Porous Graphitic Carbon Materials Research Articles

Cobalt-molybdenum bimetallic catalyst effect on biomass-derived graphitic carbon

The development of highly graphitized and porous carbon materials is important for the evaluation of wastes and their use in energy applications. In this study, we focused on the production of simple, safe, and sustainable porous graphitic carbon (GC) materials using an important waste source in the Black Sea region. Catalytic graphitization method was used for the conversion of hazelnut shell powder with low ash (0.11 %) and high carbon (50.85 %) content to GC. The effects of metallic Co and bimetallic Co-Mo catalysts at different ratios on the graphitization mechanism as well as the chemical, structural and surface properties of the produced GCs were investigated. It was determined that Co:Mo= 1:4 is the most suitable ratio due to the emergent synergistic effect. In the HS-Co-Mo-1-4, the ID/IG ratio was found to be 0.876, while the Braun-Emmet-Teller surface area (SBET) was measured as 266.5 m2/g.

Fabrication of dual heteroatom-doped graphitic carbon from waste sponge with “killing two birds with one stone” strategy for advanced aqueous zinc–ion hybrid capacitors

Emerging aqueous zinc–ion hybrid capacitors (AZICs) are considered a promising energy storage because of their superior electrochemical performance. The pore structure, suitable heteroatom content, and graphitization degree (GD) of carbon-based cathodes significantly influence the electrochemical performance of AZICs. The N, S dual-doped porous graphitic carbon materials (LC-750) with the combined characteristics of high GD (1.11) and large specific surface area (1678.38 m2 g−1) are successfully developed by a facile “killing two birds with one stone” strategy using K3Fe(C2O4)3·3H2O as the activating and graphitizing agent, and waste sponge (WS) and coal tar pitch (CTP) as the heteroatom and carbon resource, respectively. Results show that the LC-750 cathode displays high capacities of 185.3 and 95.2 mAh g−1 at 0.2 and 10 A g−1. Specifically, the assembled LC-750//Zn capacitor can offer a maximal energy density of 119.5 Wh kg−1, a power density of 20.3 kW kg−1, and a capacity retention of 87.8% after 15,000 cycles at 10 A g−1. Density functional theory simulations demonstrate that N and S dual-doping can promote the adsorption kinetics of Zn ions. This design strategy is a feasible and cost-effective method for the preparation of dual heteroatom-doped graphitic carbon electrodes, which enables recycling of WS and CTP into high-valued products.

Metal-organic framework derived inverse opal type 3D graphitic carbon for highly stable lithium-ion batteries.

Graphitic carbon-based anodes for lithium-ion batteries have seen remarkable development and commercial acceptance during the past three decades. Still, the performance of these materials is limited due to the low surface area, stacking of layers, poor porosity, and meager conductivity. To overcome these limitations, we propose using polystyrene as a core and small-sized zeolitic imidazolate framework-67 (ZIF-67) particles as decorators to develop a highly porous three-dimensional graphitic carbon material. The developed material is optimized with the carbonization temperature for the best anodic performance of LIBs. The pyridinic nitrogen content in the material carbonized at 700 °C makes it high performing and more stable than the samples treated at 600, 800, and 900 °C. The packed coin cell exhibited an initial discharge capacity of 775 mA h g-1 at a current density of 50 mA g-1, which increases to 806 mA h g-1 after testing the material at different current densities for 55 cycles. The packed half-cell exhibited a highly stable performance of about 96% even after testing for 2000 cycles at 1 A g-1.

Porous Graphitic Carbon-Based Imprint Mass Spectrometry Imaging with an Ambient Liquid Extraction Technique for Enhancing Coverage of Glycerolipids and Sphingolipids in Brain Tissue.

