained carbon materials show the morphology changes of nanoparticle accumulations, discontinuous carbon frames and carbon planar blocks, and the hierarchical porous structure of carbon materials can also be controlled in a wide range. HPC-2 exhibits the morphology of nanoparticle accumulation and generates abundant meso-macropores, which accelerates the rapid transport of electrolytic ions. The micropores inside the nanoparticles provide an accessible room for ionic adsorption. Benefited from this unique microstructural framework, HPC-2 shares a high capacitance of 305.5 F g−1 at 0.5 A g−1 and 173.1 F g−1 at 50 A g−1. Furthermore, the assembled symmetric supercapacitors exhibit a high energy density and power density than YP-50 F throughout the test range. The versatility of this synthetic strategy provides an insight into directional tailoring fine pore structure and micro-morphology of carbon materials based on small molecule deposition.

Effect of Thermal Activation on the Structure and Electrochemical Properties of Carbon Material Obtained from Walnut Shells.

A simple activation method has been used to obtain porous carbon material from walnut shells. The effect of the activation duration at 400 °C in an atmosphere with limited air access on the structural, morphological, and electrochemical properties of the porous carbon material obtained from walnut shells has been studied. Moreover, the structure and morphology of the original and activated carbon samples have been characterized by SAXS, low-temperature adsorption porosimetry, SEM, and Raman spectroscopy. Therefore, the results indicate that increasing the duration of activation at a constant temperature results in a reduction in the thickness values of interplanar spacing (d002) in a range of 0.38-0.36 nm and lateral dimensions of the graphite crystallite from 3.79 to 2.52 nm. It has been demonstrated that thermal activation allows for an approximate doubling of the specific SBET surface area of the original carbon material and contributes to the development of its mesoporous structure, with a relative mesopore content of approximately 75-78% and an average pore diameter of about 5 nm. The fractal dimension of the obtained carbon materials was calculated using the Frenkel-Halsey-Hill method; it shows that its values for thermally activated samples (2.52, 2.69) are significantly higher than for the original sample (2.17). Thus, the porous carbon materials obtained were used to fabricate electrodes for electrochemical capacitors. Electrochemical investigations of these cells in a 6 M KOH aqueous electrolyte were conducted by cyclic voltammetry, galvanostatic charge/discharge, and impedance spectroscopy. Consequently, it was established that the carbon material activated at 400 °C for 2 h exhibits a specific capacity of approximately 110-130 F/g at a discharge current density ranging from 4 to 100 mA/g.

Bacillus Subtilis-Derived Carbon Nanorods as Efficient ORR Electrocatalysts

Developing high-performance anion-exchange membrane fuel cells requires stable and highly active oxygen reduction (ORR) catalysts. To fabricate cheap and efficient porous carbon materials for ORR, heteroatom-doped carbon nanorods were synthesized by pyrolyzing Bacillus subtilis. The obtained carbon material maintained the uniformly distributed nanorods as original Bacillus subtilis and had inherent doped heteroatom. The obtained BS-2.0 had the highest specific surface area (209.04 m2 g−1) and the maximum ID/IG (1.0372). Its starting potential (0.93 V vs RHE) and semi-wave potential (0.81 V vs RHE) were close to 20% commercial Pt/C, and its ultimate current density was 3.98 mA cm−2@1600 rpm. Meanwhile, the stability of cycling potentiates polarization, and methanol tolerance of BS-2.0 were all greater than 20% commercial Pt/C. It was the inherent heteroatom, well-distributed nanorods, abundant pore distribution, and large surface area that contributed to its excellent electrochemical performance.

Ligin-derived graphene-like ultrathin carbon materials for ORR catalysis

Low-cost nitrogen-doped carbon materials with graphene-like structures were designed and prepared from extensive renewable biomass waste lignin. The obtained carbon materials exhibited well-designed ultrathin two-dimensional structures with high specific area and mesoporous characteristics. Benefiting from the well-designed structures with extensive catalytic active sites and efficient mass transfer and diffusion, as well as the modified electronic characteristics from nitrogen doping, the lignin-derived carbon materials exhibited pronounced ORR catalytic activity and methanol tolerance. Considering these, the lignin-derived carbon materials hold great application potentials as ORR catalysts and catalyst supports.