Localization of lipidomes and tracking their spatial changes by mass spectrometry imaging (MSI) is critical for the mechanism studies on living process, disease, and therapeutic treatment. However, due to the strong ion suppression in complex biotissue, the imaging coverage for lipids with low polarity or low abundances, such as glycerolipids and sphingolipids, is usually limited. To address this issue, we utilized a porous graphitic carbon (PGC) material to imprint brain tissue sections for selective enrichment of neutral lipids with polar phospholipids removed. Then, the tissue imprint was scanned for desorption by the ambient liquid extraction MSI system. It was found that on the PGC surface, hydrophobic interaction dominates in protic solvents, and polar interaction dominates in aprotic solvents. Accordingly, methanol was selected as the spray solvent for tissue imprinting, and 75% acetonitrile-methanol was selected as the desorption solvent for the ambient liquid extraction MSI system. The results showed that glycerides had high recoveries after the imprinting-desorption process (recovery ∼ 70%) with phospholipids eliminated (recovery < 7%). To increase the transferring efficiencies of lipids from tissue onto PGC, electrospray was used for solvent application during imprinting, and the signals of diglycerides (DGs) in the imprint MSI of brain tissue increased by 2-3 times as compared to those via air spray. Finally, the new imprint MSI approach was applied to the imaging of the rat cerebellum and was compared with direct tissue MSI. The results showed that with imprint MSI, the coverage of DGs, sphingomyelins (SMs), and ceramides was enhanced by 4-5-fold (32 vs 6, 4 vs 1, and 5 vs 0). The ion images showed that with imprint MSI, higher signal intensities and clearer spatial distribution of DGs and SMs were obtained without interference from phosphatidylcholine signals compared with tissue MSI. This new method provides a complementary approach for traditional MSI to address the issues in imaging poorly ionizable or low-abundance lipids.

Hierarchically Porous Carbon Derived from a Mn2+ Complex: A Highly Graphitized Structure for Supercapacitor Applications

AbstractPorous graphitic carbon materials have been regarded as promising candidates as the electrode for supercapacitors. However, the high porosity and electrical conductivity usually have a competitive relationship in a carbon material. Therefore, constructing the hierarchically porous graphitic carbon materials poses a challenge. We report a simple one‐pot synthesis strategy using a Mn complex both as the hard template and the graphitization catalyst. The pore size distribution of porous carbon can be adjusted, and MnCx can be produced by the combination of MnO with amorphous carbon atoms. The as‐prepared carbon materials show a high graphitization degree and surface area of 1545 m2 g−1 with micro‐/mesopores, which boosts the rate performance with capacitance retention up to 90 % at 50 A g−1 and gives super cycle performance with 100 % capacitance retention after 10 000 cycles for the electrode of symmetric supercapacitor. This work reveals a novel strategy to construct porous graphitic carbon materials for supercapacitors applications.

N/O/P co-doped hierarchical porous graphitic carbon materials for high-rate supercapacitors

Heteroatoms-doped hierarchical porous carbons have attracted considerable interest owing to their efficient utility in supercapacitors. However, the increase of defects tends to sacrifice the electrical conductivity of carbon materials. Therefore, it is of great significance to build a good conductive network by increasing the graphitization degree of porous carbons. Here, this study reports the use of serine phosphate protic salt ([Seri][H2PO4]), Pluronic F127 and cobalt nitrate to engineer the N/O/P co-doped hierarchical porous graphitic carbon materials. The Co2+ catalyzes the graphitization of porous carbons under high temperature. A large number of mesopores, highly doped heteroatoms (O: 4.2 wt%, N: 4.07 wt%, P: 0.81 wt%) and conductive carbon skeleton boost the ultrafast transport of electrons and ions, resulting in high specific capacitance, wide operating voltage and outstanding rate performance. The symmetric supercapacitor assembled in KOH electrolyte shows good frequency response with the scan rate up to 1.5 V s−1 on the working voltage of 0–1.3 V. At the same time, when the power density reaches up to 21.3 kW kg−1, its energy density remains 8.74 W h kg−1. Furthermore, the symmetric supercapacitor delivers a high energy density of 81.42 W h kg−1 at the power density of 875 W kg−1 with an ultrahigh working voltage of 3.5 V in 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF4) electrolyte. More promisingly, all-solid device based on the optimized sample exhibits outstanding flexibility, which greatly broadens its practicability. This work marks the importance of the balance between porous structure, heteroatom doping and high conductivity for advanced supercapacitors.

Design and structure optimization of 3D porous graphitic carbon nanosheets for high-performance supercapacitor

Abstract The restacking and less pore structure of carbon nanosheets severely prolong ion transport pathways when ions diffuse in vertical direction. Here, we design and fabricate 3D porous graphitic carbon material with synergetic features combining porous nanosheets and fiber network. With the assistant of activation–graphitization effect of bifunctional catalyst K3[Fe(C2O4)3] and fiber framework of melamine foam, glucose-derived ultrathin carbon nanosheets with porous and graphitic structure are supported by fiber skeleton after one-step carbonization. Sufficient ion-accessible micropores, partially graphitic carbon nanosheets and interconnected fiber skeleton can intrinsically optimize ion/electron transport and ensure high level exposure of active surface area for charge accumulation. Therefore, the obtained material possesses high specific capacitance of 354.7 F g−1 at 0.5 A g−1, excellent rate capability of 253.3 F g−1 at 30 A g−1, and outstanding cycling stability of 96.8% retention after 10000 cycles. A high energy density of 24.5 W h kg−1 (at 456.7 W kg−1) is achieved in 1 M Na2SO4. This study not only provides a promising approach for constructing porous graphitic carbon nanosheets, but also opens a new direction to optimize ion/electron transport for high-performance of energy storage.

A new strategy to immobilize molecular Fe sites into a cationic polymer to fabricate an oxygen reduction catalyst

We report a new method of generating catalytic active sites for the oxygen reduction reaction (ORR) through the immobilization of molecular Fe sites in a cationic polymer (CXL-HCP-Fe) via counterion exchange combined with pyrolysis. Pyrolysis at different temperatures leads to the formation of novel non-precious metal catalysts consisting of Fe3C nanoparticles encapsulated in porous graphitic carbon materials (CXL-HCP-Fe-t). Electrochemical characterization shows that the CXL-HCP-Fe-900 obtained at a pyrolysis temperature of 900 °C has excellent ORR electrocatalytic activity that is comparable to the commercial Pt/C catalyst, and even better catalytic durability. In addition, 57Fe Mössbauer spectroscopy, inductively coupled plasma spectrometry and X-ray diffraction measurements show that Fe3C-based active sites with relatively high crystallinity species and content contribute to the high ORR catalytic activity of CXL-HCP-Fe-900.

Biomass-derived porous graphitic carbon materials for energy and environmental applications

This review presents the applications of biomass-derived porous graphitic carbon materials and their synthetic methods.

Highly graphitized and N, O co-doped porous carbon derived from leaves of viburnum sargenti with outstanding electrochemical performance for effective supercapacitors

Constructing the porous graphitic carbon materials based on the renewable biomass-derived raw materials has raised widely attention in recent years. Herein, this work proposes a cost-effective and eco-friendly approach for fabricating the highly graphitic porous carbon (HGPC) materials using leaves of viburnum sargenti for the first time. The as-prepared carbon sample exhibits a moderate specific surface area of 762.3 m2/g, a high oxygen content of 16.75 at.%, which could contribute additional pseudocapacitance during electrochemical reaction process. And the doping of nitrogen atom (0.53 at.%) could availably improve the conductivity. Consequently, the HGPC electrode delivers an excellent specific capacitance of 612.8 F/g at 0.5 A/g and a remarkable cycling stability with 96.02% capacitance retention over 10,000 cycles. Additionally, the assembled HGPC//HGPC symmetric supercapacitor presents an ultrahigh energy density of 25.6 Wh/kg at the power density of 450 W/kg. This facile technique holds great promise to offer an effective and universal methodology for fabricating renewable biomass-derived carbon materials for high-performance supercapacitors.