Optimizing capacitance performance: Solar pyrolysis of lignocellulosic biomass for homogeneous porosity in carbon production

This work compares the effect of using a solar reactor against a conventional electrical furnace to obtain carbon materials by pyrolysis of a lignocellulosic precursor. The solar reactor is directly irradiated and includes modifications to improve the control of the process and the reproducibility of solar experiments. A bagasse of agave creole was selected as the lignocellulosic precursor or biomass to obtain carbon materials at temperatures of 700 °C. Comparing carbons produced by conventional and solar pyrolysis, higher crystallinity and lower hydrophilicity are evident in the former. Moreover, conventional pyrolysis tends to promote a more homogeneous porous structure in comparison to solar pyrolysis. However, within the spectrum of solar carbons produced, the morphology of biomass plays a crucial role in influencing the chemical composition and porosity properties. Specifically, the use of fibers instead of powders to produce carbons through solar pyrolysis results in a more homogeneous porosity, attributed to an enhanced volumetric absorption of solar radiation. This modification leads to a significant improvement in capacitance, increasing from 125 F/g to 175 F/g at 5 mV/s in aqueous electrolytes. The carbons from the solar furnace are reproducible, underlying the potential of the proposed process towards a sustainable alternative. To achieve a theoretical reference, the pyrolysis process was mimic trough Reactive Molecular Dynamics calculations modeling the initial structural conditions of agave biomass with its corresponding lignocellulosic components and considering analogous thermal conditions. The resulting carbon structures at the end of the simulations showed structural properties that are consistent with those observed in the pair distribution functions obtained from XRD and the pore size distribution from physisorption analyses. This combined experimental–theoretical approach offers the potential to elucidate porous carbon structures derived from pyrolysis processes powered by solar radiation . This method can help in the design and identification of lignocellulosic structures in biomass, with the resulting carbon materials suitable for energy storage applications.

Unleashing the potential of Boratrane and Silatrane: A game-changing approach for enhanced boron- and silicon- incorporation in phenol-formaldehyde resins and their thermal stability

In this study, we present an innovative and cost-effective method for the preparation of phenolic resin (PR) containing boron and silicon (BPR and BSiPR) using boratrane and silatrane. Through a one-pot synthesis via a sol-gel process, 3BPR and 3B5SiPR are successfully synthesized, utilizing boratrane and silatrane as the sources of boron and silicon. Our results demonstrate the effective introduction of boron and silicon elements into the PR matrix through the formation of BO4 (borate) and SiO4 (silicate) structures, as evidenced by Cph-O-B and B-O-Si linkages. Notably, the utilization of boratrane in the synthesis of 3BPR leads to the formation of a uniform structure of BO4, as confirmed by 11B-NMR analysis. Furthermore, the resulting resins exhibit an improved char yield of 72 % at 900 °C. The formation of borate and silicate species effectively reduces the content of phenolic hydroxyl groups, thus contributing to a decrease in weight loss during the carbonization process. Additionally, the migration of boron and silicon into the carbon structure promotes the formation of B4C and B8C crystal structures, resulting in the carbonization of resins and the formation of a graphene-like structure, as confirmed by Raman spectroscopy, which exhibits a broad 2D-band. The obtained carbon materials possess both Lewis acid and basic sites. The presence of Lewis acid sites was characterized through pyridine-adsorbed FTIR, while the Lewis basic sites and CO2 absorption were examined via TPD-CO2 analysis. The CO2 absorption capacities of 3BPR and 3B5SiPR were found to be 0.475 and 0.518 mmol/g, respectively.

Investigation of the effect of carbonization temperature of plant biomass on the electrochemical properties of carbon material

Porous carbon materials (PСM) with different pore distributions in size and size of the specific surface area up to 250 m2/g were obtained by changing the carbonization temperature of plant biomass, namely walnut shells. The electrodes of electrochemical supercapacitors are formed based on the obtained carbon materials. The electrochemical behavior of PCM in 33% aqueous KOH solution has been studied by cyclic voltammetry and galvanostatic discharge-discharge methods and the value of their specific capacitance. The physicochemical processes occurring at the carbon electrode/electrolyte interface have been investigated by the method of impedance spectroscopy.

Changing the potassium-based activation path to prepare coal-based porous carbon with more graphitic or graphene structures for high-performance organic supercapacitors

Graphitic porous carbon is becoming an excellent platform for high-performance supercapacitors due to its unique structural characteristics, especially the combination of high specific surface area and long-range ordered sp2 carbon framework, which can synergistically improve the ion transfer/storage capability and the structural stability during long-term cycling. However, the trade-off contradiction between porosity and graphitization of carbon materials is difficult to circumvent by traditional chemical or physical activation strategies. Herein, we changed the conventional potassium-based activation pathway by introducing a pre-carbonization process, thus transforming low-rank coal precursors into graphitic porous carbon with more graphite or graphene structures. Raman mapping characterization was introduced to comprehensively reveal the distribution of crystalline carbon within the obtained carbon materials, confirming that enhancing the structural maturity of carbon-based precursors by introducing a pre-carbonization process promotes the deep and uniform development of graphitized structures during the KOH activation process. Typical reaction intermediate characterization indicates that the reason for this structural transformation is due to a change in the primary form of potassium species under the changed activation pathways, leading to a solid-liquid phase reaction environment mediated by molten K2CO3. The obtained graphitic porous carbon possesses simultaneously a hierarchically porous structure with specific surface area of 2456 m2 g−1 and well-developed graphitic carbon crystalline by which the constructed organic supercapacitor delivers excellent capacitance and rate performance, along with a high energy-power density, and a lifespan exceeding 10,000 cycles. The elucidated potassium-based activation mechanism facilitates the easy adjustment of carbon porosity and crystalline structures to meet varying requirements in different application scenarios.