One-step synthesis of N, S-codoped porous graphitic carbon derived from lotus leaves for high-performance supercapacitors

The development of high-performance biomass-derived porous graphitic carbon materials is in high demand for applications in supercapacitors. Herein, a novel N, S self-codoped porous graphitic carbon is synthesized by one-step carbonization of lotus leaves together with urea and ferric chloride. Due to the combination of urea as a nitrogen doping agent and ferric chloride as both activating agent and graphitization catalyst, the obtained lotus leaf–derived porous graphitic carbon material possesses a high specific surface area of 975.7 m2 g−1, appropriate pore structure with interconnected macropores, suitable graphitization level, and high N, S contents. The resultant porous graphitic carbon electrode shows a high specific capacitance of 385.0 F g−1 at 0.5 A g−1 (based on a three-electrode system in 6 M KOH electrolyte), and good rate capability (140.0 F g−1 at 100 A g−1). Furthermore, the assembled carbon-based symmetric supercapacitor delivers a high energy density of 29.5 Wh kg−1 at a power density of 545.6 W kg−1 and excellent long-term cycling stability (95.3% of the initial capacitance after 20,000 cycles at 5 A g−1). This work provides a general method to synthesize porous graphitic carbon from biomass for electrochemical energy storage and conversion.

Vapor-assisted synthesis of hierarchical porous graphitic carbon materials towards energy storage devices

Hierarchical porous graphitic carbon material is obtained by one-step vapor-assisted catalytic graphitization accompanied with chemical activation of phenolic resin. Water vapor is used to enhance the catalytic graphitization process by etching carbon layers coated on metal nanocatalysts to maintain their high catalytic activity, and the resultant hydrogen and carbon monoxide as strong reduction gases arising from water-gas shift reaction can promote the transformation of metal ions to metal catalysts. Thus, the resultant graphitic carbon exhibits hierarchical pore structure, large surface area and high graphitic degree, which is advantageous over conventional activated carbon materials in electrochemical energy storage. The applications of hierarchical porous graphitic carbon as electrode materials for supercapacitors, and host for sulfur in lithium-sulfur cells is demonstrated, which shows remarkably enhanced electrochemical performance due to the unique structure.

Nano LC-MS using capillary columns enables accurate quantification of modified ribonucleosides at low femtomol levels.

Post-transcriptional chemical modifications of (t)RNA molecules are crucial in fundamental biological processes, such as translation. Despite their biological importance and accumulating evidence linking them to various human diseases, technical challenges have limited their detection and accurate quantification. Here, we present a sensitive capillary nanoflow liquid chromatography mass spectrometry (nLC-MS) pipeline for quantitative high-resolution analysis of ribonucleoside modifications from complex biological samples. We evaluated two porous graphitic carbon (PGC) materials and one end-capped C18 reference material as stationary phases for reversed-phase separation. We found that these matrices have complementing retention and separation characteristics, including the capability to separate structural isomers. PGC and C18 matrices yielded excellent signal-to-noise ratios in nLC-MS while differing in the separation capability and sensitivity for various nucleosides. This emphasizes the need for tailored LC-MS setups for optimally detecting as many nucleoside modifications as possible. Detection ranges spanning up to six orders of magnitude enable the analysis of individual ribonucleosides down to femtomol concentrations. Furthermore, normalizing the obtained signal intensities to a stable isotope labeled spike-in enabled direct comparison of ribonucleoside levels between different samples. In conclusion, capillary columns coupled to nLC-MS constitute a powerful and sensitive tool for quantitative analysis of modified ribonucleosides in complex biological samples. This setup will be invaluable for further unraveling the intriguing and multifaceted biological roles of RNA modifications.

Three-dimensional interconnected porous graphitic carbon derived from rice straw for high performance supercapacitors

Three-dimensional interconnected porous graphitic carbon materials are synthesized via a combination of graphitization and activation process with rice straw as the carbon source. The physicochemical properties of the three-dimensional interconnected porous graphitic carbon materials are characterized by Nitrogen adsorption/desorption, Fourier-transform infrared spectroscopy, X-ray diffraction, Raman spectroscopy, Scanning electron microscopy and Transmission electron microscopy. The results demonstrate that the as-prepared carbon is a high surface area carbon material (a specific surface area of 3333 m2 g−1 with abundant mesoporous and microporous structures). And it exhibits superb performance in symmetric double layer capacitors with a high specific capacitance of 400 F g−1 at a current density of 0.1 A g−1, good rate performance with 312 F g−1 under a current density of 5 A g−1 and favorable cycle stability with 6.4% loss after 10000 cycles at a current density of 5 A g−1 in the aqueous electrolyte of 6M KOH. Thus, rice straw is a promising carbon source for fabricating inexpensive, sustainable and high performance supercapacitors' electrode materials.

Synthesis of porous graphitic carbon from biomass by one-step method And its role in the electrode for supercapacitor

Porous graphitic carbon materials (PGCs) with a microtubular structure were synthesized by a simple method simultaneously completing graphitization and activation for the mixture of willow catkins, KCl, and different ferric salts. The introduction of KCl was crucial to develop a porous structure. KCl, replacing corrosive KOH or poisonous ZnCl2, greatly decreased the cost for production of PGCs. The resulting material PGCN, which was produced by willow catkins, KCl, and Fe(NO3)3, not only inherited the natural microtubular morphology of willow catkins but also possessed a high graphitization degree and abundant porosity. As such, PGCN could serve as an ideal substrate for MnO2 deposition to alleviate its accumulation and improve its conductivity. The obtained PGCN/MnO2 composite electrode significantly enhanced high specific capacitance 571.1 F g− 1 at 2 A g− 1 based on the mass of MnO2. Even at a high current density of 50 A g− 1, specific capacitance still reached 382.1 F g− 1. Furthermore, the electrode exhibited outstanding cycling stability with only 14.8% degradation after 3000 cycles. This study proposes a novel graphitization–activation way for synthesis of porous graphitic carbon by utilizing biomass waste to alleviate the dependence on non-renewable sources. Schematic diagram of porous graphitic carbon by carbonizing the mixture of willow catkins, Fe(NO3)3, and KCl. The obtained PGCN which inherited the natural microtubular morphology of willow catkins had high graphitized and porous structure.

Alginate derived porous graphitic carbon for highly efficient remediation of sulfide from wastewater

Green and bio-derived porous graphitic carbon (PGC) materials were prepared through facile and sustainable method from calcium alginate natural polymer by pyrolysis at 900°C under inert atmosphere and were used to explore the possibility for the remediation of sulfide from wastewater. The graphitic carbon were characterized by N2 adsorption-desorption isotherm, Transmission Electron Microscopy, Raman spectroscopy, Scanning Electron Microscopy, X-Ray Diffraction, Fourier Transform InfraRed spectroscopy and Elemental analysis. The existence of meso-pores in PGC formed by the destruction of ‘egg box’ model of calcium alginate leads to high meso-pore volume of 0.778cc/g, comprising 96.77% of total pore volume. In order to evaluate the effectiveness of sulfide removal using PGC, the effect of contact time, initial concentration, dosage, ionic strength and equilibrium isotherms were studied at ambient temperature. The adsorption was fast and reached equilibrium within 3h with chemisorption playing a significant role. 99.87% sulfide removal was achieved using 17.0mg of PGC from an initial sulfide concentration of 45mg/L. An increasing ionic strength (using calcium chloride) decreased the% sulfide removal, while sodium chloride hardly influenced the adsorption capacity. The kinetic studies obeyed pseudo-second-order model while Freundlich isotherm could well explain the equilibrium adsorption. The adsorption mechansims showed that–COOH groups present on PGC are responsible for the removal of sulfide from wastewater. Thus, bio-derived PGC offers promising benefits to the industry for problems associated with the treatment of hazardous sulfide waste water derived from the industrial processes along with easy access to clean water resources.

P and S dual-doped graphitic porous carbon for aerobic oxidation reactions: Enhanced catalytic activity and catalytic sites

A highly porous graphitic carbon material, dually-doped with P and S, was studied as a metal free catalyst for aerobic oxidation reactions. Catalytic mechanism studies suggest that the active centers, originated from P-and S-doping, additively/synergistically catalyze the aerobic oxidation of benzylic alcohols but with different pathways. For the first time, catalytic centers stemming from S-doping were experimentally identified to be exocyclic S species (C-S-C, sulfur out of the carbon ring), which are different from those proposed for electrochemical oxygen reduction reactions (ORR) with a 4e− pathway and oxygen evaluation reactions (OER). Notably, all the catalytic sites from both P and S doping share a similar “protruding out” pyramid structure, which is in contrast to the planar structure of the catalytic sites in N- or B-doped graphitic materials. The unique geometric structure of the catalytic sites can minimize substrate steric hindrance effects, endowing the P, S co-doped catalysts with a wide substrate scope and functional group tolerance. Furthermore, the unambiguous distinguishment of the catalytic sites from those in OER and ORR provides valuable guidance for designing and developing carbon materials with controlled active sites to satisfy different catalytic applications.