Stable Supercapacitors Based on Activated Carbon Prepared from Italian Orange Juice.

The development of efficient energy storage systems is critical in the transition towards sustainable energy solutions. In this context, the present work investigates the viability of using orange juice, as a promising and sustainable precursor, for the synthesis of activated carbon electrodes for supercapacitor technologies. Through the carbonization-activation process and controlling the preparation parameters (KOH ratio and activation time), we have tailored the specific surface area (SSA) and pore size distribution (PSD) of the resulting carbon materials-crucial parameters that support supercapacitive performance. Several spectroscopic, morphological, and electrochemical techniques are used to characterize the obtained carbon materials. In particular, our optimization efforts revealed that a 5:1 KOH ratio with an activation time up to 120 min produced the highest SSA of about 2203 m2/g. Employing these optimal conditions, we fabricated symmetric coin cell supercapacitors using Na2SO4 as the electrolyte, which exhibited interesting specific capacitance (~56 F/g). Durability testing over 5000 cycles sustained the durability of the as-made activated carbon electrodes, suggesting an excellent retention of specific capacitance. This study not only advances the field of energy storage by introducing a renewable material for electrode fabrication but also contributes to the broader goal of waste reduction through the repurposing of food byproducts.

PRODUCTION OF CARBONACEOUS MATERIALS USING COAL TAR RESIN AND INVESTIGATION OF THEIR SURFACE PROPERTIES

The traditional technological process for creating highly porous materials from carbonaceous raw materials involves two stages of thermal treatment: carbonization (pyrolysis) and activation (gasification), aimed at forming a porous structure capable of adsorption. Combining both stages into a single process with chemical activation allows for efficient raw material utilization and control of the material's porous structure at different levels, providing the ability to customize its characteristics. The choice of a chemical activator depends on the type of raw material and the required characteristics of porous carbon materials. In this study, it is established that the analysis of surface properties of highly porous carbon materials synthesized from coal tar pitch, obtained by distillation of coal tar resin from JSC "Shubarkolkomir," confirms the outstanding operational characteristics of this material. The application of a combined process of carbonization and activation of coal tar pitch at an optimal temperature in an inert atmosphere leads to the formation of porous carbon materials with a high specific surface area: 561 (traditional method), 789 (chemical activation), and 881 m²/g (templating method), as well as a pore volume of 0.30; 0.40; and 0.48 cm³/g, respectively. This work not only expands the technological methods of obtaining carbon materials from coal tar resin but also underscores their potential for improving soil structure and increasing the efficiency of agricultural production.

Enhanced electrochemical performance and interdiffusion behavior of sodium ions in onion-derived freeze-dried and KOH-activated carbon for sodium-ion battery anodes

Biomass-derived carbon materials are widely regarded as promising anode materials for sodium-ion batteries (SIBs) owing to their environmental friendliness, high electronic conductivity, stability, and low cost. However, their commercial application is restricted because of their low capacities and poor cycling stabilities. Heteroatom doping and increasing the active specific surface area of carbon materials have proven to be key to solving these problems. In this study, a facile activation and annealing process combined with freeze drying and KOH treatment was used to successfully prepare nitrogen-doped onion-derived carbon materials (dried onion (DO) and freeze-dried onion (FDO)) with high specific surface areas. The obtained carbon materials exhibited excellent electrochemical performances as anodes for SIBs, delivering high discharge reversible capacities of 140.5 (DO) and 151.4 (FDO) mAh/g at a current density of 0.05 A/g after 30 cycles. The capacities reached 45 (DO) and 66 (FDO) mAh/g at 30 A/g. Specifically, FDO//Na3V2(PO4)3@C full cells achieved a reversible capacity of 43.9 mAh/g with a specific energy of 91.5 Wh kg−1 at 5 C after 1,000 cycles, indicating that it provides broad prospects for the energy storage system of SIBs.

Sulfur-Doped porous carbon Adsorbent: A promising solution for effective and selective CO2 capture

The effective and selective capture of CO2 through the rational design of microstructures and the synthesis of carbon materials with enriched surface functionality is of utmost importance in mitigating CO2 emissions. In this study, we successfully prepared a novel type of S-doped porous carbon material with a high surface area and a significant volume of micropores in a straightforward manner. This was achieved by pyrolyzing carbonized coconut shells (CS) with potassium thiosulfate K2S2O3 (PT) as an activating and sulfur supply agent. By adjusting the pyrolysis temperature within the range of 650–750 °C, we obtained carbon materials with varying surface areas (887–1924 m2/g), pore volumes (0.35–0.95 cm3 g−1), and a homogeneous distribution of sulfur content (up to 12.26 wt%) within the carbon framework. The optimal S-doped porous carbon demonstrated the adsorption capacities of 3.59 mmol g−1 at 25 °C and 5.31 mmol g−1 at 0 °C under 1 bar. Additionally, the prepared sorbent exhibited favorable CO2/N2 selectivity, high isosteric heat, and stable cycling performance. These excellent CO2 capture properties can be attributed to the materials' high microporosity and well-dispersed sulfur functionality in the carbon framework. Collectively, these findings highlight the potential of these novel carbon materials with heteroatom doping as efficient adsorbents for the selective capture of CO2, presenting a viable solution in the quest for effective CO2 mitigation.

Preparation of a High-Performance Catalyst Derived from Modified Lignin Carbon for the Hydrogen Evolution Reaction of Electrolyzed Water

Hydrogen energy is a plentiful and environmentally friendly form of secondary energy that could play a crucial role in achieving global energy sustainability. At the same time, the electrolysis of water for hydrogen production is a significant future-oriented advancement in the energy sector, whereas appropriate hydrogen evolution catalysts have always been the key to hydrogen evolution reactions. In this study, lignin was utilized as an appropriate raw material for modification in order to obtain carbon materials, which was then supported with Ru to prepare an Ru0.8@MLC catalyst. At a current density of 10 mA cm−2, the required overpotential was a mere 35.6 mV and the slope of Tafel was 31.7 mV dec−1. This study provides a feasible strategy and pathway for preparing highly efficient electrocatalysts for the hydrogen evolution reaction.

Electrochemical Performance of Nitrogen Self-Doping Carbon Materials Prepared by Pyrolysis and Activation of Defatted Microalgae.

Pyrolysis and activation processes are important pathways to utilize residues after lipid extraction from microalgae in a high-value way. The obtained microalgae-based nitrogen-doped activated carbon has excellent electrochemical performance. It has the advantage of nitrogen self-doping using high elemental nitrogen in microalgae. In this study, two kinds of microalgae, Nanochloropsis and Chlorella, were used as feedstock for lipid extraction. The microalgae residue was firstly pyrolyzed at 500 °C to obtain biochar. Then, nitrogen-doped activated carbons were synthesized at an activation temperature of 700-900 °C with different ratios of biochar and KOH (1:1, 1:2, and 1:4). The obtained carbon materials presented rich nitrogen functional groups, including quaternary-N, pyridine-N-oxide, pyrrolic-N, and pyridinic-N. The nitrogen content of microalgae-based activated carbon material was up to 2.62%. The obtained materials had a specific surface area of up to 3186 m2/g and a pore volume in the range of 0.78-1.54 cm3/g. The microporous pore sizes of these materials were distributed at around 0.4 nm. Through electrochemical testing such as cyclic voltammetry and galvanostatic charge-discharge of materials, the materials exhibited good reversibility and high charge-discharge efficiency. The sample, sourced from microalgae Chlorella residue at activation conditions of 700 °C and biochar/KOH = 1:4, exhibited excellent endurance of 94.1% over 5000 cycles at 2 A/g. Its high specific capacitance was 432 F/g at 1 A/g.

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.

Iron-loading N and S heteroatom doped porous carbon derived from chitosan and CdS-Tetrahymena thermophila for peroxymonosulfate activation

Transforming waste into resources is an important strategy to enhance the economic efficiency and reduce the waste entering the environment. In this work, iron-loading N and S co-doped porous carbon materials, as peroxymonosulfate (PMS) activator for pollutants degradation, were prepared by pyrolysis of the mixture of iron loading chitosan and CdS-Tetrahymena thermophila under N2 flow. Chitosan is mainly derived from the shell waste of shrimp and crab, and CdS-Tetrahymena thermophila is produced in the removing process of Cd2+ pollution bioremediation using Tetrahymena thermophila. The synergistic effects of iron related species and heteroatoms (S/N) co-doped porous carbon in the obtained carbon materials improved the performance for activating PMS. The prepared Fe-S-CS-1-900 exhibited high performance for the degradation of Rhodamine B (RhB) by activating PMS. Radical quenching tests and electron paramagnetic resonance measurements suggested that superoxide radical (O2−) and singlet oxygen (1O2) were the primary reactive oxygen species in RhB degradation. These results propose new insights of using biomass waste to derive Fe-loading N and S heteroatom co-doping carbon as PMS activator applied in the removal of organic pollutants.