Separation of Isomers of JWH-122 on Porous Graphitic Carbon Stationary Phase with Non-Aqueous Mobile Phase Using Intelligent Software.

Cannabimimetic compounds have gained an increasing attention from the forensic community during the past few years. The present study was aimed to develop a liquid chromatographic separation method for the analysis of JWH-122 and its methyl isomers. In Hungary, JWH-122 is scheduled as a narcotic compound and its methyl isomers fall into the new psychoactive substance category, attracting significantly milder punishment than JWH-122 does. According to our best knowledge, gas chromatography or reversed phase liquid chromatography coupled with mass spectrometry could not be applied for separation and selective determination of methyl-naphthoyl indol isomers. In this study, we aimed to develop a high performance liquid chromatography method with UV and mass spectrometric detection for the separation of JWH-122 and all its possible isomers, depending on the position of methyl group on the naphthyl frame. Different reversed phase columns were used. Alkyl-modified silica with different selectivity and morphology with different mobile phase composition cannot be applied for separation of JWH-122 isomers. Porous graphitic carbon (PGC) column was used for separation of banned JWH-122 and each of its methyl isomers. In method development, a Quality by Designapproach is presented for modeling the retention of the compounds. According to our knowledge, this is the first time reporting the use of intelligent software to estimate the retention on PGC material and using non-aqueous conditions. Retention times predicted by two program packages (STATISTICA® and DryLab®) are compared. The possibilities and limitations of the software modeling in the conditions described above are also evaluated.

Simultaneous analysis of heparosan oligosaccharides by isocratic liquid chromatography with charged aerosol detection/mass spectrometry

Uncovering the biological roles of heparosan oligosaccharides requires a simple and robust method for their separation and identification. We reported on systematic investigations of the retention behaviors of synthetic heparosan oligosaccharides on porous graphitic carbon (PGC) column by HPLC with charged aerosol detection. Oligosaccharides were strongly retained by PGC material in water-acetonitrile mobile phase, and eluted by trifluoroacetic acid occurring as narrow peaks. Addition of small fraction of methanol led to better selectivity of PGC to oligosaccharides than acetonitrile modifier alone, presumably, resulting from displacement of methanol to give different chemical environment at the PGC surface. Van’t-Hoff plots demonstrated that retention behaviors highly depended on the column temperature and oligosaccharide moieties. By implementing the optimal MeOH content and temperature, a novel isocratic elution method was successfully developed for baseline resolution and identification of seven heparosan oligosaccharides using PGC-HPLC–CAD/MS. This approach allows for rapid analysis of heparosan oligosaccharides from various sources.

Porous graphitic carbon materials prepared from cornstarch with the assistance of microwave irradiation

Porous graphitic carbon materials (PGCs) have attracted great interest because of their properties shown in fields such as catalyst supports, electrochemical double layer capacitors, Li-ion batteries, etc. Biomass is a promising resource to produce PGCs, as it is cheap, eco-friendly and renewable. Using cornstarch as raw material, two PGCs (PGC-1 and PGC-2) were prepared by combining microwave-assisted catalytic graphitization and chemical activation. PGC-1 was made from new gelatinized starch and the other (PGC-2) from retrograded starch. The former was mainly composed of graphitic nanocoils. The latter, on the other hand, was more likely to be a product of activated loose packing carbonaceous sheets. Narrowly distributed hierarchical pores were observed in the PGCs. Both of the PGCs were partly graphitized and had large surface areas (353 m2/g for PGC-1 and 686 m2/g for PCG-2). Cyclic voltammetry and electrochemical impedance spectroscopy test showed that they had good capacitive property.